:root {
    --color-primary: #00bcd4;
    --color-primary-dark: #0097a7;
    --color-primary-light: #e0f7fa;
    --color-accent: #40e0d0;
    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-light: #94a3b8;
    --color-bg: #ffffff;
    --color-bg-secondary: #f8fafc;
    --color-bg-card: #ffffff;
    --color-border: #e2e8f0;
    --color-border-light: #f1f5f9;
    --color-upgrade: #8b5cf6;
    --color-feature: #10b981;
    --color-fix: #f59e0b;
    --color-breaking: #ef4444;
    --color-timeline: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.1);
}

body.dark-mode {
    --color-text: #e2e8f0;
    --color-text-secondary: #94a3b8;
    --color-text-light: #64748b;
    --color-bg: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-bg-card: #1e293b;
    --color-border: #334155;
    --color-border-light: #1e293b;
    --color-primary-light: rgba(0,188,212,0.12);
    --color-timeline: #334155;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.2);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.4);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.7;
    transition: background 0.3s ease, color 0.3s ease;
}

/* Header */
.header {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: #fff;
    padding: 48px 24px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(ellipse at 30% 50%, rgba(0,188,212,0.12) 0%, transparent 60%),
                radial-gradient(ellipse at 70% 50%, rgba(64,224,208,0.08) 0%, transparent 60%);
    pointer-events: none;
}

.header-content {
    position: relative;
    max-width: 700px;
    margin: 0 auto;
}

.header-logo {
    width: 140px;
    margin-bottom: 20px;
    filter: brightness(0) invert(1);
}

.header h1 {
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: 8px;
}

.header h1 span {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header p {
    color: #94a3b8;
    font-size: 0.95rem;
}

.header-links {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-top: 20px;
}

.header-links a {
    color: #cbd5e1;
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    padding: 6px 16px;
    border: 1px solid #334155;
    border-radius: 20px;
    transition: all 0.2s ease;
}

.header-links a:hover {
    background: rgba(0,188,212,0.15);
    border-color: var(--color-primary);
    color: var(--color-primary);
}

/* Dark Mode Toggle */
.dark-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 1px solid var(--color-border);
    background: var(--color-bg-card);
    color: var(--color-text-secondary);
    cursor: pointer;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    box-shadow: var(--shadow-md);
    transition: all 0.2s ease;
}

.dark-toggle:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

body.dark-mode .dark-toggle {
    background: #334155;
    border-color: #475569;
    color: #fbbf24;
}

/* Version Sidebar */
.page-wrapper {
    display: flex;
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 24px;
    gap: 40px;
}

.version-nav {
    position: sticky;
    top: 24px;
    width: 180px;
    flex-shrink: 0;
    align-self: flex-start;
    max-height: calc(100vh - 48px);
    overflow-y: auto;
}

.version-nav-title {
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-light);
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--color-primary);
}

.version-nav a {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 6px 12px;
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    text-decoration: none;
    border-radius: 6px;
    border-left: 2px solid transparent;
    transition: all 0.15s ease;
    margin-bottom: 2px;
}

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

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

.version-nav .nav-date {
    font-size: 0.68rem;
    color: var(--color-text-light);
}

.version-nav .nav-latest {
    font-size: 0.6rem;
    font-weight: 700;
    text-transform: uppercase;
    background: var(--color-primary);
    color: #fff;
    padding: 1px 6px;
    border-radius: 3px;
    letter-spacing: 0.3px;
}

/* Timeline */
.timeline {
    flex: 1;
    min-width: 0;
}

.release {
    position: relative;
    padding-left: 32px;
    padding-bottom: 48px;
    border-left: 2px solid var(--color-timeline);
}

.release:last-child {
    border-left-color: transparent;
    padding-bottom: 0;
}

.release-dot {
    position: absolute;
    left: -7px;
    top: 4px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--color-primary);
    border: 3px solid var(--color-bg);
    box-shadow: 0 0 0 2px var(--color-primary);
    transition: background 0.3s, border-color 0.3s;
}

.release:first-child .release-dot {
    width: 16px;
    height: 16px;
    left: -9px;
    top: 2px;
    border-width: 3px;
    box-shadow: 0 0 0 2px var(--color-primary), 0 0 12px rgba(0,188,212,0.4);
}

.release-header {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 16px;
}

.release-version {
    font-size: 1.4rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--color-text);
}

.release-date {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--color-text-light);
    background: var(--color-bg-secondary);
    padding: 3px 12px;
    border-radius: 20px;
    border: 1px solid var(--color-border);
}

.release-tag {
    font-size: 0.65rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 3px 10px;
    border-radius: 20px;
    color: #fff;
}

.release-tag.latest {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
}

.release-tag.major {
    background: var(--color-upgrade);
}

/* Change Groups */
.change-group {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 10px;
    padding: 20px 24px;
    margin-bottom: 12px;
    box-shadow: var(--shadow-sm);
    transition: background 0.3s, border-color 0.3s, box-shadow 0.3s;
}

.change-group:hover {
    box-shadow: var(--shadow-md);
}

.change-group-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--color-border-light);
}

.change-badge {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 4px 12px;
    border-radius: 6px;
    color: #fff;
}

.change-badge.upgrade {
    background: var(--color-upgrade);
}

.change-badge.feature {
    background: var(--color-feature);
}

.change-badge.fix {
    background: var(--color-fix);
    color: #1e293b;
}

.change-badge-icon {
    font-size: 11px;
}

.change-count {
    font-size: 0.75rem;
    color: var(--color-text-light);
    font-weight: 500;
}

.change-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.change-list li {
    position: relative;
    padding: 5px 0 5px 20px;
    font-size: 0.88rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
}

.change-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 13px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
}

.change-group.type-upgrade .change-list li::before { background: var(--color-upgrade); }
.change-group.type-feature .change-list li::before { background: var(--color-feature); }
.change-group.type-fix .change-list li::before { background: var(--color-fix); }

.change-list li + li {
    border-top: 1px solid var(--color-border-light);
}

/* First release highlight */
.release-initial {
    text-align: center;
    padding: 24px;
    background: linear-gradient(135deg, var(--color-primary-light), transparent);
    border-radius: 10px;
    border: 1px solid var(--color-border);
}

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

/* Footer */
.changelog-footer {
    text-align: center;
    padding: 40px 24px;
    border-top: 1px solid var(--color-border);
    margin-top: 40px;
}

.changelog-footer p {
    font-size: 0.85rem;
    color: var(--color-text-light);
}

.changelog-footer a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
}

.changelog-footer a:hover {
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    .version-nav { display: none; }
    .page-wrapper { padding: 24px 16px; }
    .header { padding: 32px 16px; }
    .header h1 { font-size: 1.5rem; }
    .release-version { font-size: 1.2rem; }
    .change-group { padding: 16px; }
    .header-links { flex-wrap: wrap; }
}

@media print {
    .dark-toggle, .version-nav, .header-links { display: none; }
    .release { break-inside: avoid; }
}