:root {
    --bg: #f4f5f7;
    --panel: #ffffff;
    --text: #20242a;
    --muted: #68707b;
    --line: #dde1e6;
    --accent: #315f8c;
    --accent-soft: #e8f0f7;
    --max: 980px;
}

* {
    box-sizing: border-box;
}

html {
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,
                 "Segoe UI", sans-serif;
    background: var(--bg);
    color: var(--text);
}

body {
    margin: 0;
    line-height: 1.65;
}

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

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

.nav {
    max-width: var(--max);
    margin: 0 auto;
    padding: 20px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 24px;
}

.brand {
    font-weight: 700;
    color: var(--text);
    letter-spacing: .02em;
}

nav {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
}

nav a {
    color: var(--muted);
    font-size: .95rem;
}

main {
    max-width: var(--max);
    margin: 0 auto;
    padding: 64px 24px;
}

.hero {
    padding: 24px 0 48px;
}

.hero h1 {
    margin: 0 0 18px;
    max-width: 780px;
    font-size: clamp(2.2rem, 6vw, 4.4rem);
    line-height: 1.04;
    letter-spacing: -.04em;
}

.hero p {
    max-width: 680px;
    color: var(--muted);
    font-size: 1.15rem;
}

.section-title {
    margin-top: 54px;
    margin-bottom: 18px;
    font-size: 1.45rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 18px;
}

.card {
    background: var(--panel);
    border: 1px solid var(--line);
    border-radius: 14px;
    padding: 24px;
}

.card h2,
.card h3 {
    margin-top: 0;
}

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

.meta {
    color: var(--muted);
    font-size: .88rem;
    margin-bottom: 8px;
}

.tag {
    display: inline-block;
    padding: 4px 9px;
    margin-right: 5px;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent);
    font-size: .78rem;
}

article {
    max-width: 760px;
}

article h1 {
    font-size: 2.4rem;
    line-height: 1.15;
}

article h2 {
    margin-top: 36px;
}

footer {
    max-width: var(--max);
    margin: 0 auto;
    padding: 28px 24px 46px;
    color: var(--muted);
    border-top: 1px solid var(--line);
    font-size: .9rem;
}

.error-page {
    min-height: 55vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.error-code {
    font-size: 5rem;
    font-weight: 700;
    margin: 0;
    line-height: 1;
}

@media (max-width: 620px) {
    .nav {
        align-items: flex-start;
        flex-direction: column;
    }

    main {
        padding-top: 38px;
    }
}