:root {
    --bg: #f4f4f9;
    --container-bg: #ffffff;
    --text: #333333;
    --text-muted: #666666;
    --accent: #007bff;
    --accent-light: rgba(0, 123, 255, 0.1);
    --nav-bg: #ffffff;
    --nav-border: #e0e0e0;
    --card-bg: rgba(0, 123, 255, 0.08);
    --record-hot: rgba(255, 80, 50, 0.12);
    --record-cold: rgba(0, 150, 255, 0.12);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #121212;
        --container-bg: #1e1e1e;
        --text: #e0e0e0;
        --text-muted: #999999;
        --accent: #4da6ff;
        --accent-light: rgba(77, 166, 255, 0.12);
        --nav-bg: #1a1a1a;
        --nav-border: #333333;
        --card-bg: rgba(77, 166, 255, 0.1);
        --record-hot: rgba(255, 100, 70, 0.15);
        --record-cold: rgba(77, 166, 255, 0.15);
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    margin: 0;
    padding: 0;
}

/* Navigation */
.nav {
    background: var(--nav-bg);
    border-bottom: 1px solid var(--nav-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-inner {
    max-width: 1000px;
    margin: auto;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0;
    padding: 0 1rem;
}

.nav-brand {
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--accent);
    padding: 0.85rem 1rem 0.85rem 0;
    text-decoration: none;
    white-space: nowrap;
    margin-right: 0.5rem;
}

.nav-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0;
    margin: 0;
    padding: 0;
    list-style: none;
}

.nav-links a {
    display: block;
    padding: 0.85rem 0.85rem;
    text-decoration: none;
    color: var(--text-muted);
    font-size: 0.9rem;
    border-bottom: 3px solid transparent;
    transition: color 0.15s, border-color 0.15s;
    white-space: nowrap;
}

.nav-links a:hover { color: var(--text); }
.nav-links a.active {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

/* Main container */
.container {
    max-width: 1000px;
    margin: auto;
    background: var(--container-bg);
    padding: 1.5rem 1rem;
    min-height: calc(100vh - 50px);
}

h1 { font-size: 1.5rem; margin: 0 0 0.25rem 0; }
h2 { font-size: 1.2rem; margin: 1.5rem 0 0.75rem 0; }
h3 { font-size: 1rem; margin: 1rem 0 0.5rem 0; color: var(--text-muted); font-weight: 600; }

.subtitle {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin: 0 0 1.5rem 0;
}

/* Stats grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 0.6rem;
    margin-bottom: 1.5rem;
}

.stat-card {
    background: var(--card-bg);
    padding: 0.9rem 0.75rem;
    border-radius: 8px;
    text-align: center;
}

.stat-card .year {
    font-size: 0.75rem;
    color: var(--text-muted);
    display: block;
    margin-bottom: 0.2rem;
}

.stat-card .value {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--accent);
    display: block;
}

/* Records grid */
.records-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.record-card {
    border-radius: 8px;
    padding: 1rem;
    text-align: center;
}

.record-card.hot { background: var(--record-hot); }
.record-card.cold { background: var(--record-cold); }

.record-card .label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    display: block;
    margin-bottom: 0.3rem;
}

.record-card .record-value {
    font-size: 1.8rem;
    font-weight: 700;
    display: block;
    line-height: 1;
}

.record-card.hot .record-value { color: #e05030; }
.record-card.cold .record-value { color: var(--accent); }

.record-card .record-date {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.3rem;
    display: block;
}

/* Charts */
.chart {
    width: 100%;
    height: clamp(300px, 50vh, 500px);
    margin-top: 0.5rem;
    margin-bottom: 1rem;
}

.chart-tall {
    width: 100%;
    height: clamp(400px, 60vh, 600px);
    margin-top: 0.5rem;
    margin-bottom: 1rem;
}

/* Controls */
.controls {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
    padding: 0.75rem;
    background: var(--card-bg);
    border-radius: 8px;
}

.controls label {
    font-size: 0.85rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 0.35rem;
    cursor: pointer;
}

.controls select {
    background: var(--container-bg);
    color: var(--text);
    border: 1px solid var(--nav-border);
    border-radius: 4px;
    padding: 0.3rem 0.5rem;
    font-size: 0.85rem;
}

.year-checkboxes {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-bottom: 1rem;
}

.year-check-label {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    background: var(--card-bg);
    border-radius: 4px;
    padding: 0.3rem 0.55rem;
    font-size: 0.8rem;
    cursor: pointer;
    user-select: none;
}

.tip {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
    margin: 0.5rem 0;
}

.loading {
    color: var(--text-muted);
    font-style: italic;
    padding: 2rem 0;
    text-align: center;
}

/* Footer */
.footer {
    max-width: 1000px;
    margin: 0 auto;
    padding: 1rem;
    font-size: 0.8rem;
    color: var(--text-muted);
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem 1.5rem;
    border-top: 1px solid var(--nav-border);
    margin-top: 2rem;
}

.footer a { color: var(--text-muted); text-decoration: none; }
.footer a:hover { color: var(--accent); }

@media (max-width: 480px) {
    .container { padding: 1rem 0.75rem; }
    h1 { font-size: 1.25rem; }
    .nav-brand { font-size: 0.85rem; }
    .nav-links a { padding: 0.7rem 0.6rem; font-size: 0.8rem; }
}