/* ========== PAPERPOOL LISTINGS - MODERN BLACK & WHITE THEME ========== */

/* Reset & Base Styles */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', system-ui, sans-serif;
    background: #fafafa;
    color: #000;
    line-height: 1.6;
    overflow-x: hidden;
}

/* CSS Custom Properties */
:root {
    /* Colors */
    --primary-black: #000000;
    --primary-white: #ffffff;
    --gray-50: #fafafa;
    --gray-100: #f5f5f5;
    --gray-200: #e5e5e5;
    --gray-300: #d4d4d4;
    --gray-400: #a3a3a3;
    --gray-500: #737373;
    --gray-600: #525252;
    --gray-700: #404040;
    --gray-800: #262626;
    --gray-900: #171717;

    /* Accent Colors */
    --accent-blue: #3b82f6;
    --accent-green: #10b981;
    --accent-yellow: #f59e0b;
    --accent-red: #ef4444;
    --accent-purple: #8b5cf6;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Border Radius */
    --border-radius: 12px;
    --border-radius-lg: 16px;
    --border-radius-xl: 20px;

    /* Transitions */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ========== PARTICLE BACKGROUND ========== */
#particles-js {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: linear-gradient(135deg, var(--gray-50), var(--gray-100));
}

/* ========== LOADING SCREEN ========== */
.listings-loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--primary-white);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.listings-loader.hidden {
    opacity: 0;
    visibility: hidden;
}

.loader-content {
    text-align: center;
    max-width: 400px;
    padding: 2rem;
}

.loader-animation {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.search-icon {
    width: 80px;
    height: 80px;
    background: var(--primary-black);
    color: var(--primary-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    animation: searchPulse 2s ease-in-out infinite;
}

@keyframes searchPulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

.loader-text h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 0.5rem;
}

.loader-text p {
    color: var(--gray-600);
    font-size: 1rem;
}

.loader-progress {
    width: 100%;
}

.progress-bar {
    width: 100%;
    height: 4px;
    background: var(--gray-200);
    border-radius: 2px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary-black);
    width: 0%;
    animation: progressFill 3s ease-in-out infinite;
}

@keyframes progressFill {
    0% {
        width: 0%;
    }

    50% {
        width: 70%;
    }

    100% {
        width: 100%;
    }
}

/* ========== MOBILE MENU TOGGLE ========== */
.mobile-menu-toggle {
    position: fixed;
    top: 1rem;
    left: 1rem;
    z-index: 3000;
    background: var(--primary-white);
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    width: 50px;
    height: 50px;
    cursor: pointer;
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.mobile-menu-toggle:hover {
    border-color: var(--primary-black);
    background: var(--gray-50);
}

.menu-bar {
    width: 20px;
    height: 2px;
    background: var(--primary-black);
    transition: var(--transition);
}

/* ========== LISTINGS CONTAINER ========== */
.listings-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ========== HEADER ========== */
.listings-header {
    background: var(--primary-white);
    border-bottom: 1px solid var(--gray-200);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid var(--gray-100);
}

.logo-section {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: var(--primary-black);
}

/* Logo image proportions */
.logo-img {
    height: 36px;
    width: auto;
    border-radius: 8px;
    display: block;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: var(--primary-black);
    color: var(--primary-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.logo-text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.4rem;
    font-weight: 900;
    color: var(--primary-black);
}

.breadcrumb {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--gray-600);
}

.breadcrumb a {
    color: var(--gray-600);
    text-decoration: none;
    transition: var(--transition);
}

.breadcrumb a:hover {
    color: var(--primary-black);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-credits {
    background: var(--gray-100);
    color: var(--primary-black);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.user-credits i {
    color: var(--accent-yellow);
}

.user-avatar {
    position: relative;
    width: 40px;
    height: 40px;
}

.user-avatar img {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--gray-200);
}

.user-status {
    position: absolute;
    bottom: 0;
    right: 0;
    width: 12px;
    height: 12px;
    background: var(--accent-green);
    border: 2px solid var(--primary-white);
    border-radius: 50%;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    width: 40px;
    height: 40px;
    cursor: pointer;
    align-items: center;
    justify-content: center;
    color: var(--gray-600);
    transition: var(--transition);
}

.mobile-menu-btn:hover {
    border-color: var(--primary-black);
    color: var(--primary-black);
}

/* ========== SEARCH HERO SECTION ========== */
.search-hero {
    padding: 3rem 0;
    background: var(--primary-white);
    text-align: center;
}

.search-content {
    max-width: 800px;
    margin: 0 auto;
    margin-bottom: 3rem;
}

.search-title {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary-black);
    margin-bottom: 1rem;
    line-height: 1.2;
}

.search-subtitle {
    font-size: 1.1rem;
    color: var(--gray-600);
    margin-bottom: 2rem;
}

.search-bar-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.search-bar {
    display: flex;
    gap: 1rem;
    align-items: stretch;
}

.search-input-wrapper {
    position: relative;
    flex: 1;
}

.search-input {
    width: 100%;
    padding: 1rem 1rem 1rem 3rem;
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius-lg);
    font-size: 1rem;
    background: var(--primary-white);
    color: var(--primary-black);
    transition: var(--transition);
    outline: none;
}

.search-input:focus {
    border-color: var(--primary-black);
    box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.1);
}

.search-input::placeholder {
    color: var(--gray-400);
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-400);
    font-size: 1rem;
}

.search-clear {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--gray-400);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 50%;
    transition: var(--transition);
}

.search-clear:hover {
    background: var(--gray-100);
    color: var(--gray-600);
}

.search-btn {
    padding: 1rem 2rem;
    background: var(--primary-black);
    color: var(--primary-white);
    border: none;
    border-radius: var(--border-radius-lg);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    white-space: nowrap;
}

.search-btn:hover {
    background: var(--gray-800);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.quick-searches {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

.quick-label {
    font-size: 0.9rem;
    color: var(--gray-600);
    font-weight: 500;
}

.quick-search-tag {
    padding: 0.5rem 1rem;
    background: var(--gray-100);
    border: 2px solid var(--gray-200);
    border-radius: 20px;
    font-size: 0.85rem;
    color: var(--gray-700);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.quick-search-tag:hover {
    background: var(--primary-black);
    color: var(--primary-white);
    border-color: var(--primary-black);
}

.search-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    padding: 2rem 0;
    border-top: 1px solid var(--gray-100);
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-family: 'JetBrains Mono', monospace;
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-black);
    line-height: 1;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--gray-600);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-top: 0.25rem;
}

/* ========== MAIN CONTENT ========== */
.listings-main {
    flex: 1;
    padding: 2rem;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

.listings-content {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 2rem;
    align-items: start;
}

/* ========== FILTERS SIDEBAR ========== */
.filters-sidebar {
    background: var(--primary-white);
    border: 1px solid var(--gray-200);
    border-radius: var(--border-radius-lg);
    padding: 0;
    position: sticky;
    top: 120px;
    max-height: calc(100vh - 140px);
    overflow-y: auto;
    box-shadow: var(--shadow-sm);
}

.filters-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--gray-100);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.filters-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-black);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.filters-clear {
    background: none;
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    color: var(--gray-600);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.filters-clear:hover {
    border-color: var(--primary-black);
    color: var(--primary-black);
}

.filters-clear.has-active-filters {
    background: var(--primary-black);
    color: var(--primary-white);
    border-color: var(--primary-black);
}

.filters-clear.has-active-filters:hover {
    background: var(--gray-800);
}

.filters-content {
    padding: 0;
}

.filter-group {
    border-bottom: 1px solid var(--gray-100);
}

.filter-group:last-child {
    border-bottom: none;
}

.filter-title {
    padding: 1rem 1.5rem;
    background: var(--gray-50);
    border: none;
    width: 100%;
    text-align: left;
    font-size: 1rem;
    font-weight: 600;
    color: var(--primary-black);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.filter-title:hover {
    background: var(--gray-100);
}

.filter-title i {
    transition: var(--transition);
}

.filter-group.expanded .filter-title i {
    transform: rotate(180deg);
}

.filter-options {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.filter-group.expanded .filter-options {
    max-height: 400px;
}

.filter-option {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    border-radius: var(--border-radius);
}

.filter-option:hover {
    background: var(--gray-50);
    transform: translateX(2px);
}

.filter-option input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
}

.checkmark {
    position: relative;
    height: 18px;
    width: 18px;
    background: var(--primary-white);
    border: 2px solid var(--gray-300);
    border-radius: 4px;
    flex-shrink: 0;
    transition: var(--transition);
}

.checkmark::after {
    content: "";
    position: absolute;
    display: none;
    left: 5px;
    top: 2px;
    width: 4px;
    height: 8px;
    border: solid var(--primary-white);
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.filter-option input:checked~.checkmark {
    background: var(--primary-black);
    border-color: var(--primary-black);
    transform: scale(1.1);
}

.filter-option input:checked~.checkmark::after {
    display: block;
}

.filter-option input:checked~.option-text {
    color: var(--primary-black);
    font-weight: 600;
}

.filter-option input:checked~.option-count {
    color: var(--primary-black);
    font-weight: 600;
}

.option-text {
    flex: 1;
    font-size: 0.9rem;
    color: var(--gray-700);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.option-count {
    font-size: 0.8rem;
    color: var(--gray-500);
    font-family: 'JetBrains Mono', monospace;
    transition: var(--transition);
}

.option-count.updated {
    animation: countUpdate 0.3s ease;
}

@keyframes countUpdate {
    0% { transform: scale(1); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}

.rating-stars {
    display: flex;
    gap: 2px;
}

.rating-stars i {
    color: var(--accent-yellow);
    font-size: 0.8rem;
}

.filters-toggle {
    display: none;
    background: none;
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    padding: 0.75rem 1rem;
    font-size: 0.9rem;
    color: var(--gray-700);
    cursor: pointer;
    transition: var(--transition);
    align-items: center;
    gap: 0.5rem;
}

.filters-toggle:hover {
    border-color: var(--primary-black);
    color: var(--primary-black);
}

/* ========== PAPERS SECTION ========== */
.papers-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.papers-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 1rem;
    flex-wrap: wrap;
}

.results-info h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 0.25rem;
}

.results-info p {
    font-size: 0.9rem;
    color: var(--gray-600);
}

.papers-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.view-toggle {
    display: flex;
    background: var(--gray-100);
    border-radius: var(--border-radius);
    padding: 2px;
}

.view-btn {
    background: none;
    border: none;
    padding: 0.5rem;
    border-radius: calc(var(--border-radius) - 2px);
    cursor: pointer;
    color: var(--gray-600);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
}

.view-btn:hover,
.view-btn.active {
    background: var(--primary-black);
    color: var(--primary-white);
}

.sort-dropdown {
    position: relative;
}

.sort-btn {
    background: var(--primary-white);
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    padding: 0.75rem 1rem;
    font-size: 0.9rem;
    color: var(--gray-700);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.sort-btn:hover {
    border-color: var(--primary-black);
    color: var(--primary-black);
}

.sort-options {
    position: absolute;
    top: calc(100% + 0.5rem);
    left: 0;
    right: 0;
    background: var(--primary-white);
    border: 1px solid var(--gray-200);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    z-index: 100;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: var(--transition);
}

.sort-options.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.sort-option {
    width: 100%;
    padding: 0.75rem 1rem;
    border: none;
    background: none;
    text-align: left;
    font-size: 0.9rem;
    color: var(--gray-700);
    cursor: pointer;
    transition: var(--transition);
    border-bottom: 1px solid var(--gray-100);
}

.sort-option:last-child {
    border-bottom: none;
}

.sort-option:hover,
.sort-option.active {
    background: var(--gray-50);
    color: var(--primary-black);
}

/* ========== PAPERS GRID ========== */
.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
    animation: fadeInUp 0.6s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.papers-grid.list-view {
    grid-template-columns: 1fr;
}

.papers-grid.list-view .paper-card {
    display: grid;
    grid-template-columns: 1fr 200px;
    gap: 1rem;
    align-items: center;
    padding: 1rem;
}

.paper-card {
    background: var(--primary-white);
    border: 1px solid var(--gray-200);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    animation: slideInUp 0.4s ease;
    animation-fill-mode: both;
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.paper-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--gray-300);
}

.paper-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.paper-type {
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    background: var(--gray-100);
    color: var(--gray-700);
}

.paper-type.final {
    background: var(--accent-red);
    color: var(--primary-white);
}

.paper-type.midterm {
    background: var(--accent-blue);
    color: var(--primary-white);
}

.paper-type.quiz {
    background: var(--accent-green);
    color: var(--primary-white);
}

.paper-menu {
    background: none;
    border: none;
    color: var(--gray-400);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 4px;
    transition: var(--transition);
}

.paper-menu:hover {
    background: var(--gray-100);
    color: var(--gray-600);
}

.paper-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-black);
    margin-bottom: 1rem;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.paper-meta {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.meta-row {
    display: flex;
    gap: 1rem;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--gray-600);
    flex: 1;
}

.meta-item i {
    color: var(--gray-400);
    width: 14px;
    text-align: center;
}

.paper-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--gray-100);
}

.paper-rating {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.paper-rating i {
    color: var(--accent-yellow);
    font-size: 0.9rem;
}

.rating-stars-container {
    display: flex;
    gap: 2px;
    align-items: center;
}

.star-rating {
    transition: var(--transition);
    font-size: 0.9rem;
}

.star-rating:hover {
    transform: scale(1.2);
    color: var(--accent-yellow) !important;
}

.rating-count {
    font-size: 0.75rem;
    color: var(--gray-500);
    margin-left: 0.25rem;
}

.rating-value {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--gray-700);
    font-family: 'JetBrains Mono', monospace;
}

.paper-actions {
    display: flex;
    gap: 0.5rem;
}

.paper-action {
    width: 36px;
    height: 36px;
    background: var(--gray-100);
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    color: var(--gray-600);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.paper-action:hover {
    background: var(--gray-200);
    color: var(--primary-black);
}

.paper-action.primary {
    background: var(--primary-black);
    color: var(--primary-white);
}

.paper-action.primary:hover {
    background: var(--gray-800);
    transform: scale(1.05);
}

/* ========== PAGINATION ========== */
.pagination-container {
    margin-top: 2rem;
    display: flex;
    justify-content: center;
}

.pagination {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--primary-white);
    padding: 1rem;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--gray-200);
    box-shadow: var(--shadow-sm);
}

.page-btn {
    padding: 0.75rem 1rem;
    background: var(--primary-white);
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--gray-700);
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.page-btn:hover:not(:disabled) {
    border-color: var(--primary-black);
    background: var(--gray-50);
}

.page-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.page-numbers {
    display: flex;
    gap: 0.25rem;
}

.page-number {
    width: 40px;
    height: 40px;
    background: var(--primary-white);
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--gray-700);
    transition: var(--transition);
}

.page-number:hover {
    border-color: var(--primary-black);
    background: var(--gray-50);
}

.page-number.active {
    background: var(--primary-black);
    border-color: var(--primary-black);
    color: var(--primary-white);
}

.page-ellipsis {
    padding: 0 0.5rem;
    color: var(--gray-400);
    font-size: 0.9rem;
}

/* ========== FEATURED CATEGORIES ========== */
.featured-categories {
    background: var(--primary-white);
    padding: 4rem 2rem;
    margin-top: 4rem;
    border-top: 1px solid var(--gray-200);
}

.categories-content {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.categories-content h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 3rem;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.category-card {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.5rem;
    background: var(--gray-50);
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius-lg);
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
}

.category-card:hover {
    border-color: var(--primary-black);
    background: var(--primary-white);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.category-icon {
    width: 50px;
    height: 50px;
    background: var(--primary-black);
    color: var(--primary-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.category-info {
    flex: 1;
}

.category-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-black);
    margin-bottom: 0.25rem;
}

.category-info p {
    font-size: 0.9rem;
    color: var(--gray-500);
}

.category-arrow {
    color: var(--gray-400);
    font-size: 1rem;
    transition: var(--transition);
}

.category-card:hover .category-arrow {
    color: var(--primary-black);
    transform: translateX(4px);
}

/* ========== MODAL ========== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 3000;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.modal.show {
    display: flex;
}

.modal-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    position: relative;
    background: var(--primary-white);
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-xl);
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px) scale(0.95);
    }

    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--gray-200);
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

.modal-header h2 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--primary-black);
    line-height: 1.4;
    flex: 1;
    margin-right: 1rem;
}

.modal-close {
    width: 32px;
    height: 32px;
    background: none;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--gray-400);
    transition: var(--transition);
    flex-shrink: 0;
}

.modal-close:hover {
    background: var(--gray-100);
    color: var(--gray-600);
}

.modal-body {
    padding: 1.5rem;
}

.paper-details {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.paper-meta {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--gray-600);
}

.meta-item i {
    color: var(--gray-400);
}

.paper-description h4,
.paper-tags h4 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--primary-black);
    margin-bottom: 0.5rem;
}

.paper-description p {
    color: var(--gray-600);
    line-height: 1.6;
}

.tags-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    padding: 0.25rem 0.75rem;
    background: var(--gray-200);
    border-radius: 12px;
    font-size: 0.8rem;
    color: var(--gray-700);
}

.paper-stats {
    display: flex;
    justify-content: space-around;
    padding: 1rem;
    background: var(--gray-50);
    border-radius: var(--border-radius);
}

.stat {
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.stat i {
    color: var(--gray-400);
    font-size: 1.2rem;
}

.stat span:nth-child(2) {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary-black);
    font-family: 'JetBrains Mono', monospace;
}

.stat span:nth-child(3) {
    font-size: 0.8rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.modal-footer {
    padding: 1.5rem;
    border-top: 1px solid var(--gray-200);
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
}

/* ========== BUTTONS ========== */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    text-decoration: none;
    font-family: inherit;
    outline: none;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: var(--primary-black);
    color: var(--primary-white);
}

.btn-primary:hover {
    background: var(--gray-800);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--primary-white);
    color: var(--primary-black);
    border: 2px solid var(--gray-200);
}

.btn-secondary:hover {
    border-color: var(--primary-black);
    background: var(--gray-50);
}

/* ========== MOBILE BACKDROP ========== */
.mobile-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    z-index: 1999;
    display: none;
    opacity: 0;
    transition: var(--transition);
}

.mobile-backdrop.active {
    display: block;
    opacity: 1;
}

/* ========== TOAST NOTIFICATIONS ========== */
.toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 4000;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    max-width: 400px;
}

.toast {
    background: var(--primary-white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--gray-200);
    padding: 1rem;
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    min-width: 300px;
    animation: toastSlideIn 0.3s ease;
}

.toast.success {
    border-left: 4px solid var(--accent-green);
}

.toast.error {
    border-left: 4px solid var(--accent-red);
}

.toast.warning {
    border-left: 4px solid var(--accent-yellow);
}

.toast.info {
    border-left: 4px solid var(--accent-blue);
}

@keyframes toastSlideIn {
    from {
        opacity: 0;
        transform: translateX(100%);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.toast-icon {
    font-size: 1.2rem;
    flex-shrink: 0;
    margin-top: 0.1rem;
}

.toast.success .toast-icon {
    color: var(--accent-green);
}

.toast.error .toast-icon {
    color: var(--accent-red);
}

.toast.warning .toast-icon {
    color: var(--accent-yellow);
}

.toast.info .toast-icon {
    color: var(--accent-blue);
}

.toast-content {
    flex: 1;
}

.toast-message {
    font-size: 0.85rem;
    color: var(--gray-600);
    line-height: 1.4;
}

.toast-close {
    background: none;
    border: none;
    color: var(--gray-400);
    cursor: pointer;
    font-size: 1rem;
    padding: 0.25rem;
    border-radius: 4px;
    transition: var(--transition);
    flex-shrink: 0;
}

.toast-close:hover {
    background: var(--gray-100);
    color: var(--gray-600);
}

/* ========== EMPTY STATES ========== */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--gray-500);
    grid-column: 1 / -1;
}

.empty-icon {
    font-size: 4rem;
    color: var(--gray-300);
    margin-bottom: 1rem;
}

.empty-state h3 {
    font-size: 1.5rem;
    color: var(--gray-600);
    margin-bottom: 0.5rem;
}

.empty-state p {
    margin-bottom: 2rem;
    font-size: 1rem;
}

.papers-loader {
    grid-column: 1 / -1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 4rem;
}

.papers-loader .loader-animation {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--gray-200);
    border-top: 4px solid var(--primary-black);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

/* ========== MOBILE SECURITY & UX ========== */
/* Prevent text selection on mobile */
* {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

/* Allow text selection for specific elements */
input, textarea, .paper-title, .option-text {
    -webkit-user-select: text;
    -khtml-user-select: text;
    -moz-user-select: text;
    -ms-user-select: text;
    user-select: text;
}

/* Prevent zoom on input focus */
input[type="text"], input[type="search"], textarea {
    font-size: 16px !important;
}

/* ========== COMPREHENSIVE RESPONSIVE DESIGN ========== */

/* Large Desktop (1440px+) */
@media (min-width: 1440px) {
    .listings-main {
        padding: 2.5rem;
        max-width: 1600px;
        margin: 0 auto;
    }
    
    .papers-grid {
        grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
        gap: 2rem;
    }
    
    .search-hero {
        padding: 4rem 2.5rem;
    }
}

/* Desktop (1200px - 1439px) */
@media (max-width: 1439px) {
    .listings-main {
        padding: 2rem;
    }
    
    .papers-grid {
        grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
        gap: 1.5rem;
    }
}

/* Tablet Landscape (1024px - 1199px) */
@media (max-width: 1199px) {
    .listings-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .filters-sidebar {
        display: none;
        position: fixed;
        top: 0;
        right: 0;
        width: 320px;
        height: 100vh;
        z-index: 2000;
        overflow-y: auto;
        box-shadow: var(--shadow-xl);
    }

    .filters-sidebar.show {
        display: block;
        animation: slideInRight 0.3s ease;
    }

    @keyframes slideInRight {
        from {
            transform: translateX(100%);
            opacity: 0;
        }
        to {
            transform: translateX(0);
            opacity: 1;
        }
    }

    .filters-toggle {
        display: flex;
    }

    .search-stats {
        gap: 2rem;
        flex-wrap: wrap;
        justify-content: center;
    }

    .papers-controls {
        flex-wrap: wrap;
        gap: 0.75rem;
        justify-content: center;
    }
    
    .papers-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    }
}

/* Tablet Portrait (768px - 1023px) */
@media (max-width: 1023px) {
    .mobile-menu-btn {
        display: flex;
    }

    .header-content {
        padding: 0 1.5rem;
    }

    .listings-main {
        padding: 1.5rem;
    }
    
    .search-hero {
        padding: 3rem 1.5rem;
    }
    
    .search-title {
        font-size: 2.5rem;
        line-height: 1.1;
    }
    
    .search-subtitle {
        font-size: 1rem;
    }
    
    .search-bar {
        max-width: 500px;
    }
    
    .papers-grid {
        grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
        gap: 1.25rem;
    }
    
    .paper-card {
        padding: 1.25rem;
    }
    
    .filters-sidebar {
        width: 300px;
    }
}

/* Mobile Landscape & Large Mobile (481px - 767px) */
@media (max-width: 767px) {
    /* Prevent zoom on mobile */
    body {
        touch-action: manipulation;
        -webkit-overflow-scrolling: touch;
    }
    
    /* Adjust logo sizing on phones */
    .logo-img { 
        height: 28px; 
        border-radius: 6px; 
    }
    
    /* Prevent text selection on mobile */
    .paper-card, .category-card, .filter-option {
        -webkit-touch-callout: none;
        -webkit-user-select: none;
        user-select: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }

    .header-content {
        padding: 0 1rem;
    }

    .header-top {
        flex-direction: column;
        gap: 1rem;
        align-items: stretch;
    }

    .logo-section {
        justify-content: space-between;
        align-items: center;
    }
    
    .logo-text {
        font-size: 1.1rem;
    }

    .breadcrumb {
        display: none;
    }

    .header-actions {
        justify-content: space-between;
        width: 100%;
        gap: 0.75rem;
    }

    .search-hero {
        padding: 2.5rem 1rem;
    }

    .search-title {
        font-size: 2rem;
        line-height: 1.1;
    }

    .search-subtitle {
        font-size: 0.95rem;
    }

    .search-bar {
        flex-direction: column;
        gap: 0.75rem;
        max-width: 400px;
    }
    
    .search-input {
        padding: 0.75rem;
        font-size: 0.9rem;
    }

    .search-btn {
        width: 100%;
        justify-content: center;
        padding: 0.75rem;
    }

    .quick-searches {
        flex-direction: column;
        gap: 0.75rem;
        align-items: stretch;
    }

    .quick-search-tag {
        text-align: center;
        padding: 0.5rem 1rem;
        font-size: 0.85rem;
    }

    .search-stats {
        gap: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .stat-item {
        padding: 0.75rem;
        min-width: 120px;
        text-align: center;
    }

    .listings-main {
        padding: 1rem;
    }

    .papers-header {
        flex-direction: column;
        gap: 1rem;
        align-items: stretch;
    }

    .papers-controls {
        justify-content: space-between;
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .papers-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .paper-card {
        padding: 1rem;
    }
    
    .paper-title {
        font-size: 1rem;
        line-height: 1.3;
    }
    
    .paper-meta {
        font-size: 0.8rem;
    }
    
    .paper-stats {
        gap: 0.75rem;
    }
    
    .stat {
        font-size: 0.75rem;
    }
    
    .filters-sidebar {
        width: 100vw;
        max-width: 350px;
    }
    
    .filter-section {
        padding: 1rem;
    }
    
    .filter-section h3 {
        font-size: 1rem;
    }
    
    /* Button responsiveness */
    .btn {
        padding: 0.6rem 1rem;
        font-size: 0.85rem;
    }
    
    .btn-sm {
        padding: 0.4rem 0.75rem;
        font-size: 0.75rem;
    }
}

/* Mobile Portrait (320px - 480px) */
@media (max-width: 480px) {
    .header-content {
        padding: 0 0.75rem;
    }
    
    .logo-text {
        font-size: 1rem;
    }
    
    .search-hero {
        padding: 2rem 0.75rem;
    }
    
    .search-title {
        font-size: 1.6rem;
        line-height: 1.1;
    }

    .search-subtitle {
        font-size: 0.85rem;
    }
    
    .search-bar {
        max-width: 100%;
    }
    
    .search-input {
        padding: 0.6rem;
        font-size: 0.85rem;
    }
    
    .search-btn {
        padding: 0.6rem;
        font-size: 0.85rem;
    }
    
    .quick-search-tag {
        padding: 0.4rem 0.75rem;
        font-size: 0.8rem;
    }
    
    .stat-item {
        padding: 0.6rem;
        min-width: 100px;
        font-size: 0.8rem;
    }

    .listings-main {
        padding: 0.75rem;
    }
    
    .papers-grid {
        gap: 0.75rem;
    }
    
    .paper-card {
        padding: 0.75rem;
    }
    
    .paper-title {
        font-size: 0.9rem;
    }
    
    .paper-meta {
        font-size: 0.75rem;
    }
    
    .paper-stats {
        gap: 0.5rem;
    }
    
    .stat {
        font-size: 0.7rem;
    }

    .user-credits {
        padding: 0.25rem 0.5rem;
        font-size: 0.8rem;
    }
    
    .filters-sidebar {
        width: 100vw;
        max-width: 100vw;
    }
    
    .filter-section {
        padding: 0.75rem;
    }
    
    .filter-section h3 {
        font-size: 0.9rem;
    }
    
    .filter-option {
        padding: 0.5rem;
        font-size: 0.8rem;
    }
    
    .category-card {
        flex-direction: column;
        text-align: center;
        gap: 0.75rem;
        padding: 1rem;
    }

    .categories-content h2 {
        font-size: 1.5rem;
    }

    .modal {
        padding: 0.5rem;
    }

    .modal-content {
        max-height: 95vh;
        margin: 0;
        border-radius: 12px;
    }
    
    .modal-header {
        padding: 0.75rem;
    }
    
    .modal-title {
        font-size: 1rem;
    }
    
    .modal-body {
        padding: 0.75rem;
    }

    .modal-footer {
        flex-direction: column;
        padding: 0.75rem;
        gap: 0.5rem;
    }

    .toast-container {
        left: 0.5rem;
        right: 0.5rem;
        max-width: none;
        top: 10px;
    }

    .toast {
        min-width: auto;
        padding: 0.6rem 0.8rem;
        font-size: 0.8rem;
    }
    
    .btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.8rem;
    }
    
    .btn-sm {
        padding: 0.35rem 0.6rem;
        font-size: 0.7rem;
    }
}

/* Small Mobile (320px - 375px) */
@media (max-width: 375px) {
    .header-content {
        padding: 0 0.5rem;
    }
    
    .search-hero {
        padding: 1.5rem 0.5rem;
    }
    
    .search-title {
        font-size: 1.4rem;
    }
    
    .search-subtitle {
        font-size: 0.8rem;
    }
    
    .listings-main {
        padding: 0.5rem;
    }
    
    .paper-card {
        padding: 0.6rem;
    }
    
    .paper-title {
        font-size: 0.85rem;
    }
    
    .modal-content {
        border-radius: 8px;
    }
    
    .btn {
        padding: 0.45rem 0.6rem;
        font-size: 0.75rem;
    }
}

/* Landscape orientation fixes */
@media (max-height: 500px) and (orientation: landscape) {
    .search-hero {
        padding: 1.5rem 1rem;
    }
    
    .search-title {
        font-size: 1.8rem;
    }
    
    .modal-content {
        max-height: 85vh;
    }
    
    .filters-sidebar {
        height: 85vh;
    }
}

    .papers-grid.list-view .paper-stats {
        align-items: flex-start;
        flex-direction: row;
        justify-content: space-between;
    }

    .paper-meta {
        flex-direction: column;
        gap: 0.5rem;
    }

    .meta-row {
        justify-content: space-between;
    }

    .pagination {
        flex-wrap: wrap;
        gap: 0.25rem;
    }

    .page-btn span {
        display: none;
    }

    .categories-grid {
        grid-template-columns: 1fr;
    }

    .featured-categories {
        padding: 2rem 1rem;
    }

    .modal-header h2 {
        font-size: 1.1rem;
    }

    .paper-stats {
        flex-direction: column;
        gap: 1rem;
    }

    .stat {
        flex-direction: row;
        align-items: center;
        gap: 0.5rem;
        text-align: left;
    }
}

/* ========== UTILITY CLASSES ========== */
.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.text-center {
    text-align: center;
}

.text-ellipsis {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.word-break {
    word-wrap: break-word;
    overflow-wrap: break-word;
}

/* ========== PERFORMANCE OPTIMIZATIONS ========== */
.filters-sidebar,
.papers-section,
.modal-content {
    will-change: transform;
}

.paper-card,
.category-card,
.filter-option {
    will-change: transform, box-shadow;
}

/* ========== PRINT STYLES ========== */
@media print {

    .filters-sidebar,
    .mobile-menu-toggle,
    .mobile-backdrop,
    .search-hero,
    .papers-controls,
    .modal,
    .toast-container {
        display: none !important;
    }

    .listings-main {
        margin: 0;
        padding: 0;
    }

    .paper-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid var(--gray-300);
    }
}
/* ========== UPDATED HEADER STYLES ========== */
.listings-header {
    background: var(--primary-white);
    border-bottom: 1px solid var(--gray-200);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    padding: 1rem 0;
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
}

.header-main {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 2rem;
    margin-bottom: 1.5rem;
}

.logo-section {
    display: flex;
    align-items: center;
    gap: 2rem;
    flex-shrink: 0;
}

/* ========== INTEGRATED SEARCH BAR ========== */
.header-search {
    flex: 1;
    max-width: 600px;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.header-search .search-bar {
    display: flex;
    gap: 0.5rem;
    align-items: stretch;
}

.header-search .search-input-wrapper {
    position: relative;
    flex: 1;
}

.header-search .search-input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.5rem;
    border: 2px solid var(--gray-200);
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    background: var(--primary-white);
    color: var(--primary-black);
    transition: var(--transition);
    outline: none;
}

.header-search .search-input:focus {
    border-color: var(--primary-black);
    box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.1);
}

.header-search .search-icon {
    position: absolute;
    left: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-400);
    font-size: 0.9rem;
}

.header-search .search-clear {
    position: absolute;
    right: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--gray-400);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 50%;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.header-search .search-clear:hover {
    background: var(--gray-100);
    color: var(--gray-600);
}

.header-search .search-btn {
    padding: 0.75rem 1rem;
    background: var(--primary-black);
    color: var(--primary-white);
    border: none;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.header-search .search-btn:hover {
    background: var(--gray-800);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.header-search .search-btn:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

.header-search .search-btn.loading {
    background: var(--gray-600);
    cursor: not-allowed;
    pointer-events: none;
}

.header-search .search-btn.loading i {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.header-search .quick-searches {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.header-search .quick-label {
    font-size: 0.8rem;
    color: var(--gray-600);
    font-weight: 500;
}

.header-search .quick-search-tag {
    padding: 0.25rem 0.75rem;
    background: var(--gray-100);
    border: 1px solid var(--gray-200);
    border-radius: 15px;
    font-size: 0.8rem;
    color: var(--gray-700);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.header-search .quick-search-tag:hover {
    background: var(--primary-black);
    color: var(--primary-white);
    border-color: var(--primary-black);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

/* ========== WELCOME SECTION (Simplified) ========== */
.welcome-section {
    text-align: center;
    padding: 1rem 0;
    border-top: 1px solid var(--gray-100);
}

.welcome-section h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 0.5rem;
}

.welcome-section p {
    font-size: 1rem;
    color: var(--gray-600);
}

/* ========== REMOVE OLD SEARCH HERO ========== */
.search-hero {
    display: none;
}

/* ========== UPDATED LOADING SCREEN ========== */
.loader-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-black);
    color: var(--primary-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.05);
    }
}

/* ========== PAPER PREVIEW MODAL ========== */
.paper-preview-modal .modal-content {
    max-width: 90vw;
    max-height: 95vh;
    width: 1000px;
}

.paper-preview-container {
    width: 100%;
    height: 70vh;
    background: var(--gray-50);
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.paper-preview-container iframe {
    width: 100%;
    height: 100%;
    border: none;
    border-radius: var(--border-radius);
}

.preview-placeholder {
    text-align: center;
    color: var(--gray-500);
    padding: 2rem;
}

.preview-placeholder i {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--gray-300);
}

/* ========== RESPONSIVE UPDATES ========== */
@media (max-width: 1024px) {
    .header-main {
        flex-direction: column;
        gap: 1rem;
        align-items: stretch;
    }

    .header-search {
        max-width: none;
    }

    .header-search .search-bar {
        flex-direction: column;
        gap: 0.5rem;
    }

    .header-search .search-btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .header-content {
        padding: 0 1rem;
    }

    .logo-section {
        gap: 1rem;
    }

    .breadcrumb {
        display: none;
    }

    .header-search .quick-searches {
        justify-content: center;
    }

    .welcome-section h1 {
        font-size: 1.5rem;
    }

    .welcome-section p {
        font-size: 0.9rem;
    }

    .paper-preview-modal .modal-content {
        max-width: 95vw;
        width: auto;
    }

    .paper-preview-container {
        height: 60vh;
    }
}