:root {
    --blue: #1a73e8;
    --blue-dark: #1558b0;
    --text: #202124;
    --subtext: #5f6368;
    --bg: #f8f9fa;
    --white: #ffffff;
    --border: #e6e8eb;
    --shadow: 0 10px 30px rgba(0,0,0,.08);
    --radius: 20px;
    --max: 1180px;
}

* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text);
    background: var(--white);
    line-height: 1.65;
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

.container {
    width: min(var(--max), calc(100% - 32px));
    margin: 0 auto;
}

.topbar {
    position: sticky;
    top: 0;
    z-index: 50;
    backdrop-filter: blur(12px);
    background: rgba(255,255,255,.88);
    border-bottom: 1px solid rgba(0,0,0,.06);
}

.topbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 72px;
    gap: 20px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 700;
}

.brand-logo {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: conic-gradient(#ea4335 0 25%, #fbbc05 25% 50%, #34a853 50% 75%, #4285f4 75% 100%);
    position: relative;
    box-shadow: inset 0 0 0 3px #fff;
}

.brand-logo::after {
    content: "";
    position: absolute;
    inset: 8px;
    background: #4285f4;
    border-radius: 50%;
    box-shadow: inset 0 0 0 4px #fff;
}

.nav {
    display: flex;
    gap: 22px;
    color: var(--subtext);
    font-size: 15px;
}

.nav a:hover { color: var(--text); }

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 12px 32px;
    border-radius: 999px;
    font-weight: 700;
    transition: .2s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--blue);
    color: #fff;
    box-shadow: 0 10px 20px rgba(26,115,232,.25);
}

.btn-primary:hover { background: var(--blue-dark); transform: translateY(-1px); }

.btn-secondary {
    background: #fff;
    color: var(--blue);
    border: 1px solid rgba(26,115,232,.18);
}

.hero {
    padding: 72px 0 36px;
    background:
    radial-gradient(circle at top left, rgba(66,133,244,.08), transparent 30%),
    radial-gradient(circle at top right, rgba(52,168,83,.08), transparent 24%),
    linear-gradient(180deg, #f8fbff 0%, #fff 65%);
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.08fr .92fr;
    gap: 32px;
    align-items: center;
}

.eyebrow {
    display: inline-block;
    padding: 8px 14px;
    background: rgba(26,115,232,.08);
    color: var(--blue);
    border-radius: 999px;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 18px;
}

h1 {
    font-size: clamp(34px, 5vw, 58px);
    line-height: 1.08;
    margin: 0 0 18px;
    letter-spacing: -.02em;
}

.hero p {
    margin: 0 0 26px;
    color: var(--subtext);
    font-size: 18px;
    max-width: 640px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-bottom: 18px;
}

.notice {
    color: var(--subtext);
    font-size: 14px;
}

.preview {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 28px;
    box-shadow: var(--shadow);
    overflow: hidden;
}

.preview-top {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
    background: #fafafa;
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #d0d4d9;
}

.searchbar {
    flex: 1;
    margin-left: 8px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 10px 14px;
    color: #80868b;
    font-size: 14px;
}

.preview-body {
    padding: 28px;
    background: linear-gradient(180deg, #fff 0%, #f8fbff 100%);
}

.cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.mini-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 18px;
}

.mini-card strong {
    display: block;
    margin-bottom: 8px;
    font-size: 16px;
}

section {
    padding: 90px 0;
}

.section-head {
    text-align: center;
    max-width: 760px;
    margin: 0 auto 42px;
}

.section-head h2 {
    font-size: clamp(28px, 4vw, 42px);
    margin: 0 0 14px;
    line-height: 1.15;
}

.section-head p {
    margin: 0;
    color: var(--subtext);
    font-size: 17px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.feature-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: 0 6px 18px rgba(0,0,0,.04);
}

.icon {
    width: 50px;
    height: 50px;
    border-radius: 14px;
    background: rgba(26,115,232,.08);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--blue);
    font-size: 24px;
    margin-bottom: 18px;
}

.feature-card h3 {
    margin: 0 0 10px;
    font-size: 20px;
}

.feature-card p {
    margin: 0;
    color: var(--subtext);
    font-size: 15px;
}

.experience {
    background: var(--bg);
}

.experience-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 22px;
}

.exp-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 28px;
}

.exp-card h3 {
    margin: 0 0 10px;
    font-size: 22px;
}

.exp-card p {
    color: var(--subtext);
    margin: 0 0 14px;
}

.exp-card ul {
    margin: 0;
    padding-left: 18px;
    color: var(--text);
}

.download-banner {
    background: linear-gradient(135deg, #1a73e8, #4285f4 60%, #6ea8ff);
    color: #fff;
    border-radius: 30px;
    padding: 44px;
    align-items: center;
    box-shadow: var(--shadow);
    text-align: center;
}

.download-banner h2 {
    margin: 0 0 12px;
    font-size: clamp(28px, 4vw, 42px);
    line-height: 1.15;
}

.download-banner p {
    margin: 0 auto 18px;
    color: rgba(255,255,255,.92);
    max-width: 640px;
}

.download-box {
    background: rgba(255,255,255,.14);
    border: 1px solid rgba(255,255,255,.18);
    border-radius: 24px;
    padding: 24px;
    backdrop-filter: blur(8px);
}

.download-box .meta {
    display: grid;
    gap: 12px;
    color: rgba(255,255,255,.95);
    font-size: 14px;
    margin-top: 16px;
}

.faq-list {
    max-width: 920px;
    margin: 0 auto;
    display: grid;
    gap: 14px;
}

details {
    border: 1px solid var(--border);
    border-radius: 18px;
    background: #fff;
    padding: 18px 20px;
}

summary {
    cursor: pointer;
    font-weight: 700;
    list-style: none;
    position: relative;
    padding-right: 28px;
}

summary::-webkit-details-marker { display: none; }

summary::after {
    content: "+";
    position: absolute;
    right: 0;
    top: 0;
    color: var(--blue);
    font-size: 22px;
    line-height: 1;
}

details[open] summary::after {
    content: "–";
}

details p {
    margin: 14px 0 0;
    color: var(--subtext);
}

.footer {
    padding: 24px 0;
    color: var(--subtext);
    font-size: 14px;
    text-align: center;
}

@media (max-width: 980px) {
    .hero-grid,
    .feature-grid,
    .experience-grid,
    .download-banner {
    grid-template-columns: 1fr;
    }

    .feature-grid { gap: 16px; }
    .cards { grid-template-columns: 1fr; }
    .nav { display: none; }
}

@media (max-width: 640px) {
    .hero { padding-top: 40px; }
    .topbar-inner { min-height: 64px; }
    .download-banner { padding: 28px; }
    .preview-body { padding: 20px; }
    section { padding: 58px 0; }
}