/* Base Styles & Variables */
:root {
    --primary-color: #0366d6;
    --primary-hover: #0056b3;
    --text-main: #24292e;
    --text-muted: #586069;
    --bg-main: #ffffff;
    --bg-muted: #f6f8fa;
    --border-color: #e1e4e8;
    --radius: 8px;
    --transition: all 0.2s ease-in-out;
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 70px; /* Offset for sticky navbar */
}

body {
    font-family: var(--font-main);
    color: var(--text-main);
    line-height: 1.6;
    background-color: var(--bg-main);
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Typography */
h1, h2, h3 {
    font-weight: 600;
    line-height: 1.25;
    margin-bottom: 16px;
}

.section-title {
    font-size: clamp(1.3rem, 4vw, 2rem);
    text-align: center;
    margin-bottom: 8px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-muted);
    margin-bottom: 32px;
    font-size: 1.1rem;
}

/* Utilities */
.mt-2 { margin-top: 1rem; }
.mt-4 { margin-top: 2rem; }
.grey-bg { background-color: var(--bg-muted); }

/* Layouts */
.section {
    padding: 60px 0;
    border-bottom: 1px solid var(--border-color);
}

.layout-2-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

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

/* Hero Section */
.hero {
    padding: 80px 0 60px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.paper-title {
    font-size: clamp(1.5rem, 5vw, 2.5rem);
    margin-bottom: 16px;
    color: #1a1a1a;
}

.venue {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    color: var(--primary-color);
    margin-bottom: 32px;
}

.authors {
    font-size: clamp(1rem, 2.5vw, 1.2rem);
    margin-bottom: 16px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
}

.author {
    font-weight: 500;
}
.author a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}
.author a:hover {
    text-decoration: underline;
    color: var(--primary-hover);
}

.affiliations {
    font-size: 1rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

/* Buttons */
.action-badges {
    display: flex;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius);
    text-decoration: none;
    font-weight: 500;
    font-size: 1rem;
    transition: var(--transition);
    cursor: pointer;
}

.btn-outline {
    background-color: var(--bg-main);
    color: var(--text-main);
    border: 2px solid var(--border-color);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    font-weight: 600;
}

.btn-outline:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border: 2px solid var(--primary-color);
    box-shadow: 0 4px 6px rgba(3, 102, 214, 0.2);
    font-weight: 600;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(3, 102, 214, 0.3);
}

/* Placeholders (For Video/Images) */
.placeholder-box {
    background-color: #e9ecef;
    border: 2px dashed #ced4da;
    border-radius: var(--radius);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-weight: 500;
    width: 100%;
}

.large-placeholder {
    height: 400px;
    margin-bottom: 16px;
}

.video-embed-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 Aspect Ratio */
    height: 0;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}
.video-embed-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

.caption {
    font-size: 0.9rem;
    color: var(--text-muted);
    text-align: center;
    margin-bottom: 24px;
}

/* Methodology */
.method-text ul {
    list-style-type: disc;
    padding-left: 24px;
    margin-top: 16px;
}
.method-text li {
    margin-bottom: 12px;
}

/* Audio Grids */
.audio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
    margin-top: 24px;
}

.audio-card {
    background: var(--bg-main);
    padding: 16px;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}

.audio-card span, .audio-card h3 {
    font-size: 0.95rem;
    font-weight: 600;
}

.audio-card.highlighted {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 1px var(--primary-color);
    background-color: #f0f7ff;
}

audio {
    width: 100%;
    height: 36px;
}

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

.data-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 24px;
    background: var(--bg-main);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.data-table th, .data-table td {
    padding: 12px 16px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.data-table th {
    background-color: var(--bg-muted);
    font-weight: 600;
}

.data-table td:first-child, .data-table th:first-child {
    text-align: left;
}

.section-row td {
    background-color: #f8f9fa;
    text-align: center;
}

.highlight-row {
    background-color: #f0f7ff;
}

/* BibTeX */
.bibtex-container {
    background-color: var(--bg-muted);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 20px;
    overflow-x: auto;
}

.bibtex-container pre {
    margin: 0;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
}

.copy-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background-color: var(--bg-main);
    color: var(--text-muted);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 6px 12px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}

.copy-btn:hover {
    background-color: var(--bg-muted);
    color: var(--text-main);
    border-color: var(--text-muted);
}

/* Footer */
footer {
    text-align: center;
    padding: 40px 0;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Navigation Bar */
.navbar {
    position: sticky;
    top: 0;
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 14px 0;
    transition: background-color 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

/* Top Left Brand Logo */
.nav-brand {
    position: absolute;
    left: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text-main);
    font-weight: 700;
    font-size: 1.1rem;
    transition: var(--transition);
}

.nav-brand:hover {
    opacity: 0.85;
}

.nav-logo {
    width: 32px;
    height: 32px;
    border-radius: 6px;
    object-fit: cover;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.nav-brand-text {
    letter-spacing: 0.5px;
}

@media (max-width: 900px) {
    .nav-brand-text {
        display: none;
    }
}

@media (max-width: 600px) {
    .nav-brand {
        position: static;
        margin-right: 8px;
    }
}

.nav-links {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
}

.nav-link {
    color: var(--text-main);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    padding: 8px 16px;
    border-radius: 20px;
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--primary-color);
    background-color: var(--bg-muted);
}

/* Theme Toggle Button */
.theme-toggle {
    position: absolute;
    right: 20px;
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-main);
    width: 36px;
    height: 36px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    flex-shrink: 0;
}
.theme-toggle:hover {
    background-color: var(--bg-muted);
}

/* Dark Mode Variables */
[data-theme="dark"] {
    --primary-color: #58a6ff;
    --primary-hover: #79c0ff;
    --text-main: #c9d1d9;
    --text-muted: #8b949e;
    --bg-main: #0d1117;
    --bg-muted: #161b22;
    --border-color: #30363d;
}

[data-theme="dark"] .navbar {
    background-color: rgba(13, 17, 23, 0.85);
}

[data-theme="dark"] .paper-title {
    color: #f0f6fc;
}

[data-theme="dark"] .audio-card.highlighted {
    background-color: #1f2937;
    border-color: var(--primary-color);
}

[data-theme="dark"] .highlight-row {
    background-color: #1f2937;
}

[data-theme="dark"] .section-row td {
    background-color: #161b22;
}

[data-theme="dark"] .placeholder-box {
    background-color: #21262d;
    border-color: #30363d;
}

[data-theme="dark"] .btn-outline {
    background-color: #161b22;
    border-color: #30363d;
    box-shadow: 0 4px 6px rgba(0,0,0,0.3);
}

[data-theme="dark"] .btn-outline:hover {
    background-color: #21262d;
    border-color: var(--primary-hover);
    color: var(--primary-hover);
    box-shadow: 0 10px 20px rgba(88, 166, 255, 0.15);
}

/* Responsive Media Queries */
@media (max-width: 768px) {
    .hero {
        padding: 50px 0 40px;
    }
    
    .section {
        padding: 40px 0;
    }

    .nav-container {
        justify-content: space-between;
    }

    .theme-toggle {
        position: relative;
        right: auto;
    }

    .nav-links {
        justify-content: flex-start;
        gap: 4px;
    }

    .nav-link {
        padding: 6px 10px;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero {
        padding: 30px 0 20px;
    }

    .section {
        padding: 30px 0;
    }

    .theme-toggle {
        width: 32px;
        height: 32px;
    }
}