/* IACL-32 Conference Website - Main Stylesheet */
/* Modern, Professional Academic Conference Design */

:root {
    /* Primary Colors - Deep Academic Blue & Gold Accents */
    --primary-color: #1a365d;
    --primary-dark: #0f2341;
    --primary-light: #2c5282;
    --accent-color: #c9a227;
    --accent-light: #e6c65c;
    
    /* Neutral Colors */
    --text-dark: #1a202c;
    --text-medium: #4a5568;
    --text-light: #718096;
    --bg-white: #ffffff;
    --bg-light: #f7fafc;
    --bg-gray: #edf2f7;
    --border-color: #e2e8f0;
    
    /* Typography */
    --font-primary: 'Noto Sans SC', 'Segoe UI', system-ui, -apple-system, sans-serif;
    --font-heading: 'Playfair Display', 'Noto Serif SC', Georgia, serif;
    --font-mono: 'Fira Code', 'Consolas', monospace;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.15);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
    --transition-slow: 500ms ease;
    
    /* Header Height */
    --header-height: 80px;
    --header-height-mobile: 28px;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-dark);
    background-color: var(--bg-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.3;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
    color: var(--text-medium);
}

a {
    color: var(--primary-light);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--accent-color);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.container-wide {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Header */
.site-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: var(--bg-white);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    box-shadow: var(--shadow-lg);
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

/* Compact Header */
.header-compact {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.site-brand {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--bg-white);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.site-brand:hover {
    color: var(--accent-light);
}

.header-compact .university-link {
    display: flex;
    align-items: center;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.8125rem;
    transition: color var(--transition-fast);
}

.header-compact .university-link:hover {
    color: var(--bg-white);
}

.header-compact .university-link i {
    margin-right: var(--spacing-xs);
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.language-switcher {
    display: flex;
    gap: var(--spacing-sm);
}

.language-switcher a {
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    transition: all var(--transition-fast);
}

.language-switcher a:hover,
.language-switcher a.active {
    color: var(--bg-white);
    background: rgba(255, 255, 255, 0.15);
}

.university-link a {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.university-link a:hover {
    color: var(--bg-white);
}

.university-link i {
    margin-right: var(--spacing-xs);
}

/* Navigation */
.main-nav {
    background: var(--primary-dark);
}

.nav-list {
    display: flex;
    justify-content: center;
    list-style: none;
    gap: var(--spacing-xs);
}

.nav-list a {
    display: block;
    padding: var(--spacing-md) var(--spacing-lg);
    color: rgba(255, 255, 255, 0.9);
    font-weight: 500;
    font-size: 0.9375rem;
    transition: all var(--transition-fast);
    position: relative;
}

.nav-list a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 3px;
    background: var(--accent-color);
    transition: all var(--transition-normal);
    transform: translateX(-50%);
}

.nav-list a:hover,
.nav-list a.active {
    color: var(--bg-white);
    background: rgba(255, 255, 255, 0.1);
}

.nav-list a:hover::after,
.nav-list a.active::after {
    width: 60%;
}

/* Mobile Navigation */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--bg-white);
    font-size: 1.5rem;
    cursor: pointer;
    padding: var(--spacing-sm);
}

@media (max-width: 968px) {
    .mobile-menu-toggle {
        display: block;
    }
    
    .main-nav {
        position: relative;
    }
    
    .nav-list {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--primary-dark);
        box-shadow: var(--shadow-lg);
        z-index: 100;
    }
    
    .nav-list.active {
        display: flex;
    }
    
    .nav-list a {
        padding: var(--spacing-md) var(--spacing-lg);
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }
    
    .header-compact .university-link span {
        display: none;
    }
    
    .header-left {
        gap: var(--spacing-sm);
    }
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, rgba(26, 54, 93, 0.65) 0%, rgba(15, 35, 65, 0.7) 100%),
                url('../images/banner.jpg') center center / cover no-repeat;
    color: var(--bg-white);
    padding: var(--spacing-3xl) 0;
    margin-top: var(--header-height); /* Space for fixed header */
    text-align: center;
    position: relative;
    overflow: hidden;
    min-height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="40" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="0.5"/></svg>');
    background-size: 100px 100px;
    opacity: 0.3;
}

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

.hero h1 {
    color: var(--bg-white);
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-lg);
    color: rgba(255, 255, 255, 0.9);
}

.hero-meta {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-xl);
}

.hero-meta-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.125rem;
}

.hero-meta-item i {
    font-size: 1.25rem;
    color: var(--accent-color);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* Page Banner - Inner Pages */
.page-banner {
    background: linear-gradient(135deg, rgba(26, 54, 93, 0.68) 0%, rgba(15, 35, 65, 0.72) 100%),
                url('../images/banner.jpg') center center / cover no-repeat;
    color: var(--bg-white);
    padding: var(--spacing-2xl) 0;
    margin-top: var(--header-height); /* Space for fixed header */
    text-align: center;
    position: relative;
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.page-banner h1 {
    color: var(--bg-white);
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.page-banner-subtitle {
    font-size: 1.125rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 0;
}

/* Mobile header height adjustment */
@media (max-width: 968px) {
    .hero,
    .page-banner {
        margin-top: var(--header-height-mobile);
    }
}

/* Notice Banner */
.notice-banner {
    background: linear-gradient(135deg, #fff3cd 0%, #ffeeba 100%);
    padding: var(--spacing-xl) 0;
    animation: slideDown 0.5s ease-out;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.notice-card {
    max-width: 900px;
    margin: 0 auto;
    background: var(--bg-white);
    border-left: 4px solid var(--warning-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.notice-title {
    color: var(--warning-color);
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.notice-title i {
    font-size: 1.75rem;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
}

.notice-content p {
    margin-bottom: 0;
    color: var(--text-dark);
    font-size: 1.05rem;
    line-height: 1.7;
}

/* Mobile responsive */
@media (max-width: 768px) {
    .notice-banner {
        padding: var(--spacing-lg) 0;
    }
    
    .notice-card {
        padding: var(--spacing-lg);
    }
    
    .notice-title {
        font-size: 1.25rem;
    }
    
    .notice-title i {
        font-size: 1.5rem;
    }
    
    .notice-content p {
        font-size: 0.95rem;
    }
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 2px solid transparent;
    text-decoration: none;
}

.btn-primary {
    background: var(--accent-color);
    color: var(--primary-dark);
}

.btn-primary:hover {
    background: var(--accent-light);
    color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background: transparent;
    color: var(--bg-white);
    border-color: var(--bg-white);
}

.btn-outline:hover {
    background: var(--bg-white);
    color: var(--primary-color);
}

.btn-secondary {
    background: var(--primary-light);
    color: var(--bg-white);
}

.btn-secondary:hover {
    background: var(--primary-color);
}

/* Sections */
.section {
    padding: var(--spacing-3xl) 0;
}

.section-light {
    background: var(--bg-light);
}

.section-gray {
    background: var(--bg-gray);
}

.section-dark {
    background: var(--primary-color);
    color: var(--bg-white);
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.section-title h2 {
    display: inline-block;
    position: relative;
    padding-bottom: var(--spacing-md);
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: var(--accent-color);
    border-radius: 2px;
}

/* Cards */
.card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: var(--spacing-xl);
    transition: all var(--transition-normal);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.card-title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-md);
}

.card-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    color: var(--bg-white);
    font-size: 1.5rem;
}

/* Grid Layouts */
.grid {
    display: grid;
    gap: var(--spacing-xl);
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 992px) {
    .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

/* Important Dates Box */
.dates-box {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    color: var(--bg-white);
}

.dates-box h3 {
    color: var(--bg-white);
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.date-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.date-item:last-child {
    border-bottom: none;
}

.date-label {
    font-weight: 500;
}

.date-value {
    background: var(--accent-color);
    color: var(--primary-dark);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-sm);
    font-weight: 600;
}

/* Info Cards Grid */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
}

/* Accordion */
.accordion {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.accordion-item {
    border-bottom: 1px solid var(--border-color);
}

.accordion-item:last-child {
    border-bottom: none;
}

.accordion-header {
    background: var(--bg-light);
    padding: var(--spacing-lg);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    transition: all var(--transition-fast);
}

.accordion-header:hover {
    background: var(--bg-gray);
}

.accordion-header i {
    transition: transform var(--transition-normal);
}

.accordion-item.active .accordion-header i {
    transform: rotate(180deg);
}

.accordion-content {
    padding: 0 var(--spacing-lg);
    max-height: 0;
    overflow: hidden;
    transition: all var(--transition-normal);
}

.accordion-item.active .accordion-content {
    padding: var(--spacing-lg);
    max-height: 2000px;
}

/* Tables */
.table-responsive {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: var(--spacing-lg);
}

th, td {
    padding: var(--spacing-md);
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background: var(--primary-color);
    color: var(--bg-white);
    font-weight: 600;
}

tr:hover {
    background: var(--bg-light);
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--text-dark);
}

.form-input,
.form-textarea,
.form-select {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
    outline: none;
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(44, 82, 130, 0.1);
}

.form-textarea {
    min-height: 150px;
    resize: vertical;
}

/* Contact Form */
.contact-form {
    background: var(--bg-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

/* Form Messages */
.form-message {
    margin-bottom: var(--spacing-lg);
}

.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.alert i {
    font-size: 1.25rem;
    flex-shrink: 0;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-warning {
    background: #fff3cd;
    color: #856404;
    border: 1px solid #ffeeba;
}

.alert-info {
    background: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

.form-input.error,
.form-textarea.error,
.form-select.error {
    border-color: #dc3545;
}

/* Footer */
.site-footer {
    background: var(--primary-dark);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

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

.footer-section h4 {
    color: var(--bg-white);
    margin-bottom: var(--spacing-lg);
    font-size: 1.125rem;
}

.footer-section p,
.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: var(--spacing-sm);
    display: block;
}

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

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-lg);
    text-align: center;
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.6);
}

/* Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.highlight {
    color: var(--accent-color);
    font-weight: 600;
}

.badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--accent-color);
    color: var(--primary-dark);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

/* Alert Boxes */
.alert {
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
}

.alert-info {
    background: #e3f2fd;
    border-left: 4px solid #2196f3;
    color: #1565c0;
}

.alert-warning {
    background: #fff3e0;
    border-left: 4px solid #ff9800;
    color: #e65100;
}

.alert-success {
    background: #e8f5e9;
    border-left: 4px solid #4caf50;
    color: #2e7d32;
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: var(--bg-white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-fast);
    z-index: 999;
}

.back-to-top:hover {
    background: var(--accent-color);
    transform: translateY(-3px);
}

.back-to-top.visible {
    display: flex;
}

/* Speaker Cards */
.speaker-card {
    text-align: center;
    padding: var(--spacing-xl);
}

.speaker-image {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: var(--spacing-lg);
    border: 4px solid var(--accent-color);
}

.speaker-name {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xs);
}

.speaker-affiliation {
    color: var(--text-light);
    font-size: 0.9375rem;
}

/* Timeline */
.timeline {
    position: relative;
    padding-left: 30px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--primary-light);
}

.timeline-item {
    position: relative;
    padding-bottom: var(--spacing-xl);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -34px;
    top: 5px;
    width: 12px;
    height: 12px;
    background: var(--accent-color);
    border-radius: 50%;
    border: 3px solid var(--bg-white);
    box-shadow: var(--shadow-sm);
}

.timeline-date {
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
}

/* Responsive Typography */
@media (max-width: 768px) {
    html { font-size: 14px; }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.375rem; }
    
    .hero h1 { font-size: 2.25rem; }
    .hero-subtitle { font-size: 1.25rem; }
    
    .hero-meta {
        flex-direction: column;
        gap: var(--spacing-md);
    }
}

/* Print Styles */
@media print {
    .site-header,
    .site-footer,
    .back-to-top,
    .mobile-menu-toggle {
        display: none !important;
    }
    
    .hero,
    .page-banner {
        margin-top: 0 !important;
        background: var(--bg-gray) !important;
        color: var(--text-dark) !important;
    }
    
    .hero h1 {
        color: var(--primary-color) !important;
    }
}