:root {
    --text: #1f2937;
    --muted: #6b7280;
    --line: #e5e7eb;
    --accent: #1d4ed8;
    --bg: #ffffff;
    --soft: #f8fafc;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.65;
}

.container {
    width: min(960px, calc(100% - 40px));
    margin: 0 auto;
}

header {
    border-bottom: 1px solid var(--line);
    background: #fff;
}

.navbar {
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.site-name {
    font-size: 1.15rem;
    font-weight: 700;
    text-decoration: none;
    color: var(--text);
}

nav {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
}

nav a {
    color: var(--muted);
    text-decoration: none;
    font-size: 0.95rem;
}

nav a:hover,
nav a.active {
    color: var(--accent);
}

main {
    padding: 64px 0 80px;
}

.hero {
    max-width: 760px;
    padding: 24px 0 40px;
}

h1 {
    font-size: clamp(2.2rem, 6vw, 4rem);
    line-height: 1.05;
    margin: 0 0 20px;
    letter-spacing: -0.03em;
}

h2 {
    margin-top: 48px;
    font-size: 1.6rem;
}

h3 {
    margin-bottom: 6px;
}

.subtitle {
    font-size: 1.25rem;
    color: var(--muted);
    margin-bottom: 24px;
}

.lead {
    font-size: 1.08rem;
    max-width: 720px;
}

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 18px;
    margin-top: 24px;
}

.card {
    border: 1px solid var(--line);
    border-radius: 10px;
    padding: 22px;
    background: var(--soft);
}

.card p {
    margin-bottom: 0;
    color: var(--muted);
}

.section-list {
    padding-left: 20px;
}

a {
    color: var(--accent);
}

footer {
    border-top: 1px solid var(--line);
    color: var(--muted);
    font-size: 0.9rem;
    padding: 24px 0;
}

@media (max-width: 680px) {
    .navbar {
        align-items: flex-start;
        flex-direction: column;
        padding: 18px 0;
    }

    nav {
        gap: 14px;
    }

    main {
        padding-top: 40px;
    }
}