/* STA-119 Course Page - Matching Global Website Theme */
:root {
  --bg-primary: #0a0a0a;
  --bg-secondary: #181a20;
  --bg-tertiary: #23272f;
  --bg-card: #181a20;
  --bg-light: #23272f;
  --bg-hover: #23272f;
  --text-primary: #fff;
  --text-secondary: #e0e0e0;
  --text-muted: #b0b0b0;
  --accent-primary: #00bfff;
  --accent-secondary: #0099cc;
  --accent-tertiary: #005577;
  --border-color: #23272f;
  --border-light: #2c2f36;
  --shadow-color: rgba(0,0,0,0.5);
  --shadow-card: 0 8px 32px rgba(0,0,0,0.3);
  --shadow-hover: 0 12px 40px rgba(0,0,0,0.4);
  --glass-bg: rgba(31,31,31,0.95);
  --glass-border: rgba(0,191,255,0.1);
  --hover-bg: rgba(0,191,255,0.08);
  --navbar-bg: rgba(10,10,10,0.98);
  --navbar-text: #fff;
  --navbar-text-hover: #00bfff;
  --transition-speed: 0.3s;
  --transition-timing: cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.7;
    color: var(--text-primary);
    background: var(--bg-primary);
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 1;
}

/* Navigation */
.nav-bar {
    background: rgba(15, 18, 25, 0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1.5px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 1.1rem 0;
    box-shadow: 0 4px 24px rgba(0,0,0,0.18);
    transition: background 0.3s, box-shadow 0.3s;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-primary);
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    color: var(--navbar-text);
    text-decoration: none;
    font-weight: 500;
    transition: all var(--transition-speed) var(--transition-timing);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.05rem;
    padding: 0.6rem 1.1rem;
    border-radius: 7px;
    position: relative;
}

.nav-link::after {
    content: '';
    display: block;
    position: absolute;
    left: 0; 
    bottom: 0;
    width: 0; 
    height: 2px;
    background: var(--accent-primary);
    transition: width var(--transition-speed) var(--transition-timing);
}

.nav-link:hover, .nav-link.active {
    color: var(--accent-primary);
    background: var(--bg-light);
}

.nav-link:hover::after, .nav-link.active::after {
    width: 100%;
}

.nav-link i {
    font-size: 0.8rem;
}

/* Header */
.header {
    background: var(--gradient-hero);
    color: var(--text-primary);
    padding: 2rem 0;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.site-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-family: 'Georgia', 'Times New Roman', serif;
    position: relative;
}

.site-title::after {
    content: ''; 
    display: block; 
    width: 80px; 
    height: 3px; 
    background: var(--accent-primary); 
    margin: 1rem auto 0; 
    border-radius: 2px;
}

.site-subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
    font-weight: 300;
    color: var(--text-secondary);
    font-family: 'Georgia', 'Times New Roman', serif;
}

/* Main Content */
.main-content {
    padding: 2rem 0;
    background-color: var(--bg-primary);
}

/* Session Information */
.session-info {
    margin-bottom: 2rem;
}

.session-info h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    text-align: center;
    font-family: 'Georgia', 'Times New Roman', serif;
    position: relative;
}

.session-info h2::after {
    content: ''; 
    display: block; 
    width: 80px; 
    height: 3px; 
    background: var(--accent-primary); 
    margin: 1rem auto 0; 
    border-radius: 2px;
}

.timing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.timing-card {
    background: var(--bg-card);
    padding: 1.2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-card);
    text-align: center;
    transition: all var(--transition-speed) var(--transition-timing);
    border: 1.5px solid var(--border-color);
}

.timing-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
    border-color: var(--accent-primary);
}

.timing-card h3 {
    color: var(--accent-primary);
    margin-bottom: 0.5rem;
    font-size: 1rem;
    font-weight: 700;
}

.timing-card p {
    margin-bottom: 0.25rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.location {
    font-weight: 600;
    color: var(--text-primary) !important;
}

/* General Resources */
.general-resources {
    margin-bottom: 2rem;
}

.general-resources h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    text-align: center;
    font-family: 'Georgia', 'Times New Roman', serif;
    position: relative;
}

.general-resources h2::after {
    content: ''; 
    display: block; 
    width: 80px; 
    height: 3px; 
    background: var(--accent-primary); 
    margin: 1rem auto 0; 
    border-radius: 2px;
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 0.8rem;
}

.resource-card {
    background: var(--bg-card);
    padding: 0.8rem;
    border-radius: 8px;
    box-shadow: var(--shadow-card);
    text-align: center;
    transition: all var(--transition-speed) var(--transition-timing);
    cursor: pointer;
    border: 1px solid var(--border-color);
}

.resource-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
    border-color: var(--accent-primary);
}

.resource-card i {
    font-size: 1.5rem;
    color: var(--accent-primary);
    margin-bottom: 0.4rem;
}

.resource-card h3 {
    font-size: 0.8rem;
    color: var(--text-primary);
    margin-bottom: 0.4rem;
    font-weight: 600;
}

.resource-card small {
    color: var(--text-muted);
    font-size: 0.75rem;
}

/* Search and Filter Section */
.search-filter-section {
    margin-bottom: 2rem;
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: 12px;
    border: 1.5px solid var(--border-color);
    box-shadow: var(--shadow-card);
}

.search-container {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.search-box {
    flex: 1;
    min-width: 300px;
    position: relative;
    display: flex;
    align-items: center;
}

.search-box i {
    position: absolute;
    left: 12px;
    color: var(--text-muted);
    z-index: 1;
}

.search-box input {
    width: 100%;
    padding: 12px 40px 12px 40px;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: all var(--transition-speed) var(--transition-timing);
    font-family: 'Georgia', 'Times New Roman', serif;
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(0,191,255,0.1);
}

.search-box input::placeholder {
    color: var(--text-muted);
}

.clear-btn {
    position: absolute;
    right: 8px;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: all var(--transition-speed) var(--transition-timing);
    display: none;
}

.clear-btn:hover {
    color: var(--text-primary);
    background: var(--bg-hover);
}

.clear-btn.show {
    display: block;
}

.filter-options {
    display: flex;
    gap: 0.75rem;
    align-items: center;
}

.sort-select {
    padding: 10px 12px;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-speed) var(--transition-timing);
    font-family: 'Georgia', 'Times New Roman', serif;
}

.sort-select:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.sort-select option {
    background: var(--bg-light);
    color: var(--text-primary);
}

.filter-toggle {
    padding: 10px 16px;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-speed) var(--transition-timing);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: 'Georgia', 'Times New Roman', serif;
}

.filter-toggle:hover {
    background: var(--bg-hover);
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.search-results-info {
    margin-top: 1rem;
    padding: 0.75rem;
    background: var(--bg-light);
    border-radius: 6px;
    color: var(--text-muted);
    font-size: 0.9rem;
    border: 1px solid var(--border-color);
}

.search-results-info span {
    color: var(--accent-primary);
    font-weight: 600;
}

/* Semester Sections */
.semester-sections {
    margin-bottom: 3rem;
}

.semester-tabs {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
    gap: 1rem;
}

.tab-btn {
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: all var(--transition-speed) var(--transition-timing);
    color: var(--text-primary);
    font-family: 'Georgia', 'Times New Roman', serif;
}

.tab-btn.active {
    background: var(--accent-primary);
    color: var(--bg-card);
    border-color: var(--accent-primary);
}

.tab-btn:hover:not(.active) {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: var(--bg-card);
}

.semester-content {
    margin-top: 2rem;
}

.semester-panel {
    display: none;
}

.semester-panel.active {
    display: block;
}

.semester-panel h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    text-align: center;
    font-family: 'Georgia', 'Times New Roman', serif;
    position: relative;
}

.semester-panel h2::after {
    content: ''; 
    display: block; 
    width: 80px; 
    height: 3px; 
    background: var(--accent-primary); 
    margin: 1rem auto 0; 
    border-radius: 2px;
}

.sessions-grid {
    display: grid;
    gap: 1rem;
}

.session-card {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-card);
    transition: all var(--transition-speed) var(--transition-timing);
    border: 1px solid var(--border-color);
}

.session-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
    border-color: var(--accent-primary);
}

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

.session-date {
    font-weight: 600;
    color: var(--accent-primary);
    font-size: 1.1rem;
}

.session-title {
    font-weight: 500;
    color: var(--text-primary);
    flex: 1;
    min-width: 200px;
    font-family: 'Georgia', 'Times New Roman', serif;
}

.session-files {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.file-link {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.5rem 0.75rem;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-primary);
    font-size: 0.9rem;
    transition: all var(--transition-speed) var(--transition-timing);
    font-family: 'Georgia', 'Times New Roman', serif;
}

.file-link:hover {
    background: var(--accent-primary);
    color: var(--bg-card);
    border-color: var(--accent-primary);
}

.file-link i {
    font-size: 0.8rem;
}

/* Footer */
.footer {
    background: var(--bg-card);
    color: var(--text-secondary);
    padding: 3rem 0 1rem;
    margin-top: 3rem;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3 {
    color: var(--accent-primary);
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    font-family: 'Georgia', 'Times New Roman', serif;
}

.footer-section h4 {
    color: var(--text-primary);
    font-size: 1.1rem;
    margin-bottom: 1rem;
    font-family: 'Georgia', 'Times New Roman', serif;
}

.footer-section p {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color var(--transition-speed) var(--transition-timing);
}

.footer-section a:hover {
    color: var(--accent-primary);
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 0.5rem;
}

.social-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: var(--bg-light);
    border-radius: 8px;
    transition: all var(--transition-speed) var(--transition-timing);
    border: 1px solid var(--border-color);
}

.social-link:hover {
    background: var(--bg-hover);
    border-color: var(--accent-primary);
    transform: translateY(-2px);
}

.social-link i {
    font-size: 1.2rem;
    color: var(--text-primary);
}

.social-link:hover i {
    color: var(--accent-primary);
}

.footer-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    padding: 0.5rem 0;
}

.footer-link i {
    font-size: 0.9rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .site-title {
        font-size: 2rem;
    }
    
    .timing-grid {
        grid-template-columns: 1fr;
    }
    
    .resources-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }
    
    .semester-tabs {
        flex-direction: column;
        align-items: center;
    }
    
    .session-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .session-files {
        width: 100%;
    }
    
    .nav-container {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-links {
        gap: 1rem;
    }

    /* Search and Filter Responsive */
    .search-container {
        flex-direction: column;
        align-items: stretch;
    }
    
    .search-box {
        min-width: auto;
    }
    
    .filter-options {
        justify-content: space-between;
    }
    
    .sort-select {
        flex: 1;
        margin-right: 0.5rem;
    }
    
    .filter-toggle {
        white-space: nowrap;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .site-title {
        font-size: 1.8rem;
    }
    
    .timing-card,
    .session-card {
        padding: 1rem;
    }
}

/* Loading Animation */
.loading {
    text-align: center;
    padding: 2rem;
    color: var(--accent-primary);
}

.loading::after {
    content: '';
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--border-color);
    border-top: 3px solid var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-left: 10px;
}

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}