/* ====================================================================
   蓝海选品 — 宣传官网样式表
   ==================================================================== */

/* ---- 设计令牌 ---- */
:root {
    --color-primary: #1a73e8;
    --color-primary-dark: #1557b0;
    --color-primary-light: #4a9af0;
    --color-primary-bg: #e8f0fe;
    --color-accent: #00c853;
    --color-accent-dark: #00a844;
    --color-bg: #f8f9fa;
    --color-bg-alt: #ffffff;
    --color-text: #1a1a2e;
    --color-text-secondary: #555;
    --color-text-muted: #888;
    --color-border: #e0e0e0;
    --color-border-light: #f0f0f0;
    --color-orange: #ff9800;
    --color-purple: #7c3aed;
    --color-red: #e53935;
    --color-teal: #00897b;

    --font-sans: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;

    --shadow-sm: 0 1px 3px rgba(0,0,0,.08);
    --shadow-md: 0 4px 16px rgba(0,0,0,.10);
    --shadow-lg: 0 8px 32px rgba(0,0,0,.12);
    --shadow-xl: 0 16px 48px rgba(0,0,0,.16);

    --transition-fast: .2s ease;
    --transition-base: .3s ease;
    --transition-slow: .5s ease;

    --container-max: 1200px;
    --container-narrow: 760px;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

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

ul {
    list-style: none;
}

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

/* ---- 容器 ---- */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
}

.container-narrow {
    max-width: var(--container-narrow);
    margin: 0 auto;
    padding: 0 24px;
}

/* ---- 通用按钮 ---- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    border-radius: var(--radius-sm);
    font-size: .95rem;
    font-weight: 600;
    cursor: pointer;
    border: 2px solid transparent;
    transition: all var(--transition-base);
    white-space: nowrap;
}

.btn-lg {
    padding: 16px 40px;
    font-size: 1.05rem;
}

.btn-block {
    display: flex;
    width: 100%;
}

.btn-primary {
    background: var(--color-primary);
    color: #fff;
    box-shadow: 0 4px 14px rgba(26,115,232,.35);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    box-shadow: 0 6px 20px rgba(26,115,232,.45);
    transform: translateY(-2px);
}

.btn-accent {
    background: var(--color-accent);
    color: #fff;
    box-shadow: 0 4px 14px rgba(0,200,83,.35);
}

.btn-accent:hover {
    background: var(--color-accent-dark);
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-outline:hover {
    background: var(--color-primary);
    color: #fff;
    transform: translateY(-2px);
}

/* ====================================================================
   导航栏
   ==================================================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(255,255,255,.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border-light);
    transition: all var(--transition-base);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 68px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
}

.logo-icon {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    position: relative;
    flex-shrink: 0;
}

.logo-icon::after {
    content: "";
    position: absolute;
    inset: 6px;
    border-radius: 4px;
    background: #fff;
    clip-path: polygon(0 100%, 40% 50%, 60% 75%, 100% 0, 100% 100%);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    padding: 8px 16px;
    font-size: .95rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-primary);
    background: var(--color-primary-bg);
}

.nav-cta {
    margin-left: 8px;
    padding: 10px 24px;
    background: var(--color-primary);
    color: #fff;
    font-weight: 600;
    border-radius: var(--radius-sm);
    transition: all var(--transition-base);
}

.nav-cta:hover {
    background: var(--color-primary-dark);
    transform: translateY(-1px);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 6px;
}

.hamburger span {
    width: 24px;
    height: 2.5px;
    background: var(--color-text);
    border-radius: 2px;
    transition: all var(--transition-base);
}

.hamburger.active span:nth-child(1) {
    transform: translateY(7.5px) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: translateY(-7.5px) rotate(-45deg);
}

/* ====================================================================
   Hero 区
   ==================================================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
    padding-top: 68px;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, #e8f0fe 0%, #f0fdf4 50%, #f8f9fa 100%);
    z-index: 0;
}

.hero-bg::before {
    content: "";
    position: absolute;
    top: -10%;
    right: -5%;
    width: 500px;
    height: 500px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(26,115,232,.12), transparent 70%);
}

.hero-bg::after {
    content: "";
    position: absolute;
    bottom: -10%;
    left: -5%;
    width: 400px;
    height: 400px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(0,200,83,.10), transparent 70%);
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.hero-badge {
    display: inline-block;
    padding: 8px 20px;
    background: rgba(26,115,232,.10);
    color: var(--color-primary);
    font-size: .85rem;
    font-weight: 600;
    border-radius: 999px;
    margin-bottom: 24px;
    animation: fadeInUp .6s ease both;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    letter-spacing: -.02em;
    background: linear-gradient(135deg, var(--color-primary) 0%, #1a1a2e 60%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 12px;
    animation: fadeInUp .6s ease .1s both;
}

.hero-subtitle {
    font-size: clamp(1.2rem, 3vw, 1.8rem);
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 16px;
    animation: fadeInUp .6s ease .2s both;
}

.hero-desc {
    font-size: 1.05rem;
    color: var(--color-text-secondary);
    margin-bottom: 36px;
    animation: fadeInUp .6s ease .3s both;
}

.hero-cta-group {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 60px;
    animation: fadeInUp .6s ease .4s both;
}

.hero-stats {
    display: flex;
    gap: 48px;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp .6s ease .5s both;
}

.hero-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
    color: var(--color-primary);
}

.stat-label {
    font-size: .85rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

/* ====================================================================
   通用 Section
   ==================================================================== */
.section {
    padding: 96px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-tag {
    display: inline-block;
    padding: 4px 14px;
    background: var(--color-primary-bg);
    color: var(--color-primary);
    font-size: .8rem;
    font-weight: 700;
    letter-spacing: .05em;
    border-radius: 999px;
    margin-bottom: 16px;
    text-transform: uppercase;
}

.section-title {
    font-size: clamp(1.8rem, 4vw, 2.6rem);
    font-weight: 800;
    letter-spacing: -.02em;
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
}

/* ====================================================================
   痛点区
   ==================================================================== */
.pain-points {
    background: var(--color-bg-alt);
}

.pain-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.pain-card {
    padding: 40px 32px;
    border-radius: var(--radius-lg);
    background: var(--color-bg);
    border: 1px solid var(--color-border-light);
    text-align: center;
    transition: all var(--transition-base);
}

.pain-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-border);
}

.pain-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.pain-icon svg {
    width: 32px;
    height: 32px;
}

.pain-title {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 12px;
}

.pain-text {
    color: var(--color-text-secondary);
    font-size: .95rem;
}

/* ====================================================================
   方案区
   ==================================================================== */
.solution {
    background: var(--color-bg);
}

.solution-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-bottom: 48px;
}

.solution-card {
    padding: 40px 32px;
    border-radius: var(--radius-lg);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition-base);
}

.solution-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.solution-badge {
    display: inline-block;
    padding: 4px 14px;
    font-size: .8rem;
    font-weight: 700;
    border-radius: 999px;
    margin-bottom: 20px;
}

.solution-card:nth-child(1) .solution-badge {
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.solution-card:nth-child(2) .solution-badge {
    background: rgba(255,152,0,.12);
    color: var(--color-orange);
}

.solution-card:nth-child(3) .solution-badge {
    background: rgba(0,200,83,.12);
    color: var(--color-accent-dark);
}

.solution-title {
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 12px;
}

.solution-text {
    color: var(--color-text-secondary);
    font-size: .95rem;
    margin-bottom: 20px;
}

.solution-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.solution-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: .9rem;
    color: var(--color-text);
    font-weight: 500;
}

.solution-list li::before {
    content: "";
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--color-accent);
    flex-shrink: 0;
    position: relative;
}

.solution-list li::after {
    content: "";
    position: absolute;
    width: 5px;
    height: 8px;
    border-right: 2px solid #fff;
    border-bottom: 2px solid #fff;
    transform: rotate(45deg) translate(-2px, -1px);
    margin-left: 6.5px;
    margin-top: 3px;
}

/* AI 横幅 */
.ai-banner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    padding: 36px 40px;
    border-radius: var(--radius-lg);
    background: linear-gradient(135deg, var(--color-primary) 0%, #4a9af0 100%);
    color: #fff;
    flex-wrap: wrap;
}

.ai-banner-left {
    display: flex;
    align-items: center;
    gap: 24px;
    flex: 1;
    min-width: 300px;
}

.ai-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    background: rgba(255,255,255,.15);
    flex-shrink: 0;
}

.ai-icon svg {
    width: 32px;
    height: 32px;
    color: #fff;
}

.ai-title {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.ai-text {
    font-size: .95rem;
    opacity: .9;
}

.ai-banner .btn-accent {
    flex-shrink: 0;
}

/* ====================================================================
   差异化区
   ==================================================================== */
.differentiation {
    background: var(--color-bg-alt);
}

.diff-container {
    display: flex;
    align-items: stretch;
    gap: 24px;
    max-width: 1000px;
    margin: 0 auto;
}

.diff-col {
    flex: 1;
    padding: 36px 32px;
    border-radius: var(--radius-lg);
}

.diff-col-old {
    background: #fce4ec;
    border: 2px solid #f8bbd0;
}

.diff-col-new {
    background: #e8f5e9;
    border: 2px solid #c8e6c9;
}

.diff-col-header {
    text-align: center;
    margin-bottom: 28px;
}

.diff-tag {
    display: inline-block;
    padding: 4px 14px;
    font-size: .8rem;
    font-weight: 700;
    border-radius: 999px;
    margin-bottom: 12px;
}

.diff-tag-old {
    background: #ef5350;
    color: #fff;
}

.diff-tag-new {
    background: var(--color-accent);
    color: #fff;
}

.diff-col-header h3 {
    font-size: 1.4rem;
    font-weight: 700;
}

.diff-timeline {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.diff-step {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 14px 18px;
    border-radius: var(--radius-sm);
    background: rgba(255,255,255,.6);
    transition: all var(--transition-fast);
}

.diff-step-highlight-old {
    background: #ffcdd2;
    font-weight: 700;
}

.diff-step-highlight-new {
    background: #c8e6c9;
    font-weight: 700;
}

.diff-step-num {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--color-text);
    color: #fff;
    font-size: .85rem;
    font-weight: 700;
    flex-shrink: 0;
}

.diff-step-text {
    font-size: .95rem;
}

.diff-vs {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.diff-vs span {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-text-muted);
    background: #fff;
    border: 3px solid var(--color-border);
    border-radius: 50%;
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ====================================================================
   功能区
   ==================================================================== */
.features {
    background: var(--color-bg);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.feature-card {
    padding: 36px 28px;
    border-radius: var(--radius-lg);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    margin-bottom: 20px;
    color: #fff;
}

.feature-icon svg {
    width: 28px;
    height: 28px;
}

.feature-icon-blue   { background: var(--color-primary); }
.feature-icon-green  { background: var(--color-accent); }
.feature-icon-orange { background: var(--color-orange); }
.feature-icon-purple { background: var(--color-purple); }
.feature-icon-red    { background: var(--color-red); }
.feature-icon-teal   { background: var(--color-teal); }

.feature-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.feature-text {
    color: var(--color-text-secondary);
    font-size: .93rem;
}

/* ====================================================================
   定价区
   ==================================================================== */
.pricing {
    background: var(--color-bg-alt);
}

.pricing-grid {
    display: flex;
    gap: 32px;
    justify-content: center;
    flex-wrap: wrap;
}

.pricing-card {
    flex: 1;
    min-width: 340px;
    max-width: 420px;
    padding: 40px 36px;
    border-radius: var(--radius-lg);
    background: var(--color-bg);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition-base);
    position: relative;
}

.pricing-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.pricing-card-featured {
    border-color: var(--color-primary);
    border-width: 2px;
    box-shadow: var(--shadow-lg);
}

.pricing-badge {
    position: absolute;
    top: -14px;
    left: 50%;
    transform: translateX(-50%);
    padding: 6px 20px;
    background: var(--color-primary);
    color: #fff;
    font-size: .8rem;
    font-weight: 700;
    border-radius: 999px;
    white-space: nowrap;
}

.pricing-header {
    text-align: center;
    margin-bottom: 24px;
}

.pricing-name {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.pricing-price {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 2px;
}

.price-symbol {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--color-text);
}

.price-amount {
    font-size: 3rem;
    font-weight: 800;
    color: var(--color-text);
    line-height: 1;
}

.price-period {
    font-size: 1rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

.pricing-desc {
    text-align: center;
    color: var(--color-text-secondary);
    font-size: .9rem;
    margin-bottom: 24px;
}

.pricing-features {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 20px;
}

.pricing-features li {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: .93rem;
    color: var(--color-text);
}

.pricing-features-disabled li {
    color: var(--color-text-muted);
}

.check, .cross {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-size: .7rem;
    font-weight: 700;
}

.check {
    background: var(--color-accent);
    color: #fff;
}

.check::after {
    content: "";
    width: 5px;
    height: 9px;
    border-right: 2px solid #fff;
    border-bottom: 2px solid #fff;
    transform: rotate(45deg) translate(-1px, -1px);
}

.cross {
    background: #eee;
    color: #999;
}

.cross::after {
    content: "×";
    font-size: .9rem;
    line-height: 1;
}

.pricing-note {
    text-align: center;
    color: var(--color-text-muted);
    font-size: .9rem;
    margin-top: 32px;
}

/* ====================================================================
   FAQ 区
   ==================================================================== */
.faq {
    background: var(--color-bg);
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    border-radius: var(--radius-md);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border-light);
    overflow: hidden;
    transition: all var(--transition-fast);
}

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

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    background: none;
    border: none;
    cursor: pointer;
    font-family: inherit;
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--color-text);
    text-align: left;
}

.faq-icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
    position: relative;
    margin-left: 16px;
}

.faq-icon::before,
.faq-icon::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    background: var(--color-primary);
    border-radius: 2px;
    transition: all var(--transition-base);
}

.faq-icon::before {
    width: 14px;
    height: 2px;
    transform: translate(-50%, -50%);
}

.faq-icon::after {
    width: 2px;
    height: 14px;
    transform: translate(-50%, -50%);
}

.faq-item.active .faq-icon::after {
    transform: translate(-50%, -50%) rotate(90deg);
    opacity: 0;
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
}

.faq-answer p {
    padding: 0 24px 20px;
    color: var(--color-text-secondary);
    font-size: .95rem;
}

/* ====================================================================
   下载区
   ==================================================================== */
.download {
    background: var(--color-bg-alt);
}

.download-box {
    text-align: center;
    padding: 64px 40px;
    border-radius: var(--radius-xl);
    background: linear-gradient(135deg, var(--color-primary) 0%, #4a9af0 100%);
    color: #fff;
}

.download-title {
    font-size: clamp(1.5rem, 3.5vw, 2.2rem);
    font-weight: 800;
    margin-bottom: 12px;
}

.download-text {
    font-size: 1.05rem;
    opacity: .9;
    margin-bottom: 32px;
}

.download-cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.download-box .btn-outline {
    color: #fff;
    border-color: rgba(255,255,255,.5);
}

.download-box .btn-outline:hover {
    background: rgba(255,255,255,.15);
    border-color: #fff;
    transform: translateY(-2px);
}

.download-hint {
    font-size: .85rem;
    opacity: .7;
}

/* ====================================================================
   Footer
   ==================================================================== */
.footer {
    background: #1a1a2e;
    color: rgba(255,255,255,.7);
    padding: 64px 0 32px;
}

.footer-top {
    display: flex;
    justify-content: space-between;
    gap: 48px;
    flex-wrap: wrap;
    margin-bottom: 40px;
}

.footer-brand {
    max-width: 300px;
}

.footer-brand .nav-logo {
    color: #fff;
    margin-bottom: 12px;
}

.footer-tagline {
    font-size: .95rem;
    opacity: .7;
}

.footer-links {
    display: flex;
    gap: 64px;
    flex-wrap: wrap;
}

.footer-col h4 {
    color: #fff;
    font-size: .95rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.footer-col a {
    display: block;
    font-size: .9rem;
    opacity: .7;
    padding: 4px 0;
    transition: all var(--transition-fast);
}

.footer-col a:hover {
    opacity: 1;
    color: var(--color-primary-light);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    padding-top: 24px;
    border-top: 1px solid rgba(255,255,255,.1);
    font-size: .85rem;
    opacity: .6;
}

.footer-bottom a:hover {
    opacity: 1;
    color: var(--color-primary-light);
}

/* ====================================================================
   滚动动画
   ==================================================================== */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity .6s ease, transform .6s ease;
    transition-delay: var(--delay, 0s);
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ====================================================================
   响应式 — 平板
   ==================================================================== */
@media (max-width: 968px) {
    .pain-grid,
    .solution-grid,
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .diff-container {
        flex-direction: column;
    }

    .diff-vs {
        padding: 8px 0;
    }

    .diff-vs span {
        width: 48px;
        height: 48px;
        font-size: 1.2rem;
    }

    .ai-banner {
        flex-direction: column;
        text-align: center;
    }

    .ai-banner-left {
        flex-direction: column;
        text-align: center;
    }

    .footer-top {
        flex-direction: column;
        gap: 32px;
    }
}

/* ====================================================================
   响应式 — 手机
   ==================================================================== */
@media (max-width: 640px) {
    .section {
        padding: 64px 0;
    }

    .container,
    .container-narrow {
        padding: 0 20px;
    }

    /* 导航栏 */
    .nav-menu {
        position: fixed;
        top: 68px;
        left: 0;
        width: 100%;
        flex-direction: column;
        background: #fff;
        padding: 16px 20px;
        gap: 4px;
        box-shadow: var(--shadow-md);
        transform: translateY(-150%);
        transition: transform var(--transition-base);
        z-index: 999;
    }

    .nav-menu.active {
        transform: translateY(0);
    }

    .nav-link,
    .nav-cta {
        width: 100%;
        text-align: center;
        margin-left: 0;
    }

    .hamburger {
        display: flex;
    }

    /* Hero */
    .hero-stats {
        gap: 32px;
    }

    .stat-number {
        font-size: 1.5rem;
    }

    /* 痛点/方案/功能 */
    .pain-grid,
    .solution-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }

    .pain-card,
    .solution-card,
    .feature-card {
        padding: 32px 24px;
    }

    /* 定价 */
    .pricing-card {
        min-width: 100%;
    }

    .pricing-grid {
        gap: 24px;
    }

    /* FAQ */
    .faq-question {
        font-size: .95rem;
        padding: 18px 20px;
    }

    .faq-answer p {
        padding: 0 20px 18px;
        font-size: .9rem;
    }

    /* 下载区 */
    .download-box {
        padding: 48px 24px;
    }

    .download-cta {
        flex-direction: column;
    }

    .download-cta .btn {
        width: 100%;
    }

    /* Footer */
    .footer-links {
        gap: 32px;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

/* ====================================================================
   响应式 — 小屏
   ==================================================================== */
@media (max-width: 380px) {
    .hero-cta-group {
        flex-direction: column;
        width: 100%;
    }

    .hero-cta-group .btn {
        width: 100%;
    }
}