:root {
    --bg: #0d1117;
    --text: #c9d1d9;
    --sub: #8b949e;
    --border: #30363d;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: system-ui, -apple-system, sans-serif;
    margin: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
}

header {
    text-align: center;
    margin: 3rem auto 2rem;
    width: 90%;
    max-width: 1200px;
}

h1 {
    color: #fff;
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--sub);
    font-size: 1rem;
    margin-bottom: 1rem;
}

.stats-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    width: 90vw;
    max-width: 780px;
    margin: 0 auto 2rem;
}

.stat-card {
    background: #161b22;
    border: 1px solid var(--border);
    padding: 1rem;
    border-radius: 6px;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: #fff;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--sub);
}

@media (max-width: 600px) {
    .stats-container {
        gap: .5rem;
    }
    .stat-card {
        padding: .75rem;
    }
    .stat-value {
        font-size: 1.25rem;
    }
}

.years-container {
    width: 90vw;
    max-width: 780px;
    margin: 0 auto;
    background: var(--bg);
}

.year-section {
    margin-bottom: 20px;
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 20px;
}

.year-header {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    font-weight: 600;
    color: #fff;
}

.graph-wrapper {
    display: flex;
    overflow-x: auto;
}

.main-graph-area {
    display: flex;
    flex-direction: column;
}

.contribution-grid {
    display: grid;
    grid-template-columns: repeat(53, 14px);
    grid-template-rows: repeat(5, 14px);
    grid-auto-flow: row;
}

.day-cell {
    width: 10px;
    height: 10px;
    background: #161b22;
    border-radius: 2px;
    outline: 1px solid rgba(27, 31, 35, 0.06);
    outline-offset: -1px;
}

.day-cell:hover {
    outline: 2px solid rgba(255, 255, 255, 0.5);
    z-index: 2;
    position: relative;
}

.tooltip {
    position: fixed;
    background: #24292f;
    color: #fff;
    padding: 5px 10px;
    border-radius: 6px;
    font-size: 11px;
    pointer-events: none;
    z-index: 9999;
    display: none;
}

.level-0 { background: #161b22; }
.level-4 { background: #39d353; }