:root {
    color-scheme: light dark;
    --bg: #ffffff;
    --fg: #1a1a1a;
    --muted: #5a5a5a;
    --border: #e0e0e0;
    --accent: #3f51b5;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #121212;
        --fg: #f0f0f0;
        --muted: #a0a0a0;
        --border: #333333;
        --accent: #8c9eff;
    }
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family:
        system-ui,
        -apple-system,
        Segoe UI,
        Roboto,
        sans-serif;
    background: var(--bg);
    color: var(--fg);
    line-height: 1.6;
}

header {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem 1rem 0;
}

header img.logo {
    max-width: 320px;
    width: 80%;
    height: auto;
}

nav.tabs {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
    border-bottom: 1px solid var(--border);
    width: 100%;
    max-width: 640px;
    justify-content: center;
}

nav.tabs a {
    display: inline-block;
    padding: 0.75rem 1.25rem;
    text-decoration: none;
    color: var(--muted);
    border-bottom: 3px solid transparent;
    font-weight: 500;
}

nav.tabs a:hover {
    color: var(--fg);
}

nav.tabs a.active,
nav.tabs a[aria-current='page'] {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

main {
    max-width: 720px;
    margin: 0 auto;
    padding: 2rem 1.5rem 4rem;
}

main h1 {
    font-size: 1.75rem;
}

main h2 {
    font-size: 1.25rem;
    margin-top: 2.5rem;
}

main section + section {
    margin-top: 2rem;
}

.todo {
    color: #b45309;
    font-weight: 600;
}

@media (prefers-color-scheme: dark) {
    .todo {
        color: #fbbf24;
    }
}

ul.goals li {
    margin-bottom: 0.5rem;
}

p.warning {
    padding: 0.75rem 1rem;
    border-left: 3px solid var(--accent);
    background: color-mix(in srgb, var(--accent) 10%, transparent);
    color: var(--muted);
}