/* ==========================================================================
   Gamma 落地页独立样式（无任何第三方 CSS 框架）
   主题：深色背景 + 紫色主按钮
   ========================================================================== */

/* ---------- 变量与基础 ---------- */
:root {
    --bg-page: #0a0a10;
    --bg-surface: #101019;
    --bg-card: #14141f;
    --bg-card-hover: #181826;

    --text-primary: #f4f4f8;
    --text-secondary: #a2a2b8;
    --text-faint: #73738a;

    --accent: #7c3aed;
    --accent-deep: #6d28d9;
    --accent-light: #a78bfa;
    --accent-soft: rgba(124, 58, 237, 0.14);
    --accent-border: rgba(124, 58, 237, 0.45);

    --gradient-primary: linear-gradient(135deg, #6d28d9 0%, #7c3aed 45%, #a855f7 100%);
    --gradient-text: linear-gradient(120deg, #a78bfa 0%, #c084fc 60%, #e879f9 100%);

    --border: rgba(255, 255, 255, 0.08);
    --radius-lg: 20px;
    --radius-md: 14px;
    --radius-sm: 10px;

    --shadow-card: 0 12px 32px rgba(0, 0, 0, 0.35);
    --shadow-purple: 0 8px 26px rgba(124, 58, 237, 0.38);

    --header-height: 68px;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
    background: var(--bg-page);
    color: var(--text-primary);
    font-size: 16px;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

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

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

ul {
    list-style: none;
}

::selection {
    background: rgba(124, 58, 237, 0.55);
    color: #fff;
}

a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--accent-light);
    outline-offset: 3px;
    border-radius: 6px;
}

/* ---------- 通用容器 ---------- */
.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 24px;
}

section[id] {
    scroll-margin-top: calc(var(--header-height) + 12px);
}

.section {
    padding: 92px 0;
}

.bg-dark-surface {
    background:
        radial-gradient(900px 300px at 50% 0%, rgba(124, 58, 237, 0.07), transparent 70%),
        var(--bg-surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

/* ---------- 标题 ---------- */
.section-title {
    font-size: clamp(26px, 4vw, 36px);
    font-weight: 800;
    text-align: center;
    letter-spacing: 0.5px;
    margin-bottom: 14px;
}

.section-sub {
    font-size: 17px;
    color: var(--text-secondary);
    text-align: center;
    max-width: 720px;
    margin: 0 auto 56px;
    line-height: 1.7;
}

/* ---------- 顶部导航 ---------- */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(10, 10, 16, 0.82);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
}

.nav-container {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 21px;
    font-weight: 800;
    letter-spacing: 0.5px;
}

.logo-icon {
    width: 34px;
    height: 34px;
    border-radius: 9px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.logo-icon img {
    width: 26px;
    height: 26px;
    object-fit: contain;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 34px;
}

.nav-menu a {
    font-size: 15px;
    color: var(--text-secondary);
    transition: color 0.2s ease;
    position: relative;
    padding: 4px 0;
}

.nav-menu a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -2px;
    width: 0;
    height: 2px;
    border-radius: 2px;
    background: var(--gradient-primary);
    transition: width 0.25s ease;
}

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

.nav-menu a:hover::after {
    width: 100%;
}

/* ---------- Hero ---------- */
.hero {
    position: relative;
    padding: 110px 0 100px;
    text-align: center;
    overflow: hidden;
}

.hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(640px 340px at 50% -8%, rgba(124, 58, 237, 0.32), transparent 68%),
        radial-gradient(420px 260px at 82% 18%, rgba(168, 85, 247, 0.14), transparent 70%),
        radial-gradient(420px 260px at 14% 22%, rgba(109, 40, 217, 0.16), transparent 70%);
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 7px 18px;
    border-radius: 999px;
    font-size: 14px;
    color: var(--accent-light);
    background: var(--accent-soft);
    border: 1px solid var(--accent-border);
    margin-bottom: 28px;
}

.hero h1 {
    font-size: clamp(30px, 4.8vw, 50px);
    font-weight: 800;
    line-height: 1.22;
    letter-spacing: 1px;
    margin-bottom: 24px;
    color: #ffffff;
}

.hero h1 .grad {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}

.hero-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.85;
    max-width: 760px;
    margin: 0 auto;
}

.btn-group {
    margin-top: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
}

/* ---------- 按钮（整体紫色风格） ---------- */
.btn-primary,
.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 15px 40px;
    border-radius: 999px;
    font-size: 16px;
    font-weight: 700;
    letter-spacing: 0.5px;
    cursor: pointer;
    border: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #ffffff;
    box-shadow: var(--shadow-purple);
}

.btn-primary:hover {
    transform: translateY(-2px);
    filter: brightness(1.1);
    box-shadow: 0 12px 32px rgba(124, 58, 237, 0.5);
}

.btn-secondary {
    background: rgba(124, 58, 237, 0.12);
    color: var(--accent-light);
    border: 1px solid var(--accent-border);
}

.btn-secondary:hover {
    transform: translateY(-2px);
    background: rgba(124, 58, 237, 0.22);
}

.hero-trust {
    margin-top: 46px;
    font-size: 14px;
    color: var(--text-faint);
}

/* ---------- 简介段落 ---------- */
.intro-text {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
    color: var(--text-secondary);
    font-size: 17px;
    line-height: 1.9;
}

/* ---------- 功能卡片 ---------- */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 34px 28px;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease,
        background 0.25s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-border);
    background: var(--bg-card-hover);
    box-shadow: var(--shadow-card);
}

.feature-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    background: var(--accent-soft);
    border: 1px solid var(--accent-border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 26px;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 19px;
    font-weight: 700;
    margin-bottom: 12px;
}

.feature-card p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.75;
}

/* ---------- 场景卡片 ---------- */
.case-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.case-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent);
    border-radius: var(--radius-md);
    padding: 30px 30px;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.case-item:hover {
    transform: translateY(-4px);
    border-color: var(--accent-border);
    border-left-color: var(--accent-light);
    box-shadow: var(--shadow-card);
}

.case-item h3 {
    font-size: 19px;
    font-weight: 700;
    margin-bottom: 12px;
}

.case-item p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ---------- 视频教程 ---------- */
.video-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.video-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.video-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-border);
    box-shadow: var(--shadow-card);
}

.video-wrapper {
    position: relative;
    width: 100%;
    aspect-ratio: 16 / 9;
    background: #000;
}

.video-wrapper iframe {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

.video-info {
    padding: 20px 22px 24px;
}

.video-info h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
    line-height: 1.5;
}

.video-info p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ---------- 步骤 ---------- */
.step-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.step-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px 26px;
    text-align: center;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.step-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-border);
    box-shadow: var(--shadow-card);
}

.step-number {
    width: 52px;
    height: 52px;
    margin: 0 auto 18px;
    border-radius: 50%;
    background: var(--gradient-primary);
    color: #fff;
    font-size: 22px;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-purple);
}

.step-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
}

.step-card p {
    font-size: 14.5px;
    color: var(--text-secondary);
    line-height: 1.75;
}

/* ---------- 优势 ---------- */
.advantage-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.advantage-block {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px 30px;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.advantage-block:hover {
    transform: translateY(-4px);
    border-color: var(--accent-border);
    box-shadow: var(--shadow-card);
}

.advantage-block h3 {
    font-size: 19px;
    font-weight: 700;
    margin-bottom: 12px;
}

.advantage-block p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ---------- FAQ ---------- */
.faq-wrap {
    max-width: 860px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px 28px;
    transition: border-color 0.25s ease;
}

.faq-item:hover {
    border-color: var(--accent-border);
}

.faq-item h3 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--accent-light);
}

.faq-item p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ---------- 底部 CTA ---------- */
.cta-section {
    position: relative;
    padding: 84px 0;
    text-align: center;
    overflow: hidden;
    background:
        radial-gradient(700px 320px at 50% 0%, rgba(124, 58, 237, 0.28), transparent 70%),
        radial-gradient(520px 280px at 50% 110%, rgba(168, 85, 247, 0.16), transparent 70%),
        var(--bg-page);
    border-top: 1px solid var(--border);
}

.cta-section h2 {
    font-size: clamp(28px, 4vw, 38px);
    font-weight: 800;
    margin-bottom: 16px;
}

.cta-section h2 .grad {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}

.cta-section p {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 34px;
}

/* ---------- 页脚 ---------- */
.footer {
    border-top: 1px solid var(--border);
    padding: 44px 0;
    text-align: center;
    color: var(--text-faint);
    font-size: 15px;
    background: var(--bg-surface);
}

.footer .footer-sub {
    margin-top: 12px;
    font-size: 14px;
}

/* ---------- 响应式 ---------- */
@media (max-width: 1000px) {
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }

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

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

@media (max-width: 760px) {
    .nav-menu {
        display: none;
    }

    .section {
        padding: 68px 0;
    }

    .hero {
        padding: 76px 0 72px;
    }

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

    .grid-3,
    .video-grid,
    .step-grid,
    .case-grid,
    .advantage-list {
        grid-template-columns: 1fr;
    }

    .btn-primary,
    .btn-secondary {
        width: 100%;
        max-width: 320px;
    }

    .section-sub {
        margin-bottom: 40px;
    }
}