:root {
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --bg: #f8fafc;
    --text: #1e293b;
    --muted: #64748b;
    --border: #e2e8f0;
    --radius: 10px;
}

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

body {
    font-family: Georgia, 'Times New Roman', serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.75;
    font-size: 17px;
}

.container { max-width: 1080px; margin: 0 auto; padding: 0 24px; }

/* Header */
.site-header {
    background: #fff;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 10;
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}
.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-family: 'Segoe UI', Arial, sans-serif;
    font-weight: 700;
    font-size: 18px;
    color: var(--text);
    text-decoration: none;
}
.main-nav a {
    font-family: 'Segoe UI', Arial, sans-serif;
    font-size: 15px;
    color: var(--muted);
    text-decoration: none;
    margin-left: 22px;
    transition: color .15s;
}
.main-nav a:hover { color: var(--primary); }

/* Hero */
.hero {
    background: linear-gradient(180deg, #eff6ff 0%, var(--bg) 100%);
    padding: 72px 0 48px;
    text-align: center;
}
.hero h1 {
    font-size: 44px;
    line-height: 1.2;
    letter-spacing: -0.5px;
    max-width: 760px;
    margin: 0 auto 18px;
}
.accent { color: var(--primary); }
.lead {
    font-size: 20px;
    color: var(--muted);
    max-width: 680px;
    margin: 0 auto;
}

/* Cards */
.features { padding: 40px 0 24px; }
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
}
.card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 24px;
    transition: box-shadow .2s;
}
.card:hover { box-shadow: 0 8px 24px rgba(37,99,235,.08); }
.card-icon { font-size: 32px; margin-bottom: 14px; }
.card h2 { font-size: 19px; margin-bottom: 10px; line-height: 1.35; }
.card h2 a { color: var(--text); text-decoration: none; }
.card h2 a:hover { color: var(--primary); }
.card p { font-size: 15px; color: var(--muted); margin-bottom: 14px; }
.read-more {
    font-family: 'Segoe UI', Arial, sans-serif;
    font-size: 14px;
    font-weight: 600;
    color: var(--primary);
    text-decoration: none;
}

/* Beginner path */
.beginner-path { padding: 40px 0; }
.beginner-path h2 { font-size: 26px; margin-bottom: 20px; }
.path-list { list-style: none; counter-reset: step; }
.path-list li {
    counter-increment: step;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 20px 16px 64px;
    margin-bottom: 12px;
    position: relative;
    font-size: 16px;
}
.path-list li::before {
    content: counter(step);
    position: absolute;
    left: 22px;
    top: 50%;
    transform: translateY(-50%);
    width: 30px;
    height: 30px;
    background: var(--primary);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'Segoe UI', Arial, sans-serif;
    font-weight: 700;
    font-size: 15px;
}
.path-list a { color: var(--primary); text-decoration: none; font-weight: 600; }
.path-list a:hover { text-decoration: underline; }

/* Notice */
.notice {
    padding: 8px 0 40px;
}
.notice .container {
    background: #fffbeb;
    border: 1px solid #fde68a;
    border-radius: var(--radius);
    padding: 18px 22px;
    font-size: 15px;
    color: #92400e;
}

/* Article layout */
.article {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 48px 56px;
    margin: 40px auto;
    max-width: 800px;
}
.article h1 { font-size: 34px; line-height: 1.25; margin-bottom: 8px; }
.article h2 { font-size: 24px; margin: 36px 0 12px; }
.article h3 { font-size: 19px; margin: 28px 0 10px; }
.article p { margin-bottom: 16px; }
.article ul, .article ol { margin: 0 0 16px 24px; }
.article li { margin-bottom: 8px; }
.article a { color: var(--primary); }
.meta {
    font-family: 'Segoe UI', Arial, sans-serif;
    font-size: 14px;
    color: var(--muted);
    margin-bottom: 28px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}
table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0 24px;
    font-size: 15px;
}
th, td {
    border: 1px solid var(--border);
    padding: 10px 14px;
    text-align: left;
}
th { background: #f1f5f9; font-family: 'Segoe UI', Arial, sans-serif; font-size: 14px; }
.callout {
    background: #eff6ff;
    border-left: 4px solid var(--primary);
    border-radius: 6px;
    padding: 16px 20px;
    margin: 20px 0;
    font-size: 15px;
}

/* Calculator */
.calc-box {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 40px;
    margin: 40px auto;
    max-width: 700px;
}
.calc-box h1 { font-size: 30px; margin-bottom: 10px; }
.calc-box p.sub { color: var(--muted); margin-bottom: 24px; font-size: 16px; }
.calc-row { margin-bottom: 18px; }
.calc-row label {
    display: block;
    font-family: 'Segoe UI', Arial, sans-serif;
    font-weight: 600;
    font-size: 14px;
    margin-bottom: 6px;
}
.calc-row select, .calc-row input {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 16px;
    font-family: 'Segoe UI', Arial, sans-serif;
    background: #fff;
}
.btn-calc {
    display: inline-block;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 8px;
    padding: 12px 28px;
    font-size: 16px;
    font-weight: 600;
    font-family: 'Segoe UI', Arial, sans-serif;
    cursor: pointer;
    margin-top: 8px;
}
.btn-calc:hover { background: var(--primary-dark); }
.calc-result {
    margin-top: 24px;
    padding: 20px 24px;
    background: #f1f5f9;
    border-radius: 8px;
    display: none;
    font-family: 'Segoe UI', Arial, sans-serif;
    font-size: 16px;
}
.calc-result.show { display: block; }
.calc-result .big { font-size: 22px; font-weight: 700; color: var(--primary); }

/* Footer */
.site-footer {
    background: #0f172a;
    color: #94a3b8;
    margin-top: 60px;
    padding: 48px 0 28px;
    font-family: 'Segoe UI', Arial, sans-serif;
    font-size: 14px;
}
.footer-inner { display: flex; gap: 60px; flex-wrap: wrap; }
.footer-col { flex: 1; min-width: 200px; }
.footer-logo { color: #fff; font-weight: 700; font-size: 17px; margin-bottom: 10px; }
.footer-desc { line-height: 1.6; }
.footer-title { color: #fff; font-weight: 600; margin-bottom: 12px; }
.footer-col a {
    display: block;
    color: #94a3b8;
    text-decoration: none;
    margin-bottom: 8px;
}
.footer-col a:hover { color: #fff; }
.copyright {
    margin-top: 36px;
    padding-top: 20px;
    border-top: 1px solid #1e293b;
    font-size: 13px;
    text-align: center;
}

/* Legal pages */
.legal p { margin-bottom: 14px; }
.legal h2 { font-size: 20px; margin: 24px 0 10px; }

/* Responsive tables: scroll inside table, not the page */
.article table {
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

/* Mobile navigation: wrap links, taller header */
@media (max-width: 768px) {
    .site-header { position: static; }
    .header-inner {
        flex-direction: column;
        height: auto;
        padding: 12px 0;
        gap: 8px;
    }
    .main-nav {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 6px 0;
    }
    .main-nav a { margin: 0 10px; font-size: 14px; }
    .hero { padding: 48px 0 32px; }
    .hero h1 { font-size: 30px; }
    .lead { font-size: 18px; }
    .article { padding: 28px 20px; }
    .article h1 { font-size: 26px; }
    .article h2 { font-size: 21px; }
    .calc-box { padding: 24px 20px; }
    .footer-inner { gap: 32px; }
}

/* Phones */
@media (max-width: 480px) {
    .hero { padding: 36px 0 26px; }
    .hero h1 { font-size: 25px; }
    .lead { font-size: 16px; }
    .card { padding: 22px 18px; }
    .article h1 { font-size: 22px; }
    .article h2 { font-size: 19px; }
    .article h3 { font-size: 17px; }
    .calc-box h1 { font-size: 23px; }
    .btn-calc { width: 100%; }
    .path-list li { padding: 14px 16px 14px 58px; }
    .footer-inner { flex-direction: column; gap: 24px; }
}