/* =============================================
   YouTube中国官网 | youtubezw.net.cn
   设计系统：「管窥·LENS」Editorial Neo-Brutalism
   奶油 × 信号红 × 深海青 × 琥珀黄
   ============================================= */

:root {
    --ink: #1D1D2C;
    --cream: #FDF6EC;
    --paper: #F6EBDE;
    --red: #E63946;
    --teal: #178582;
    --amber: #FFB703;
    --white: #FFFFFF;
    --shadow: #1D1D2C;
}

/* ---------- 基础重置 ---------- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: system-ui, 'PingFang SC', 'Microsoft YaHei', sans-serif;
    overflow-x: hidden;
    background-color: var(--cream);
    background-image:
        radial-gradient(circle at 12% 10%, rgba(255, 183, 3, 0.09) 0%, transparent 40%),
        radial-gradient(circle at 88% 25%, rgba(23, 133, 130, 0.08) 0%, transparent 35%),
        radial-gradient(circle at 40% 100%, rgba(230, 57, 70, 0.05) 0%, transparent 50%);
    background-repeat: no-repeat;
    background-attachment: fixed;
    color: var(--ink);
    line-height: 1.6;
}

/* 颗粒质感 */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120' viewBox='0 0 120 120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='120' height='120' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
    pointer-events: none;
    z-index: 9999;
    mix-blend-mode: multiply;
}

::selection {
    background: var(--red);
    color: var(--white);
    text-shadow: none;
}

/* ---------- 核心布局 ---------- */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
}

.section {
    padding: 90px 0;
    position: relative;
}

.section:nth-child(even) {
    background:
        radial-gradient(circle at 1px 1px, rgba(29, 29, 44, 0.035) 1px, transparent 0),
        linear-gradient(180deg, rgba(253, 246, 236, 0) 0%, var(--paper) 100%);
    background-size: 28px 28px, cover;
}

.section:nth-child(even)::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 5px;
    background: repeating-linear-gradient(90deg,
        var(--red) 0 24px,
        var(--amber) 24px 48px,
        var(--teal) 48px 72px);
    opacity: 0.7;
}

/* ---------- 导航 ---------- */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(253, 246, 236, 0.92);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    border-bottom: 2px solid var(--ink);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
}

.header-inner::after {
    content: '';
    position: absolute;
    left: 24px;
    right: 24px;
    bottom: -2px;
    height: 3px;
    background: repeating-linear-gradient(90deg,
        var(--red) 0 30px,
        var(--teal) 30px 60px,
        var(--amber) 60px 90px);
    opacity: 0.5;
    pointer-events: none;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 800;
    font-size: 1.25rem;
    text-decoration: none;
    color: var(--ink);
    letter-spacing: -0.02em;
    line-height: 1.2;
    transition: opacity 0.2s;
}

.logo:hover .logo-icon {
    animation: icon-wiggle 0.5s ease-in-out infinite alternate;
}

@keyframes icon-wiggle {
    from { transform: scale(1) rotate(0deg); }
    to { transform: scale(1.12) rotate(-8deg); }
}

.logo-icon {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    background: var(--red);
    border: 2px solid var(--ink);
    box-shadow: 2px 2px 0 var(--ink);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    color: var(--white);
    position: relative;
    flex-shrink: 0;
}

.logo-icon::before {
    content: '▶';
    font-size: 0.7rem;
    margin-left: 2px;
}

/* 镜头眩光 */
.logo-icon::after {
    content: '';
    position: absolute;
    top: 4px;
    left: 6px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.6);
}

.logo-text {
    display: flex;
    flex-direction: column;
}

.logo-cn {
    font-size: 1.1rem;
    font-weight: 900;
    letter-spacing: 0.04em;
}

.logo-sub {
    font-size: 0.58rem;
    font-weight: 700;
    letter-spacing: 0.16em;
    color: var(--teal);
    text-transform: uppercase;
    margin-top: 1px;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 28px;
    list-style: none;
}

.main-nav a {
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--ink);
    transition: color 0.2s;
    position: relative;
    padding: 4px 0;
}

.main-nav a::before {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--red);
    border-radius: 2px;
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.35s cubic-bezier(0.65, 0, 0.35, 1);
}

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

.main-nav a:hover::before {
    transform: scaleX(1);
    transform-origin: left;
}

.main-nav .nav-cta {
    padding: 10px 24px;
    border-radius: 100px;
    background: var(--red);
    color: var(--white) !important;
    font-weight: 700;
    border: 2px solid var(--ink);
    box-shadow: 3px 3px 0 var(--ink);
    transition: transform 0.2s, box-shadow 0.2s, background 0.2s;
}

.main-nav .nav-cta::before {
    display: none;
}

.main-nav .nav-cta:hover {
    transform: translate(1px, 1px);
    box-shadow: 1px 1px 0 var(--ink);
    background: #d32f3c;
    color: var(--white) !important;
}

.menu-toggle {
    display: none;
    width: 44px;
    height: 44px;
    border: 2px solid var(--ink);
    border-radius: 12px;
    background: var(--white);
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 2px 2px 0 var(--ink);
    transition: all 0.2s;
}

.menu-toggle:hover {
    background: var(--amber);
}

.menu-toggle::before {
    content: '☰';
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--ink);
}

/* ---------- Hero ---------- */
.hero {
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
    position: relative;
    padding: 150px 0 100px;
    overflow: hidden;
    background: linear-gradient(115deg,
        var(--cream) 0%,
        var(--cream) 45%,
        #FBF0E2 100%);
}

/* 大镜头环 */
.hero::before {
    content: '';
    position: absolute;
    right: -140px;
    top: 50%;
    transform: translateY(-50%);
    width: 560px;
    height: 560px;
    border-radius: 50%;
    border: 3px dashed rgba(29, 29, 44, 0.18);
    background: radial-gradient(circle,
        rgba(255, 183, 3, 0.14) 0%,
        rgba(255, 183, 3, 0.04) 40%,
        transparent 70%);
    z-index: 1;
    pointer-events: none;
    animation: lens-rotate 90s linear infinite;
}

@keyframes lens-rotate {
    from { transform: translateY(-50%) rotate(0deg); }
    to { transform: translateY(-50%) rotate(360deg); }
}

/* 第二层镜头环 */
.hero::after {
    content: '';
    position: absolute;
    right: -30px;
    top: 50%;
    transform: translateY(-50%);
    width: 380px;
    height: 380px;
    border-radius: 50%;
    border: 3px solid rgba(29, 29, 44, 0.1);
    background: repeating-radial-gradient(circle,
        transparent 0 16px,
        rgba(29, 29, 44, 0.05) 16px 18px);
    pointer-events: none;
    z-index: 1;
}

.hero-content {
    max-width: 680px;
    position: relative;
    z-index: 5;
}

.hero-eyebrow {
    display: inline-block;
    font-size: 0.78rem;
    font-weight: 800;
    padding: 6px 18px;
    border-radius: 100px;
    margin-bottom: 22px;
    background: var(--teal);
    color: var(--white);
    border: 2px solid var(--ink);
    box-shadow: 3px 3px 0 var(--ink);
    text-transform: uppercase;
    letter-spacing: 0.14em;
}

.hero h1 {
    font-size: 3.2rem;
    line-height: 1.12;
    margin-bottom: 22px;
    font-weight: 900;
    letter-spacing: -0.02em;
}

.hero h1 .highlight {
    color: var(--red);
    position: relative;
    display: inline-block;
}

.hero h1 .highlight::after {
    content: '';
    position: absolute;
    bottom: 6px;
    left: 0;
    width: 100%;
    height: 10px;
    background: rgba(255, 183, 3, 0.55);
    z-index: -1;
    border-radius: 6px;
}

.hero p {
    font-size: 1.15rem;
    opacity: 0.72;
    color: var(--ink);
    max-width: 560px;
    margin-bottom: 38px;
    line-height: 1.75;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-image {
    position: relative;
    z-index: 4;
    width: 380px;
    height: 380px;
    border-radius: 50%;
    overflow: hidden;
    border: 4px solid var(--ink);
    box-shadow:
        10px 10px 0 var(--red),
        20px 20px 0 rgba(29, 29, 44, 0.08);
    flex-shrink: 0;
    margin-right: 60px;
    background: var(--amber);
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.hero-image:hover {
    transform: scale(1.02) rotate(1deg);
    box-shadow:
        12px 12px 0 var(--red),
        24px 24px 0 rgba(29, 29, 44, 0.08);
}

.hero-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

/* ---------- 按钮 ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 32px;
    border-radius: 100px;
    font-weight: 700;
    cursor: pointer;
    border: 2px solid var(--ink);
    text-decoration: none;
    transition: transform 0.2s, box-shadow 0.2s, background 0.2s, color 0.2s;
    font-size: 0.95rem;
    letter-spacing: 0.02em;
    line-height: 1.4;
}

.btn-primary {
    background: var(--red);
    color: var(--white);
    box-shadow: 4px 4px 0 var(--ink);
}

.btn-primary:hover {
    transform: translate(1px, 1px);
    box-shadow: 2px 2px 0 var(--ink);
    background: #d32f3c;
}

.btn-primary:active {
    transform: translate(2px, 2px);
    box-shadow: 0 0 0 var(--ink);
}

.btn-outline {
    background: var(--white);
    border-color: var(--ink);
    color: var(--ink);
    box-shadow: 4px 4px 0 var(--ink);
}

.btn-outline:hover {
    transform: translate(1px, 1px);
    box-shadow: 2px 2px 0 var(--ink);
    background: var(--amber);
}

.btn-outline:active {
    transform: translate(2px, 2px);
    box-shadow: 0 0 0 var(--ink);
}

/* ---------- 标签/标题 ---------- */
.section-label {
    display: inline-block;
    font-size: 0.74rem;
    font-weight: 800;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    margin-bottom: 14px;
    padding: 6px 18px;
    border-radius: 100px;
    background: var(--amber);
    color: var(--ink);
    border: 2px solid var(--ink);
    box-shadow: 2px 2px 0 var(--ink);
}

.section-title {
    font-size: 2.4rem;
    font-weight: 900;
    margin-bottom: 14px;
    letter-spacing: -0.015em;
    line-height: 1.25;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 68px;
    height: 5px;
    background: var(--red);
    border-radius: 4px;
    margin-top: 12px;
}

.section-desc {
    max-width: 620px;
    opacity: 0.72;
    color: var(--ink);
    margin-bottom: 48px;
    font-size: 1.05rem;
    line-height: 1.7;
}

/* ---------- 卡片网格 ---------- */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 28px;
}

.category-card {
    background: var(--white);
    border: 2px solid var(--ink);
    border-radius: 18px;
    padding: 32px 28px 28px;
    box-shadow: 6px 6px 0 var(--ink);
    transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.25s;
    position: relative;
    overflow: hidden;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 6px;
    background: linear-gradient(90deg, var(--red) 0%, var(--amber) 50%, var(--teal) 100%);
}

.category-card:hover {
    transform: translate(-3px, -3px);
    box-shadow: 9px 9px 0 var(--ink);
}

.category-card:active {
    transform: translate(2px, 2px);
    box-shadow: 2px 2px 0 var(--ink);
}

.card-icon {
    width: 56px;
    height: 56px;
    border-radius: 16px;
    background: var(--teal);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 18px;
    font-size: 1.5rem;
    color: var(--white);
    border: 2px solid var(--ink);
    box-shadow: 3px 3px 0 var(--ink);
    position: relative;
}

.card-icon::after {
    content: '';
    position: absolute;
    top: 4px;
    left: 6px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.35);
}

.category-card:nth-child(2) .card-icon { background: var(--red); }
.category-card:nth-child(3) .card-icon { background: var(--amber); color: var(--ink); }
.category-card:nth-child(4) .card-icon { background: var(--teal); }

.category-card h3 {
    font-size: 1.15rem;
    font-weight: 800;
    margin-bottom: 6px;
    letter-spacing: -0.01em;
}

.category-card p {
    font-size: 0.9rem;
    opacity: 0.6;
    line-height: 1.6;
    margin-bottom: 14px;
}

.card-link {
    font-weight: 700;
    font-size: 0.85rem;
    text-decoration: none;
    color: var(--teal);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin-top: auto;
    transition: gap 0.25s, color 0.25s;
}

.card-link:hover {
    gap: 12px;
    color: var(--red);
}

/* ---------- 特性块 ---------- */
.feature-block {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.feature-image {
    border-radius: 24px;
    overflow: hidden;
    border: 3px solid var(--ink);
    box-shadow: 8px 8px 0 var(--ink);
    position: relative;
    background: var(--white);
}

.feature-image::after {
    content: '▶';
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: var(--white);
    background: rgba(230, 57, 70, 0.35);
    backdrop-filter: blur(2px);
    text-shadow: 0 3px 8px rgba(0, 0, 0, 0.35);
    transition: background 0.3s;
}

.feature-image:hover::after {
    background: rgba(230, 57, 70, 0.15);
}

.feature-image img {
    width: 100%;
    height: auto;
    display: block;
}

.feature-text h3 {
    font-size: 1.6rem;
    font-weight: 900;
    margin-bottom: 16px;
    line-height: 1.3;
}

.feature-text > p {
    opacity: 0.68;
    line-height: 1.7;
    margin-bottom: 20px;
}

.feature-list {
    list-style: none;
    margin-top: 24px;
}

.feature-list li {
    padding: 8px 0;
    display: flex;
    align-items: center;
    gap: 14px;
    font-weight: 600;
    font-size: 1rem;
}

.feature-list li::before {
    content: '✓';
    font-weight: 900;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--amber);
    border: 2px solid var(--ink);
    color: var(--ink);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    flex-shrink: 0;
    box-shadow: 2px 2px 0 var(--ink);
}

/* ---------- 数据条 ---------- */
.stats-bar {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 28px;
    text-align: center;
}

.stat-item {
    background: var(--white);
    border: 2px solid var(--ink);
    border-radius: 20px;
    padding: 32px 20px;
    box-shadow: 5px 5px 0 var(--ink);
    position: relative;
    overflow: hidden;
    transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.stat-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: var(--red);
}

.stat-item:nth-child(2)::before { background: var(--teal); }
.stat-item:nth-child(3)::before { background: var(--amber); }
.stat-item:nth-child(4)::before { background: var(--red); }

.stat-item:hover {
    transform: translateY(-6px);
}

.stat-number {
    font-size: 2.6rem;
    font-weight: 900;
    color: var(--red);
    letter-spacing: -0.03em;
    line-height: 1.1;
    font-variant-numeric: tabular-nums;
    display: block;
}

.stat-label {
    font-size: 0.85rem;
    font-weight: 700;
    opacity: 1;
    color: var(--teal);
    margin-top: 8px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* ---------- 内容墙 ---------- */
.content-wall {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 28px;
}

.content-wall-item {
    background: var(--white);
    border: 2px solid var(--ink);
    border-radius: 18px;
    overflow: hidden;
    transition: transform 0.25s, box-shadow 0.25s;
    box-shadow: 4px 4px 0 var(--ink);
    position: relative;
    display: flex;
    flex-direction: column;
}

.content-wall-item:hover {
    transform: translateY(-5px);
    box-shadow: 8px 8px 0 var(--ink);
}

.content-wall-item img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    display: block;
    border-bottom: 2px solid var(--ink);
}

/* 悬浮播放按钮 */
.content-wall-item::after {
    content: '▶';
    position: absolute;
    top: 88px;
    right: 16px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: rgba(230, 57, 70, 0.94);
    border: 2px solid var(--ink);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    color: var(--white);
    box-shadow: 2px 2px 0 var(--ink);
    transition: transform 0.2s, background 0.2s;
}

.content-wall-item:hover::after {
    transform: scale(1.15);
    background: var(--amber);
    color: var(--ink);
}

.content-wall-body {
    padding: 22px 20px 26px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.content-wall-body h4 {
    font-size: 1.05rem;
    font-weight: 800;
    margin-bottom: 6px;
    line-height: 1.4;
}

.content-wall-body p {
    font-size: 0.88rem;
    opacity: 0.6;
    line-height: 1.6;
    margin-bottom: 12px;
}

.content-wall-body .meta {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--teal);
    margin-top: auto;
    padding-top: 12px;
    border-top: 1px dashed rgba(29, 29, 44, 0.15);
}

/* ---------- FAQ ---------- */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border: 2px solid var(--ink);
    border-radius: 16px;
    margin-bottom: 16px;
    overflow: hidden;
    cursor: pointer;
    background: var(--white);
    transition: box-shadow 0.25s, border-color 0.25s;
}

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

.faq-item.open {
    box-shadow: 6px 6px 0 var(--ink);
    border-color: var(--ink);
}

.faq-item .faq-question {
    padding: 20px 24px;
    font-weight: 800;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    font-size: 1.05rem;
    line-height: 1.4;
}

.faq-item .faq-question::after {
    content: '+';
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--red);
    transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
    flex-shrink: 0;
    line-height: 1;
}

.faq-item.open .faq-question::after {
    transform: rotate(135deg);
    color: var(--teal);
}

.faq-item .faq-answer {
    padding: 0 24px 22px;
    opacity: 0.72;
    font-size: 0.98rem;
    line-height: 1.7;
    display: none;
}

.faq-item.open .faq-answer {
    display: block;
    animation: faq-fade 0.35s ease;
}

@keyframes faq-fade {
    from { opacity: 0; transform: translateY(-6px); }
    to { opacity: 0.72; transform: translateY(0); }
}

/* ---------- CTA横幅 ---------- */
.cta-banner {
    padding: 64px 24px;
    text-align: center;
    border-radius: 28px;
    background: linear-gradient(135deg, var(--red) 0%, #e8545d 100%);
    border: 3px solid var(--ink);
    box-shadow: 10px 10px 0 var(--ink);
    position: relative;
    overflow: hidden;
}

/* 装饰元素 */
.cta-banner::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 18% 50%, rgba(255, 183, 3, 0.55) 0%, transparent 30%),
        radial-gradient(circle at 82% 40%, rgba(255, 255, 255, 0.18) 0%, transparent 25%),
        repeating-linear-gradient(45deg, transparent 0 14px, rgba(255, 255, 255, 0.05) 14px 16px);
    pointer-events: none;
}

.cta-banner::after {
    content: '▶';
    position: absolute;
    bottom: -18px;
    right: 48px;
    font-size: 5rem;
    color: rgba(255, 255, 255, 0.18);
    text-shadow: 2px 2px 0 var(--ink);
    line-height: 1;
}

.cta-banner h2 {
    color: var(--white);
    position: relative;
    font-size: 2.2rem;
    font-weight: 900;
    letter-spacing: -0.015em;
    margin-bottom: 14px;
    text-shadow: 3px 3px 0 rgba(0, 0, 0, 0.18);
    line-height: 1.25;
}

.cta-banner p {
    position: relative;
    opacity: 0.92;
    color: var(--white);
    margin-bottom: 28px;
    max-width: 480px;
    margin-left: auto;
    margin-right: auto;
    font-size: 1.05rem;
}

.cta-banner .btn-primary {
    background: var(--white);
    color: var(--red);
    border: 2px solid var(--ink);
    box-shadow: 4px 4px 0 var(--ink);
    position: relative;
    z-index: 2;
}

.cta-banner .btn-primary:hover {
    background: var(--amber);
    color: var(--ink);
    box-shadow: 2px 2px 0 var(--ink);
}

/* ---------- 页脚 ---------- */
.site-footer {
    padding: 64px 0 28px;
    background:
        radial-gradient(circle at 80% 100%, rgba(23, 133, 130, 0.08) 0%, transparent 50%),
        #EAF2EF;
    border-top: 3px solid var(--ink);
    position: relative;
    margin-top: 40px;
}

.site-footer::before {
    content: '';
    position: absolute;
    top: -3px;
    left: 0;
    width: 100%;
    height: 4px;
    background: repeating-linear-gradient(90deg,
        var(--red) 0 40px,
        var(--teal) 40px 80px,
        var(--amber) 80px 120px);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 48px;
}

.footer-brand {
    padding-right: 24px;
}

.footer-brand .logo {
    margin-bottom: 12px;
}

.footer-brand p {
    font-size: 0.9rem;
    opacity: 0.58;
    margin-top: 12px;
    line-height: 1.7;
}

.footer-col h5 {
    font-weight: 800;
    font-size: 0.9rem;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--teal);
}

.footer-col a {
    display: block;
    text-decoration: none;
    color: var(--ink);
    opacity: 0.65;
    padding: 5px 0;
    font-size: 0.92rem;
    transition: opacity 0.2s, color 0.2s, padding-left 0.2s;
}

.footer-col a:hover {
    opacity: 1;
    color: var(--red);
    padding-left: 6px;
}

.footer-bottom {
    border-top: 2px solid rgba(29, 29, 44, 0.1);
    margin-top: 48px;
    padding-top: 22px;
    text-align: center;
    font-size: 0.82rem;
    opacity: 0.6;
}

/* ---------- 工具类 ---------- */
.text-accent {
    color: var(--red);
}

.text-center {
    text-align: center;
}

.text-center .section-title::after,
.text-center .section-label {
    margin-left: auto;
    margin-right: auto;
}

.seo-description {
    max-width: 600px;
    margin: 0 auto 48px;
    opacity: 0.7;
    text-align: center;
    line-height: 1.7;
}

.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }

/* ---------- 响应式 ---------- */
@media (max-width: 768px) {
    .hero {
        flex-direction: column;
        text-align: center;
        padding: 120px 0 60px;
        gap: 40px;
    }

    .hero-content {
        max-width: 100%;
    }

    .hero p {
        margin-left: auto;
        margin-right: auto;
    }

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

    .hero-image {
        width: 280px;
        height: 280px;
        margin: 20px auto 0;
    }

    .hero::before {
        right: -180px;
        width: 380px;
        height: 380px;
    }

    .hero::after {
        display: none;
    }

    .feature-block {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .feature-image {
        order: -1;
    }

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

    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }

    .main-nav {
        display: none;
    }

    .menu-toggle {
        display: flex;
    }

    .main-nav.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 12px;
        right: 12px;
        background: var(--cream);
        border: 2px solid var(--ink);
        border-radius: 18px;
        box-shadow: 6px 6px 0 var(--ink);
        padding: 24px;
        gap: 8px;
        align-items: stretch;
        z-index: 999;
    }

    .main-nav.open a {
        padding: 12px 16px;
        border-radius: 10px;
        border-bottom: none;
        font-size: 1rem;
    }

    .main-nav.open a:hover {
        background: var(--amber);
    }

    .main-nav.open .nav-cta {
        text-align: center;
        margin-top: 8px;
        border-radius: 100px;
    }

    .section-title {
        font-size: 1.9rem;
    }

    .cta-banner {
        padding: 48px 20px;
        border-radius: 20px;
    }

    .cta-banner h2 {
        font-size: 1.6rem;
    }
}

@media (max-width: 480px) {
    .cards-grid,
    .content-wall,
    .stats-bar {
        grid-template-columns: 1fr;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
    }

    .hero-buttons .btn {
        justify-content: center;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .hero-image {
        width: 220px;
        height: 220px;
        margin: 20px auto 0;
        margin-right: 0;
    }

    .hero::before {
        right: -140px;
        width: 300px;
        height: 300px;
    }

    .section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .stat-number {
        font-size: 2rem;
    }

    .cta-banner::after {
        right: 12px;
        bottom: -10px;
        font-size: 3.5rem;
    }

    .footer-grid {
        gap: 28px;
    }

    .cta-banner .btn-primary {
        width: 100%;
        justify-content: center;
    }
}