:root {
    --fg: #111;
    --bg: #fff;
    --muted: #666;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --card-bg: #ffffff;
    --card-border: #e5e7eb;
}
@media (prefers-color-scheme: dark) {
    :root {
        --fg: #e5e7eb;
        --bg: #0b0f14;
        --muted: #9ca3af;
        --accent: #60a5fa;
        --accent-hover: #3b82f6;
        --card-bg: #1a1f28;
        --card-border: #374151;
    }
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html,
body {
    height: 100%;
}
body {
    font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu,
        "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    color: var(--fg);
    background: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
}
.container {
    max-width: 800px;
    width: 100%;
}
header {
    text-align: center;
    margin-bottom: 48px;
}
h1 {
    font-size: clamp(28px, 5vw, 42px);
    margin-bottom: 12px;
}
.subtitle {
    color: var(--muted);
    font-size: clamp(14px, 2vw, 16px);
}
.practice-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-bottom: 32px;
}
.practice-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 32px 24px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
    text-decoration: none;
    display: block;
}
.practice-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(37, 99, 235, 0.15);
    border-color: var(--accent);
}
.practice-card:active {
    transform: translateY(-2px);
}
.card-icon {
    font-size: 48px;
    margin-bottom: 16px;
    display: block;
}
.card-title {
    font-size: 24px;
    font-weight: 600;
    color: var(--fg);
    margin-bottom: 8px;
}
.card-description {
    color: var(--muted);
    font-size: 14px;
    line-height: 1.5;
}
footer {
    text-align: center;
    color: var(--muted);
    font-size: 14px;
    padding-top: 24px;
    border-top: 1px solid var(--card-border);
}
@media (max-width: 640px) {
    .practice-grid {
        grid-template-columns: 1fr;
    }
}