/* ============================================
   NetSciEd Challenge — Shared Styles
   Aesthetic: Scientific editorial meets network visualization
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:ital,opsz,wght@0,8..60,300;0,8..60,400;0,8..60,600;0,8..60,700;1,8..60,400&family=DM+Sans:ital,opsz,wght@0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,400&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
    --color-bg: #FAFAF8;
    --color-surface: #FFFFFF;
    --color-text: #2C2C2C;
    --color-text-secondary: #5A5A5A;
    --color-text-muted: #8A8A8A;
    --color-primary: #1A7A6D;
    --color-primary-light: #E8F5F2;
    --color-primary-dark: #0F5249;
    --color-accent: #D4548A;
    --color-accent-light: #FDF0F5;
    --color-node-teal: #4CC9B0;
    --color-node-pink: #E87BAF;
    --color-node-yellow: #F2C94C;
    --color-node-purple: #9B72CF;
    --color-border: #E5E5E0;
    --color-border-light: #F0F0EC;
    --font-display: 'Source Serif 4', Georgia, serif;
    --font-body: 'DM Sans', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    --max-width: 1120px;
    --header-height: 72px;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a { color: var(--color-primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--color-primary-dark); }

img { max-width: 100%; height: auto; }

/* ---- Typography ---- */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    color: var(--color-text);
    line-height: 1.2;
    font-weight: 600;
}

h1 { font-size: clamp(2rem, 4vw, 3rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.5rem, 3vw, 2.2rem); letter-spacing: -0.01em; }
h3 { font-size: clamp(1.2rem, 2vw, 1.5rem); }
h4 { font-size: 1.1rem; }

p { margin-bottom: 1em; }
p:last-child { margin-bottom: 0; }

strong { font-weight: 600; }
em { font-style: italic; }

/* ---- Layout ---- */
.container {
    width: 90%;
    max-width: var(--max-width);
    margin: 0 auto;
}

.container--narrow {
    max-width: 780px;
}

/* ---- Header ---- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(250, 250, 248, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
    height: var(--header-height);
}

.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.logo-link {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    flex-shrink: 0;
}

.logo-link img {
    height: 44px;
    width: auto;
    border-radius: 4px;
}

.logo-text {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-text);
    letter-spacing: -0.01em;
}

.logo-text span {
    color: var(--color-primary);
}

.site-nav { display: flex; align-items: center; gap: 6px; }

.site-nav a {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    padding: 8px 14px;
    border-radius: 6px;
    transition: all 0.2s;
    white-space: nowrap;
}

.site-nav a:hover {
    color: var(--color-primary);
    background: var(--color-primary-light);
}

.site-nav a.active {
    color: var(--color-primary);
    background: var(--color-primary-light);
    font-weight: 600;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    color: var(--color-text);
    font-size: 1.5rem;
    line-height: 1;
}

/* ---- Hero Sections ---- */
.hero {
    padding: 80px 0 60px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -200px;
    right: -200px;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(76, 201, 176, 0.08) 0%, transparent 70%);
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -150px;
    left: -150px;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(212, 84, 138, 0.06) 0%, transparent 70%);
    pointer-events: none;
}

.hero h1 {
    margin-bottom: 20px;
}

.hero .subtitle {
    font-size: clamp(1.05rem, 1.5vw, 1.2rem);
    color: var(--color-text-secondary);
    max-width: 640px;
    line-height: 1.6;
}

.hero .badge {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-primary);
    background: var(--color-primary-light);
    padding: 6px 14px;
    border-radius: 100px;
    margin-bottom: 20px;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

/* ---- Content Sections ---- */
.section {
    padding: 60px 0;
}

.section--alt {
    background: var(--color-surface);
    border-top: 1px solid var(--color-border-light);
    border-bottom: 1px solid var(--color-border-light);
}

.section-header {
    margin-bottom: 40px;
}

.section-header h2 {
    margin-bottom: 12px;
}

.section-header p {
    color: var(--color-text-secondary);
    max-width: 600px;
}

/* ---- Cards ---- */
.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 32px;
    transition: box-shadow 0.3s, transform 0.2s;
}

.card:hover {
    box-shadow: 0 8px 30px rgba(0,0,0,0.06);
    transform: translateY(-2px);
}

.card h3 {
    margin-bottom: 10px;
}

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

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

/* ---- Node Dots (decorative) ---- */
.node-dot {
    display: inline-block;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    margin-right: 8px;
    flex-shrink: 0;
}

.node-dot--teal { background: var(--color-node-teal); }
.node-dot--pink { background: var(--color-node-pink); }
.node-dot--yellow { background: var(--color-node-yellow); }
.node-dot--purple { background: var(--color-node-purple); }

/* ---- Buttons ---- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-body);
    font-size: 0.95rem;
    font-weight: 600;
    padding: 12px 28px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

.btn--primary {
    background: var(--color-primary);
    color: #fff;
}

.btn--primary:hover {
    background: var(--color-primary-dark);
    color: #fff;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(26, 122, 109, 0.3);
}

.btn--outline {
    background: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

.btn--outline:hover {
    background: var(--color-primary-light);
    color: var(--color-primary-dark);
}

.btn--small {
    font-size: 0.85rem;
    padding: 8px 18px;
}

/* ---- Form Styles ---- */
.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 8px;
    color: var(--color-text);
}

.form-group .hint {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-top: 4px;
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="url"],
.form-group input[type="number"],
.form-group select,
.form-group textarea {
    width: 100%;
    font-family: var(--font-body);
    font-size: 0.95rem;
    padding: 12px 16px;
    border: 1px solid var(--color-border);
    border-radius: 8px;
    background: var(--color-surface);
    color: var(--color-text);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(26, 122, 109, 0.1);
}

.form-group textarea { resize: vertical; min-height: 120px; }

.form-group .concept-tag {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--color-primary);
    background: var(--color-primary-light);
    padding: 3px 10px;
    border-radius: 100px;
    margin-left: 8px;
    vertical-align: middle;
}

/* ---- Code / Technical blocks ---- */
.code-block {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    background: #1E1E2E;
    color: #CDD6F4;
    padding: 24px;
    border-radius: 10px;
    overflow-x: auto;
    line-height: 1.6;
}

.code-block .keyword { color: var(--color-node-purple); }
.code-block .string { color: var(--color-node-teal); }
.code-block .comment { color: #6C7086; }
.code-block .label { color: var(--color-node-yellow); }
.code-block .relation { color: var(--color-node-pink); }

/* ---- Footer ---- */
.site-footer {
    background: #1A1A1E;
    color: #9A9A9A;
    padding: 48px 0 32px;
    font-size: 0.875rem;
}

.site-footer a { color: #ccc; }
.site-footer a:hover { color: #fff; }

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 40px;
    flex-wrap: wrap;
}

.footer-col h4 {
    color: #fff;
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 14px;
}

.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 8px; }

.footer-bottom {
    margin-top: 40px;
    padding-top: 24px;
    border-top: 1px solid #333;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    font-size: 0.8rem;
    color: #666;
}

/* ---- Utility ---- */
.text-center { text-align: center; }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 32px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }

/* ---- Responsive ---- */
@media (max-width: 768px) {
    .site-nav { 
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--color-surface);
        flex-direction: column;
        padding: 16px;
        border-bottom: 1px solid var(--color-border);
        box-shadow: 0 8px 20px rgba(0,0,0,0.08);
    }
    .site-nav.open { display: flex; }
    .mobile-menu-toggle { display: block; }
    .hero { padding: 50px 0 40px; }
    .section { padding: 40px 0; }
    .card { padding: 24px; }
    .card-grid { grid-template-columns: 1fr; }
    .footer-inner { flex-direction: column; }
}