:root {
    --bg: #0d1117;
    --surface: #161b22;
    --surface-2: #1c232c;
    --border: #30363d;
    --text: #e6edf3;
    --text-dim: #8b949e;
    --accent: #ff8b3d;
    --accent-dim: #c45c1f;
    --link: #58a6ff;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "Hiragino Sans",
        "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
    text-decoration: underline;
}

header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 16px 0;
    position: sticky;
    top: 0;
    z-index: 10;
}

header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

header .logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 700;
    font-size: 18px;
    color: var(--text);
}

header .logo img {
    width: 32px;
    height: 32px;
    border-radius: 8px;
}

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

header nav a {
    color: var(--text-dim);
    font-size: 14px;
}

header nav a:hover {
    color: var(--text);
    text-decoration: none;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 24px;
}

.hero {
    padding: 80px 0 60px;
    text-align: center;
}

.hero img.app-icon {
    width: 120px;
    height: 120px;
    border-radius: 24px;
    margin-bottom: 24px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.hero h1 {
    font-size: 40px;
    margin-bottom: 12px;
    letter-spacing: -0.02em;
}

.hero .tagline {
    font-size: 18px;
    color: var(--text-dim);
    margin-bottom: 32px;
}

.cta {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--accent);
    color: #1a0e00;
    padding: 12px 28px;
    border-radius: 10px;
    font-weight: 600;
    font-size: 16px;
    transition: background 0.15s;
}

.cta:hover {
    background: var(--accent-dim);
    color: #fff;
    text-decoration: none;
}

.cta.secondary {
    background: var(--surface-2);
    color: var(--text);
    border: 1px solid var(--border);
    margin-left: 12px;
}

.cta.secondary:hover {
    background: var(--surface);
    color: var(--text);
}

section {
    padding: 56px 0;
    border-top: 1px solid var(--border);
}

section h2 {
    font-size: 28px;
    margin-bottom: 24px;
    letter-spacing: -0.01em;
}

section h3 {
    font-size: 18px;
    margin: 24px 0 12px;
    color: var(--text);
}

section p {
    margin-bottom: 16px;
    color: var(--text-dim);
}

section ul, section ol {
    margin: 0 0 16px 24px;
    color: var(--text-dim);
}

section li {
    margin-bottom: 8px;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-top: 32px;
}

.feature {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
}

.feature h3 {
    margin-top: 0;
    color: var(--accent);
}

.feature p {
    margin-bottom: 0;
    font-size: 14px;
}

.legal-doc {
    max-width: 760px;
    margin: 0 auto;
    padding: 56px 24px;
}

.legal-doc h1 {
    font-size: 32px;
    margin-bottom: 8px;
}

.legal-doc .updated {
    color: var(--text-dim);
    font-size: 14px;
    margin-bottom: 32px;
}

.legal-doc h2 {
    font-size: 20px;
    margin: 32px 0 12px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 8px;
}

.legal-doc h3 {
    font-size: 16px;
    margin: 20px 0 8px;
}

.legal-doc p, .legal-doc li {
    color: var(--text);
}

.support-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
    margin: 24px 0;
}

.support-card .email {
    font-family: ui-monospace, "SF Mono", Menlo, monospace;
    color: var(--accent);
    font-size: 18px;
}

footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 40px 0;
    text-align: center;
    color: var(--text-dim);
    font-size: 14px;
}

footer .container {
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: center;
}

footer nav {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    justify-content: center;
}

footer nav a {
    color: var(--text-dim);
}

@media (max-width: 600px) {
    .hero {
        padding: 56px 0 40px;
    }

    .hero h1 {
        font-size: 28px;
    }

    .hero .tagline {
        font-size: 16px;
    }

    section {
        padding: 40px 0;
    }

    section h2 {
        font-size: 22px;
    }

    .cta.secondary {
        margin-left: 0;
        margin-top: 12px;
    }
}