:root {
    --bg: #f7f9fc;
    --surface: #ffffff;
    --surface-strong: #eef2ff;
    --text: #0f172a;
    --muted: #475569;
    --accent: #2563eb;
    --accent-deep: #1d4ed8;
    --line: rgba(148, 163, 184, 0.35);
    --focus: #2563eb;
    --shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
    --shadow-soft: 0 10px 22px rgba(15, 23, 42, 0.08);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Noto Sans SC", "Microsoft YaHei", sans-serif;
    color: var(--text);
    background:
        radial-gradient(900px 520px at 92% -12%, rgba(59, 130, 246, 0.22) 0%, transparent 62%),
        radial-gradient(720px 420px at -12% 22%, rgba(14, 165, 233, 0.18) 0%, transparent 64%),
        var(--bg);
    line-height: 1.6;
}

a {
    color: inherit;
    text-decoration: none;
}

.btn-primary:focus-visible,
.btn-link:focus-visible,
.footer-links a:focus-visible {
    outline: 3px solid var(--focus);
    outline-offset: 2px;
    border-radius: 8px;
}

.hero,
.section,
.footer-inner {
    width: min(1100px, 92vw);
    margin: 0 auto;
}

.hero {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    padding: 64px 0 22px;
    align-items: center;
}

.hero-content h1 {
    margin: 14px 0 10px;
    font-size: clamp(2rem, 9vw, 3.1rem);
    letter-spacing: 0.01em;
    line-height: 1.16;
    max-width: 15ch;
}

.hero-badge {
    display: inline-block;
    padding: 7px 13px;
    border-radius: 999px;
    background: rgba(14, 165, 233, 0.12);
    color: #075985;
    font-size: 12px;
    font-weight: 700;
}

.hero-subtitle {
    margin: 0;
    color: var(--muted);
    max-width: 42ch;
}

.hero-meta {
    margin: 12px 0 0;
    color: var(--muted);
    font-size: 14px;
    font-weight: 600;
}

.hero-actions {
    margin-top: 20px;
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
}

.btn-primary,
.btn-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 46px;
    font-size: 15px;
    font-weight: 700;
}

.btn-primary {
    border-radius: 999px;
    padding: 14px 28px;
    background: linear-gradient(135deg, var(--accent), var(--accent-deep));
    color: #fff;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 22px 34px rgba(37, 99, 235, 0.26);
    filter: saturate(1.05);
}

.btn-link {
    padding: 10px 2px;
    color: #1d4ed8;
    border-bottom: 1px solid transparent;
    transition: color 0.18s ease, border-color 0.18s ease;
}

.btn-link:hover {
    color: #1e40af;
    border-color: currentColor;
}

.hero-brand {
    justify-self: center;
}

.hero-brand img {
    width: min(260px, 64vw);
    height: auto;
    border-radius: 30px;
    box-shadow: var(--shadow-soft);
    background: #fff;
}

.section {
    padding: 30px 0;
}

.section h2 {
    margin: 0 0 12px;
    font-size: clamp(1.4rem, 4vw, 2rem);
    line-height: 1.28;
}

.section-problem {
    color: var(--muted);
    max-width: 72ch;
}

.section-modules {
    padding-top: 36px;
}

.module-card {
    margin-top: 18px;
    border-radius: 22px;
    background: var(--surface);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-soft);
    padding: 18px 18px 20px;
}

.module-header {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 14px;
    align-items: start;
    margin-bottom: 14px;
}

.module-order {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--surface-strong);
    color: var(--accent-deep);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
}

.module-header h3 {
    margin: 0;
    font-size: 1.18rem;
    line-height: 1.35;
}

.module-header p {
    margin: 8px 0 0;
    color: var(--muted);
    max-width: 68ch;
}

.pages-grid {
    display: grid;
    gap: 14px;
}

.page-card {
    border-radius: 16px;
    border: 1px solid var(--line);
    background: var(--surface);
    padding: 12px;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.page-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 14px 26px rgba(15, 23, 42, 0.12);
}

.page-card img {
    width: 100%;
    border-radius: 12px;
    display: block;
    height: auto;
    max-height: 520px;
    object-fit: contain;
    background: #f1f5f9;
}

.page-card h4 {
    margin: 10px 0 6px;
    font-size: 1rem;
}

.page-card p {
    margin: 0;
    color: var(--muted);
    font-size: 0.94rem;
    line-height: 1.62;
}

.section-cta {
    text-align: center;
    padding: 44px 0 54px;
}

.section-cta .btn-primary {
    min-width: 180px;
}

.section-cta p {
    color: var(--muted);
    margin-top: 10px;
}

.footer {
    background: var(--surface);
    border-top: 1px solid var(--line);
}

.footer-inner {
    padding: 20px 0 26px;
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    justify-content: space-between;
    color: var(--muted);
    font-size: 14px;
}

.footer-links {
    display: flex;
    gap: 14px;
}

.footer-links a {
    color: var(--accent-deep);
}

@media (min-width: 768px) {
    .hero {
        grid-template-columns: 1.15fr 0.85fr;
        padding-top: 74px;
    }

    .pages-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (min-width: 1280px) {
    .pages-grid {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }
}