:root {
    --primary: #2563eb;
    --dark: #0f172a;
    --gray: #e2e8f0;
    --light: #f8fafc;
    --text: #1e293b;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text);
    background: var(--light);
    line-height: 1.6;
}

img {
    max-width: 100%;
    display: block;
}

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

.hero {
    background: linear-gradient(135deg, #eef2ff, #dbeafe);
    padding: 2.5rem clamp(1rem, 5vw, 5rem) 3.5rem;
}

.hero-sub {
    padding-bottom: 2.5rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.logo-mark {
    width: 64px;
    height: 64px;
    border-radius: 16px;
    background: var(--dark);
    color: #fff;
    display: grid;
    place-items: center;
    font-weight: 700;
    letter-spacing: 1px;
}

.logo-text p {
    margin: 0;
    font-size: 1.25rem;
    font-weight: 600;
}

.logo-text span {
    font-size: 0.9rem;
    color: #475569;
}

.hero-nav {
    margin-top: 1.5rem;
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    font-weight: 600;
}

.hero-nav a {
    padding: 0.4rem 1rem;
    border-radius: 999px;
    transition: background 0.2s;
}

.hero-nav a[aria-current="page"] {
    background: var(--primary);
    color: #fff;
}

.hero-nav a:hover,
.hero-nav a:focus-visible {
    background: rgba(37, 99, 235, 0.12);
}

.hero-content {
    margin-top: 2.5rem;
    max-width: 640px;
}

.hero-content h1 {
    margin: 0 0 1rem;
    font-size: clamp(2rem, 5vw, 3.5rem);
    line-height: 1.2;
}

.hero-content p {
    margin: 0 0 1.5rem;
    color: #475569;
}

.cta {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.85rem 1.8rem;
    border-radius: 999px;
    background: var(--primary);
    color: #fff;
    font-weight: 600;
}

.section {
    padding: 3.5rem clamp(1rem, 5vw, 5rem);
}

.section-header h2 {
    margin: 0;
    font-size: 2rem;
}

.section-header p {
    margin: 0.4rem 0 2rem;
    color: #475569;
}

.features,
.price-grid,
.faq {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
}

.features article,
.faq article {
    background: #fff;
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.05);
}

.download-meta {
    list-style: none;
    padding: 0;
    margin: 0.5rem 0 1rem;
    color: #475569;
}

.download-meta li {
    padding: 0.25rem 0;
}

.note {
    margin-top: 1.5rem;
    font-size: 0.95rem;
    color: #0f172a;
    background: #e0f2fe;
    padding: 0.75rem 1rem;
    border-radius: 10px;
}

.link-grid article {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.link-grid .btn {
    align-self: flex-start;
    margin-top: 0.5rem;
}

.pricing {
    background: #fff;
}

.price-grid article {
    border-radius: 18px;
    padding: 2rem;
    border: 1px solid var(--gray);
    background: #fff;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.price-grid .highlight {
    border: 2px solid var(--primary);
    box-shadow: 0 20px 40px rgba(37, 99, 235, 0.15);
}

.price-grid .price {
    margin: 0;
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
}

.price-grid ul {
    list-style: none;
    padding: 0;
    margin: 0;
    color: #475569;
}

.price-grid li {
    padding: 0.3rem 0;
}

.btn {
    margin-top: auto;
    display: inline-flex;
    justify-content: center;
    padding: 0.75rem 1.2rem;
    border-radius: 10px;
    border: 1px solid var(--primary);
    color: var(--primary);
    font-weight: 600;
}

.btn.secondary {
    background: var(--primary);
    color: #fff;
}

.help {
    background: var(--light);
}

.contact {
    background: #0f172a;
    color: #e2e8f0;
}

.contact .section-header p {
    color: #cbd5f5;
}

.contact-card {
    background: #fff;
    border: 1px solid rgba(15, 23, 42, 0.08);
    border-radius: 20px;
    padding: 2rem;
    line-height: 2;
    color: inherit;
}

.contact .contact-card {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.footer {
    padding: 1.5rem;
    text-align: center;
    font-size: 0.9rem;
    color: #94a3b8;
}

@media (min-width: 900px) {
    .hero {
        display: grid;
        grid-template-columns: 1fr auto;
        align-items: start;
        gap: 2rem;
    }

    .hero-content {
        grid-column: 1 / -1;
        max-width: none;
    }

    .hero-nav {
        justify-self: end;
    }
}

@media (max-width: 600px) {
    .logo-mark {
        width: 54px;
        height: 54px;
    }

    .hero-nav {
        justify-content: center;
    }

    .cta {
        width: 100%;
    }
}