/* ========================================
   SAEMark Project Page Styles
   ======================================== */

/* CSS Variables */
:root {
    /* Colors - Deep academic blue with warm accents */
    --color-primary: #1a365d;
    --color-primary-light: #2c5282;
    --color-primary-dark: #0d1b2a;
    --color-accent: #c53030;
    --color-accent-light: #e53e3e;
    
    /* Neutrals */
    --color-bg: #fafafa;
    --color-bg-alt: #f0f4f8;
    --color-bg-dark: #1a202c;
    --color-text: #1a202c;
    --color-text-muted: #4a5568;
    --color-text-light: #718096;
    --color-border: #e2e8f0;
    
    /* Typography */
    --font-heading: 'Crimson Pro', Georgia, serif;
    --font-body: 'Source Sans 3', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    
    /* 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 -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);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
}

/* Container */
.container {
    width: 100%;
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-primary-dark);
}

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

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

strong {
    font-weight: 600;
}

em {
    font-style: italic;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    position: relative;
    padding: var(--space-4xl) 0;
    text-align: center;
    overflow: hidden;
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 50%, var(--color-primary-light) 100%);
    color: #fff;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background-image: 
        radial-gradient(ellipse at 20% 80%, rgba(255, 255, 255, 0.03) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(255, 255, 255, 0.05) 0%, transparent 50%),
        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' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.02'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    pointer-events: none;
}

.venue-badge {
    display: inline-block;
    margin-bottom: var(--space-xl);
}

.venue-badge span {
    display: inline-block;
    padding: var(--space-sm) var(--space-lg);
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 9999px;
    backdrop-filter: blur(4px);
}

.title {
    font-size: clamp(1.75rem, 4vw, 2.75rem);
    font-weight: 700;
    max-width: 900px;
    margin: 0 auto var(--space-2xl);
    color: #fff;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.title .highlight {
    color: #fbd38d;
    font-weight: 700;
}

/* Authors */
.authors {
    margin-bottom: var(--space-2xl);
}

.author-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-sm) var(--space-lg);
    margin-bottom: var(--space-md);
}

.author {
    font-size: 1.1rem;
    font-weight: 500;
}

.author a {
    color: rgba(255, 255, 255, 0.95);
    border-bottom: 1px solid transparent;
    transition: border-color var(--transition-fast);
}

.author a:hover {
    color: #fff;
    border-bottom-color: rgba(255, 255, 255, 0.5);
}

.author sup {
    font-size: 0.7em;
    margin-left: 1px;
    color: #fbd38d;
}

.affiliations {
    margin-bottom: var(--space-sm);
}

.affiliation {
    font-size: 1rem;
    font-weight: 500;
    color: rgba(255, 255, 255, 0.9);
}

.author-notes {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.7);
}

/* Hero Buttons */
.hero-buttons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-md);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    cursor: pointer;
    border: 2px solid transparent;
}

.btn .icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.btn-primary {
    background: #fff;
    color: var(--color-primary-dark);
    border-color: #fff;
    box-shadow: var(--shadow-lg);
}

.btn-primary:hover {
    background: #fbd38d;
    border-color: #fbd38d;
    color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.btn-secondary {
    background: transparent;
    color: #fff;
    border-color: rgba(255, 255, 255, 0.4);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.6);
    color: #fff;
    transform: translateY(-2px);
}

/* ========================================
   Sections
   ======================================== */
.section {
    padding: var(--space-4xl) 0;
}

.section-title {
    font-size: 1.75rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--space-2xl);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    margin: var(--space-md) auto 0;
    border-radius: 2px;
}

/* Abstract Section */
.abstract-section {
    background: var(--color-bg);
}

.abstract-content {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--color-text);
}

.abstract-content p {
    margin-bottom: var(--space-lg);
    text-align: justify;
}

.abstract-content p:last-child {
    margin-bottom: 0;
}

.abstract-content strong {
    color: var(--color-primary-dark);
}

.abstract-content em {
    color: var(--color-primary);
}

/* Key Idea Section */
.key-idea-section {
    background: var(--color-bg-alt);
}

.key-idea-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-xl);
}

.idea-card {
    background: #fff;
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.idea-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.idea-icon {
    width: 48px;
    height: 48px;
    margin-bottom: var(--space-lg);
    color: var(--color-primary);
}

.idea-icon svg {
    width: 100%;
    height: 100%;
}

.idea-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-md);
    color: var(--color-primary-dark);
}

.idea-card p {
    color: var(--color-text-muted);
    font-size: 0.95rem;
}

.idea-card em {
    font-style: normal;
    color: var(--color-primary);
    font-weight: 500;
}

/* How Section */
.how-section {
    background: #fff;
}

.how-content {
    max-width: 700px;
    margin: 0 auto;
}

.how-steps {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    margin-bottom: var(--space-2xl);
}

.step {
    display: flex;
    gap: var(--space-lg);
    align-items: flex-start;
}

.step-number {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
    color: #fff;
    font-weight: 700;
    font-size: 1.125rem;
    border-radius: 50%;
    box-shadow: var(--shadow-md);
}

.step-content h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--space-xs);
    color: var(--color-primary-dark);
}

.step-content p {
    color: var(--color-text-muted);
    font-size: 0.95rem;
}

.guarantee-box {
    background: linear-gradient(135deg, var(--color-bg-alt), #fff);
    border-left: 4px solid var(--color-accent);
    padding: var(--space-lg);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.guarantee-box h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-accent);
}

.guarantee-box p {
    color: var(--color-text);
    font-size: 0.95rem;
    font-family: var(--font-body);
}

.guarantee-box sub {
    font-size: 0.75em;
}

.guarantee-box sup {
    font-size: 0.75em;
}

/* Citation Section */
.citation-section {
    background: var(--color-bg-alt);
}

.citation-intro {
    text-align: center;
    color: var(--color-text-muted);
    margin-bottom: var(--space-xl);
    font-size: 1.1rem;
}

.citation-box {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
    background: var(--color-bg-dark);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.citation-box pre {
    padding: var(--space-xl);
    overflow-x: auto;
}

.citation-box code {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    line-height: 1.6;
    color: #e2e8f0;
    white-space: pre;
}

.copy-btn {
    position: absolute;
    top: var(--space-md);
    right: var(--space-md);
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-sm);
    color: #e2e8f0;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.copy-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.3);
}

.copy-btn svg {
    width: 18px;
    height: 18px;
}

.copy-btn.copied {
    background: #38a169;
    border-color: #38a169;
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--color-primary-dark);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--space-2xl) 0;
}

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

.footer-venue {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: var(--space-xs);
    color: #fff;
}

.footer-location {
    font-size: 0.9rem;
    margin-bottom: var(--space-lg);
    color: rgba(255, 255, 255, 0.7);
}

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

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: #fbd38d;
}

.footer-links .divider {
    color: rgba(255, 255, 255, 0.3);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    :root {
        --space-4xl: 4rem;
        --space-3xl: 3rem;
        --space-2xl: 2rem;
    }
    
    .hero {
        padding: var(--space-3xl) 0;
    }
    
    .title {
        font-size: 1.5rem;
    }
    
    .author-list {
        gap: var(--space-xs) var(--space-md);
    }
    
    .author {
        font-size: 0.95rem;
    }
    
    .author-notes {
        flex-direction: column;
        gap: var(--space-xs);
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        max-width: 280px;
        justify-content: center;
    }
    
    .abstract-content {
        font-size: 1rem;
    }
    
    .abstract-content p {
        text-align: left;
    }
    
    .key-idea-grid {
        grid-template-columns: 1fr;
    }
    
    .step {
        gap: var(--space-md);
    }
    
    .step-number {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }
    
    .citation-box pre {
        padding: var(--space-lg);
        font-size: 0.75rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-md);
    }
    
    .section {
        padding: var(--space-3xl) 0;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
}

/* ========================================
   Animations
   ======================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero .venue-badge,
.hero .title,
.hero .authors,
.hero .hero-buttons {
    animation: fadeInUp 0.6s ease-out backwards;
}

.hero .venue-badge { animation-delay: 0.1s; }
.hero .title { animation-delay: 0.2s; }
.hero .authors { animation-delay: 0.3s; }
.hero .hero-buttons { animation-delay: 0.4s; }

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* Focus states */
a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}