* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg:      #ffffff;
    --surface: #f6f8fa;
    --border:  #d1d9e0;
    --text:    #1c2128;
    --muted:   #636e7b;
    --accent:  #0550ae;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

header {
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 0 2rem;
}

nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1100px;
    margin: 0 auto;
    height: 64px;
}

.brand {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text);
    text-decoration: none;
    letter-spacing: -0.02em;
}

nav ul { display: flex; gap: 1.5rem; list-style: none; }
nav a  { text-decoration: none; color: var(--muted); font-size: 0.95rem; }
nav a:hover { color: var(--text); }

.hero {
    max-width: 720px;
    margin: 6rem auto;
    padding: 0 2rem;
    text-align: center;
}

.hero-logo {
    width: 96px;
    height: 96px;
    margin-bottom: 2rem;
}

.hero h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.03em;
}

.content {
    max-width: 720px;
    margin: 6rem auto;
    padding: 0 2rem;
}

.content p {
    font-size: 1.1rem;
    color: var(--muted);
}

.error-page {
    max-width: 600px;
    margin: 8rem auto;
    padding: 0 2rem;
    text-align: center;
}

.error-page h1 { font-size: 6rem; font-weight: 700; color: var(--border); }
.error-page p  { margin: 1rem 0 2rem; color: var(--muted); }
.error-page a  { color: var(--accent); text-decoration: none; }
.error-page a:hover { text-decoration: underline; }

footer {
    text-align: center;
    padding: 2rem;
    color: var(--muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
    margin-top: 4rem;
}

main { min-height: 60vh; }