/**
 * Question Bank Portal - Main Styles
 */

/* Header */
.site-header {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-primary);
    padding: var(--space-3) 0;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--text-primary);
}

.logo-icon {
    font-size: var(--font-size-2xl);
}

.logo-text span {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.header-search {
    flex: 1;
    max-width: 500px;
    display: flex;
    align-items: center;
    background: var(--bg-elevated);
    border-radius: var(--radius-full);
    border: 1px solid var(--border-primary);
    overflow: hidden;
}

.header-search:focus-within {
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.15);
}

.header-search input {
    flex: 1;
    border: none;
    background: transparent;
    padding: var(--space-3) var(--space-4);
    font-size: var(--font-size-sm);
    color: var(--text-primary);
}

.header-search input:focus {
    outline: none;
}

.header-search button {
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: var(--space-3) var(--space-4);
    cursor: pointer;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-primary);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-lg);
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    background: var(--bg-elevated);
    color: var(--primary-500);
}

/* Hero */
.hero {
    background: var(--gradient-hero);
    padding: var(--space-16) 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none'%3E%3Cg fill='%23fff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'%3E%3C/path%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: var(--font-size-5xl);
    font-weight: 800;
    color: white;
    margin-bottom: var(--space-4);
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.hero p {
    font-size: var(--font-size-xl);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--space-8);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-search {
    max-width: 600px;
    margin: 0 auto var(--space-8);
    display: flex;
    background: white;
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-2xl);
    overflow: hidden;
}

.hero-search input {
    flex: 1;
    padding: var(--space-5) var(--space-6);
    border: none;
    font-size: var(--font-size-lg);
}

.hero-search input:focus {
    outline: none;
}

.hero-search button {
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: var(--space-5) var(--space-8);
    font-size: var(--font-size-lg);
    font-weight: 600;
    cursor: pointer;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-8);
    flex-wrap: wrap;
}

.hero-stat {
    text-align: center;
    color: white;
}

.hero-stat-value {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    display: block;
}

.hero-stat-label {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

/* Main Layout */
.main-content {
    padding: var(--space-8) 0;
}

.content-grid {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: var(--space-6);
}

@media (max-width: 1024px) {
    .content-grid {
        grid-template-columns: 1fr;
    }
}

/* Section Headers */
.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-4);
}

.section-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.section-title-icon {
    font-size: var(--font-size-2xl);
}

/* Branch Cards */
.branch-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: var(--space-3);
}

.branch-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-xl);
    padding: var(--space-4);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-normal);
    text-decoration: none;
    color: var(--text-primary);
}

.branch-card:hover {
    border-color: var(--primary-400);
    background: var(--primary-50);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

[data-theme="dark"] .branch-card:hover {
    background: var(--bg-tertiary);
}

.branch-card.active {
    border-color: var(--primary-500);
    background: var(--primary-100);
}

.branch-icon {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--space-2);
}

.branch-name {
    font-weight: 600;
    font-size: var(--font-size-sm);
    margin-bottom: var(--space-1);
}

.branch-count {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

/* Semester Tabs */
.semester-tabs {
    display: flex;
    gap: var(--space-2);
    flex-wrap: wrap;
    margin-bottom: var(--space-4);
}

.semester-tab {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-lg);
    background: var(--bg-elevated);
    border: 1px solid var(--border-primary);
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.semester-tab:hover {
    border-color: var(--primary-400);
    color: var(--primary-600);
}

.semester-tab.active {
    background: var(--gradient-primary);
    color: white;
    border-color: transparent;
    box-shadow: var(--shadow-glow);
}

/* Paper List */
.paper-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.paper-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-xl);
    padding: var(--space-4);
    display: flex;
    align-items: center;
    gap: var(--space-4);
    transition: all var(--transition-normal);
}

.paper-card:hover {
    border-color: var(--primary-300);
    box-shadow: var(--shadow-md);
}

.paper-icon {
    width: 48px;
    height: 48px;
    background: var(--error-50);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-2xl);
    flex-shrink: 0;
}

.paper-info {
    flex: 1;
    min-width: 0;
}

.paper-title {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-1);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.paper-meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.paper-actions {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.btn-download {
    background: var(--gradient-success);
    color: white;
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-lg);
    font-weight: 600;
    font-size: var(--font-size-sm);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: var(--space-2);
    transition: all var(--transition-fast);
}

.btn-download:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    color: white;
}

/* Sidebar */
.sidebar {
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
}

.sidebar-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-xl);
    overflow: hidden;
}

.sidebar-card-header {
    background: var(--gradient-primary);
    color: white;
    padding: var(--space-4);
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.sidebar-card-body {
    padding: var(--space-4);
}

/* Popular */
.popular-list {
    list-style: none;
}

.popular-item {
    padding: var(--space-3) 0;
    border-bottom: 1px solid var(--border-secondary);
}

.popular-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.popular-item:first-child {
    padding-top: 0;
}

.popular-link {
    display: flex;
    align-items: flex-start;
    gap: var(--space-3);
    color: var(--text-primary);
    text-decoration: none;
}

.popular-link:hover {
    color: var(--primary-600);
}

.popular-rank {
    width: 24px;
    height: 24px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-xs);
    font-weight: 700;
    color: var(--text-muted);
    flex-shrink: 0;
}

.popular-item:nth-child(1) .popular-rank {
    background: linear-gradient(135deg, #FFD700, #FFA500);
    color: white;
}

.popular-item:nth-child(2) .popular-rank {
    background: linear-gradient(135deg, #C0C0C0, #A0A0A0);
    color: white;
}

.popular-item:nth-child(3) .popular-rank {
    background: linear-gradient(135deg, #CD7F32, #8B4513);
    color: white;
}

.popular-title {
    font-size: var(--font-size-sm);
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.popular-meta {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

/* Year Filter */
.year-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-2);
}

.year-btn {
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
    border: none;
    font-weight: 500;
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.year-btn:hover {
    background: var(--primary-100);
    color: var(--primary-700);
}

.year-btn.active {
    background: var(--gradient-primary);
    color: white;
}

/* Loading */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-8);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-primary);
    border-top-color: var(--primary-500);
    border-radius: var(--radius-full);
    animation: spin 1s linear infinite;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: var(--space-12);
    color: var(--text-secondary);
}

.empty-state-icon {
    font-size: 4rem;
    margin-bottom: var(--space-4);
    opacity: 0.5;
}

.empty-state h3 {
    margin-bottom: var(--space-2);
    color: var(--text-primary);
}

/* Footer */
.site-footer {
    background: var(--bg-elevated);
    border-top: 1px solid var(--border-primary);
    padding: var(--space-8) 0;
    margin-top: var(--space-12);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-4);
}

.footer-links {
    display: flex;
    gap: var(--space-6);
}

.footer-links a {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

.footer-copy {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
}

/* Mobile Nav */
.mobile-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    border-top: 1px solid var(--border-primary);
    padding: var(--space-2) var(--space-4);
    display: none;
    z-index: var(--z-fixed);
}

@media (max-width: 768px) {
    .mobile-nav {
        display: flex;
        justify-content: space-around;
    }

    .site-footer {
        padding-bottom: calc(var(--space-8) + 60px);
    }
}

.mobile-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-1);
    color: var(--text-secondary);
    text-decoration: none;
    font-size: var(--font-size-xs);
    padding: var(--space-2);
}

.mobile-nav-item.active {
    color: var(--primary-600);
}

.mobile-nav-icon {
    font-size: var(--font-size-xl);
}