/* ===== 全局重置 & 基础 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 品牌色：淘宝橙（ChatUI 品牌主色） */
    --primary: #FF6200;
    --primary-dark: #D45A00;
    --secondary: #FFA040;
    --accent: #F59E0B;
    --success: #22C55E;
    /* 背景与文字：夜青黑 + 雾灰蓝（ChatUI 语义色） */
    --bg: #F3F6F8;
    --white: #FFFFFF;
    --text-dark: #11192D;
    --text-mid: #4A5675;
    --text-light: #8C9AB5;
    --radius: 12px;
    --radius-btn: 24px;
    /* 中性阴影：使用夜青黑色调，更克制内敛 */
    --shadow: 0 4px 24px rgba(17, 25, 45, 0.08);
    --shadow-lg: 0 12px 48px rgba(17, 25, 45, 0.12);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    scroll-behavior: smooth;
}

body {
    /* 字体遵循 ChatUI 规范：优先系统原生字体（中文 PingFang SC / 思源黑体） */
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text-dark);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    /* 小屏取 90% 两侧留白，大屏封顶 1280px 防止过宽（2K/4K 屏下阅读舒适） */
    max-width: min(90%, 1280px);
    margin: 0 auto;
    /* 内边距遵循 ChatUI 4px 基础单位 */
    padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 98, 0, 0.06);
    transition: var(--transition);
}

.navbar .container {
    max-width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 68px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
}

.nav-logo .logo-group {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 0px;
}

.nav-logo .logo-main {
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-logo .logo-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 18px;
    font-weight: 700;
    flex-shrink: 0;
}

.nav-logo .brand-name {
    font-weight: 800;
    font-size: 22px;
    color: var(--text-dark);
    letter-spacing: -0.5px;
    white-space: nowrap;
}

.nav-logo .brand-name .highlight {
    color: var(--primary);
}

.nav-logo .brand-sub {
    font-size: 11px;
    font-weight: 500;
    color: var(--text-light);
    letter-spacing: 0.3px;
    margin-left: 46px;
    padding-top: 1px;
    white-space: nowrap;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

.nav-actions a {
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: var(--radius-btn);
    transition: var(--transition);
}

.nav-actions .btn-login {
    color: var(--text-mid);
}

.nav-actions .btn-login:hover {
    color: var(--primary);
}

.nav-actions .btn-register {
    color: var(--text-mid);
}

.nav-actions .btn-register:hover {
    color: var(--primary);
}

/* ===== 已登录态导航 ===== */
.nav-actions .nav-user {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
    padding: 6px 12px;
    background: rgba(255, 98, 0, 0.06);
    border-radius: var(--radius-btn);
}

.nav-actions .btn-profile {
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-mid);
    padding: 8px 16px;
    border-radius: var(--radius-btn);
    transition: var(--transition);
}

.nav-actions .btn-profile:hover {
    color: var(--primary);
    background: rgba(255, 98, 0, 0.06);
}

.nav-actions .btn-synthesis {
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    color: white;
    padding: 8px 16px;
    border-radius: var(--radius-btn);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    box-shadow: 0 4px 16px rgba(255, 98, 0, 0.30);
    transition: var(--transition);
}

.nav-actions .btn-synthesis:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(255, 98, 0, 0.40);
}

.nav-actions .btn-nav-coming {
    text-decoration: none;
    font-size: 13px;
    font-weight: 500;
    color: var(--primary);
    padding: 8px 12px;
    border: 1px dashed rgba(255, 98, 0, 0.35);
    border-radius: var(--radius-btn);
    background: rgba(255, 98, 0, 0.04);
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.nav-actions .btn-nav-coming:hover {
    background: rgba(255, 98, 0, 0.10);
    border-color: var(--primary);
}

/* 默认高亮（听力合成） */
.nav-actions .btn-nav-coming.btn-highlight {
    color: white;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border: 1px solid transparent;
    box-shadow: 0 4px 16px rgba(255, 98, 0, 0.30);
}

.nav-actions .btn-nav-coming.btn-highlight:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(255, 98, 0, 0.40);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
}

.nav-actions .btn-logout {
    font-family: inherit;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-mid);
    background: transparent;
    border: 1px solid var(--border);
    padding: 8px 16px;
    border-radius: var(--radius-btn);
    cursor: pointer;
    transition: var(--transition);
}

.nav-actions .btn-logout:hover {
    color: var(--danger);
    border-color: var(--danger);
    background: rgba(239, 68, 68, 0.04);
}

/* 返回按钮（子页面导航栏使用） */
.nav-actions .nav-link {
    font-family: inherit;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-mid);
    text-decoration: none;
    padding: 8px 16px;
    border: none;
    background: transparent;
    border-radius: var(--radius-btn);
    cursor: pointer;
    transition: var(--transition);
}

.nav-actions .nav-link:hover {
    color: var(--primary);
    background: rgba(255, 98, 0, 0.06);
}

/* ===== Hero 区域 ===== */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(165deg, #FFF6EC 0%, #F3F6F8 60%, #FFFFFF 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -40%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255, 160, 64, 0.06) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(255, 98, 0, 0.05) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-content h1 {
    font-size: 52px;
    font-weight: 800;
    line-height: 1.12;
    letter-spacing: -1.5px;
    margin-bottom: 28px;
}

.hero-content h1 .gradient-text {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-content .subtitle {
    font-size: 18px;
    color: var(--text-mid);
    margin-bottom: 36px;
    max-width: 560px;
    line-height: 1.8;
}

.hero-content .subtitle .brand-tag {
    display: inline-block;
    background: rgba(255, 98, 0, 0.06);
    color: var(--primary);
    font-weight: 600;
    padding: 4px 12px;
    border-radius: 8px;
    font-size: 16px;
    margin-bottom: 8px;
}

.hero-content .subtitle .sub-desc {
    display: block;
    font-size: 15px;
    color: var(--text-mid);
    margin-top: 10px;
    line-height: 1.7;
}

/* ===== Hero 标签行（并排） ===== */
.hero-tags {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 24px;
}

.speed-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(245, 158, 11, 0.12);
    color: #D97706;
    padding: 4px 12px;
    border-radius: 9999px;
    font-size: 14px;
    font-weight: 600;
}

.speed-tag .dot-pulse {
    width: 6px;
    height: 6px;
    background: #D97706;
    border-radius: 50%;
    display: inline-block;
    animation: pulse-dot 1.5s ease-in-out infinite;
}

@keyframes pulse-dot {
    0%,
    100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.4;
        transform: scale(0.7);
    }
}

.free-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(34, 197, 94, 0.10);
    color: #16A34A;
    padding: 4px 12px;
    border-radius: 9999px;
    font-size: 14px;
    font-weight: 600;
    border: 1px solid rgba(34, 197, 94, 0.15);
}

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

.hero-actions .btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 40px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    border-radius: var(--radius-btn);
    transition: var(--transition);
    box-shadow: 0 4px 20px rgba(255, 98, 0, 0.30);
}

.hero-actions .btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(255, 98, 0, 0.40);
}

.hero-actions .btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 32px;
    background: var(--white);
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    border-radius: var(--radius-btn);
    border: 1.5px solid #E2E8F0;
    transition: var(--transition);
}

.hero-actions .btn-secondary:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-2px);
}

/* 试听合成效果按钮 */
.hero-actions .btn-trial {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 32px;
    background: var(--white);
    color: var(--text-dark);
    font-weight: 600;
    font-size: 16px;
    border-radius: var(--radius-btn);
    border: 1.5px solid #E2E8F0;
    cursor: pointer;
    font-family: inherit;
    transition: var(--transition);
}

.hero-actions .btn-trial:hover {
    border-color: #67C23A;
    color: #67C23A;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(103, 194, 58, 0.18);
}

.hero-actions .btn-trial.playing {
    background: linear-gradient(135deg, #67C23A, #95D475);
    border-color: transparent;
    color: #fff;
    box-shadow: 0 4px 20px rgba(103, 194, 58, 0.35);
}

.hero-actions .btn-trial .trial-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: #67C23A;
    color: #fff;
    font-size: 12px;
    font-weight: 700;
    transition: var(--transition);
}

.hero-actions .btn-trial:hover .trial-icon {
    background: #fff;
    color: #67C23A;
}

.hero-actions .btn-trial.playing .trial-icon {
    background: #fff;
    color: #67C23A;
}

.hero-stats {
    display: flex;
    gap: 48px;
    margin-top: 40px;
    padding-top: 32px;
    border-top: 1px solid #E2E8F0;
    align-items: flex-start;
}

.hero-stats .stat-item {
    display: flex;
    flex-direction: column;
}

.hero-stats .stat-item .stat-number {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.2;
}

.hero-stats .stat-item .stat-number .highlight-num {
    color: var(--accent);
    font-size: 28px;
}

.hero-stats .stat-item .stat-label {
    font-size: 14px;
    color: var(--text-light);
}

.hero-stats .stat-item .stat-sub {
    font-size: 12px;
    color: var(--text-light);
    display: block;
    margin-top: 2px;
}

/* ===== 右侧声波视觉 ===== */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    min-height: 320px;
}

.wave-wrapper {
    position: relative;
    width: 100%;
    max-width: 480px;
}

.wave-container {
    position: relative;
    width: 100%;
    padding-bottom: 100%;
    background: linear-gradient(135deg, rgba(255, 98, 0, 0.04), rgba(255, 160, 64, 0.06));
    border-radius: 50%;
    overflow: visible;
}

.wave-container svg {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 72%;
    height: 72%;
    display: block;
    z-index: 3;
    pointer-events: none;
}

.float-badge {
    position: absolute;
    background: var(--white);
    padding: 6px 12px;
    border-radius: 9999px;
    box-shadow: var(--shadow);
    font-size: 11px;
    font-weight: 600;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 4px;
    animation: float 3.5s ease-in-out infinite;
    white-space: nowrap;
    z-index: 2;
    letter-spacing: 0.2px;
    border: 1px solid rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    max-width: 85%;
}

.float-badge .dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: #22C55E;
    display: inline-block;
    flex-shrink: 0;
}

.float-badge:nth-of-type(1) {
    top: 4%;
    right: 4%;
    animation-delay: 0s;
}

.float-badge:nth-of-type(2) {
    bottom: 10%;
    right: 4%;
    animation-delay: 0.6s;
    background: linear-gradient(135deg, #FFF4E6, #FFE8CC);
    color: #D45A00;
    font-size: 12px;
    padding: 6px 12px;
    border-color: rgba(255, 255, 255, 0.3);
}

.float-badge:nth-of-type(3) {
    bottom: 10%;
    left: 4%;
    animation-delay: 1.2s;
}

@keyframes float {
    0%,
    100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-5px);
    }
}

/* ===== 通用标题区 ===== */
.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-header .label {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    color: var(--primary);
    background: rgba(255, 98, 0, 0.08);
    padding: 4px 16px;
    border-radius: 9999px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    margin-bottom: 12px;
}

.section-header h2 {
    font-size: 38px;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 12px;
}

.section-header p {
    font-size: 18px;
    color: var(--text-mid);
    max-width: 600px;
    margin: 0 auto;
}

/* ===== 痛点/场景 ===== */
.pain-points {
    padding: 80px 0;
    background: var(--white);
}

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

.pain-card {
    background: var(--bg);
    padding: 36px 28px;
    border-radius: var(--radius);
    transition: var(--transition);
    border: 1px solid transparent;
}

.pain-card:hover {
    border-color: rgba(255, 98, 0, 0.12);
    box-shadow: var(--shadow);
    transform: translateY(-4px);
}

.pain-card .icon {
    font-size: 36px;
    margin-bottom: 16px;
    display: block;
}

.pain-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 8px;
}

.pain-card p {
    font-size: 15px;
    color: var(--text-mid);
    line-height: 1.8;
}

.pain-card .highlight-text {
    color: var(--primary);
    font-weight: 700;
}

.pain-card .highlight-orange {
    color: var(--accent);
    font-weight: 700;
    font-size: 18px;
}

/* ===== 核心功能（4列，卡片高度统一） ===== */
.features {
    padding: 80px 0;
    background: var(--bg);
}

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

.feature-card {
    background: var(--white);
    padding: 32px 20px;
    border-radius: var(--radius);
    text-align: center;
    transition: var(--transition);
    border: 1px solid #F1F5F9;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 280px;
}

.feature-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
    border-color: rgba(255, 98, 0, 0.10);
}

.feature-card .icon {
    font-size: 40px;
    margin-bottom: 14px;
    display: block;
}

.feature-card h4 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 6px;
}

.feature-card p {
    font-size: 14px;
    color: var(--text-mid);
    line-height: 1.6;
    margin-bottom: 10px;
    max-width: 95%;
}

.feature-card .feature-tag {
    display: inline-block;
    background: rgba(255, 98, 0, 0.08);
    color: var(--primary);
    font-weight: 600;
    font-size: 12px;
    padding: 4px 12px;
    border-radius: 9999px;
    letter-spacing: 0.2px;
    margin-top: 4px;
}

.feature-card .feature-tag-secondary {
    display: inline-block;
    background: rgba(255, 98, 0, 0.05);
    color: var(--text-mid);
    font-weight: 500;
    font-size: 12px;
    padding: 4px 12px;
    border-radius: 9999px;
    letter-spacing: 0.2px;
    margin-top: 4px;
}

.feature-card .time-badge {
    display: inline-block;
    margin-top: 6px;
    background: rgba(245, 158, 11, 0.10);
    color: #D97706;
    font-weight: 700;
    font-size: 15px;
    padding: 4px 16px;
    border-radius: 9999px;
}

/* ===== AI出题功能卡片 ===== */
.feature-card.feature-exam {
    border-color: rgba(34, 197, 94, 0.30);
    background: linear-gradient(135deg, #F0FDF4, #FFFFFF);
    position: relative;
    overflow: hidden;
}

.feature-card.feature-exam::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--success), #16A34A);
}

.feature-card.feature-exam:hover {
    border-color: var(--success);
    box-shadow: 0 4px 24px rgba(34, 197, 94, 0.18);
}

.feature-card .free-tag {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    margin-top: 6px;
    background: linear-gradient(135deg, var(--success), #16A34A);
    color: white;
    font-weight: 700;
    font-size: 12px;
    padding: 4px 16px;
    border-radius: 9999px;
    letter-spacing: 0.3px;
    box-shadow: 0 2px 12px rgba(34, 197, 94, 0.30);
}

.feature-card .exam-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin-top: 6px;
    background: rgba(255, 98, 0, 0.08);
    color: var(--primary);
    font-weight: 600;
    font-size: 12px;
    padding: 4px 16px;
    border-radius: 9999px;
    border: 1px solid rgba(255, 98, 0, 0.12);
}

.feature-card .exam-badge .check {
    color: var(--success);
    font-weight: 700;
}

/* ===== 用户证言 ===== */
.testimonials {
    padding: 80px 0;
    background: var(--white);
}

.testimonial-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.testimonial-card {
    background: var(--bg);
    padding: 32px 32px 28px;
    border-radius: var(--radius);
    border-left: 4px solid var(--primary);
    transition: var(--transition);
}

.testimonial-card:hover {
    box-shadow: var(--shadow);
}

.testimonial-card .quote {
    font-size: 15px;
    color: var(--text-mid);
    line-height: 1.8;
    font-style: italic;
}

.testimonial-card .quote .highlight-exam {
    color: var(--primary);
    font-weight: 700;
    font-style: normal;
}

.testimonial-card .author {
    margin-top: 16px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.testimonial-card .author .avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 16px;
    flex-shrink: 0;
}

.testimonial-card .author .info .name {
    font-weight: 700;
    font-size: 15px;
    color: var(--text-dark);
}

.testimonial-card .author .info .title {
    font-size: 13px;
    color: var(--text-light);
}

/* ===== 星级评分 ===== */
.testimonial-card .star-rating {
    font-size: 14px;
    margin-bottom: 12px;
    letter-spacing: 2px;
}

/* ===== FAQ 手风琴 ===== */
.faq {
    padding: 80px 0;
    background: var(--white);
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--bg);
    border-radius: var(--radius);
    border: 1px solid transparent;
    transition: var(--transition);
    overflow: hidden;
}

.faq-item:hover {
    border-color: rgba(255, 98, 0, 0.10);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 24px;
    background: none;
    border: none;
    cursor: pointer;
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
    text-align: left;
    gap: 16px;
    transition: var(--transition);
}

.faq-question:hover {
    color: var(--primary);
}

.faq-icon {
    font-size: 20px;
    font-weight: 300;
    color: var(--primary);
    flex-shrink: 0;
    transition: transform 0.3s ease;
    width: 24px;
    text-align: center;
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease, padding 0.35s ease;
    padding: 0 24px;
}

.faq-item.active .faq-answer {
    max-height: 200px;
    padding: 0 24px 18px;
}

.faq-answer p {
    font-size: 14px;
    color: var(--text-mid);
    line-height: 1.8;
}

/* ===== 导航栏 NEW 角标（仅听力合成按钮）===== */
.nav-actions .btn-nav-coming.has-new-badge {
    position: relative;
}

.nav-actions .btn-nav-coming.has-new-badge::after {
    content: 'NEW';
    position: absolute;
    top: -6px;
    right: -8px;
    background: linear-gradient(135deg, #EF4444, #DC2626);
    color: white;
    font-size: 9px;
    font-weight: 700;
    padding: 2px 4px;
    border-radius: var(--radius-sm);
    letter-spacing: 0.5px;
    line-height: 1.3;
}

/* ===== 使用流程 ===== */
.how-it-works {
    padding: 80px 0;
    background: var(--bg);
}

.steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    position: relative;
}

.steps::before {
    content: '';
    position: absolute;
    top: 40px;
    left: 16.6%;
    right: 16.6%;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--secondary), var(--primary));
    opacity: 0.2;
}

.step {
    text-align: center;
    position: relative;
}

.step .step-number {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    font-size: 22px;
    font-weight: 700;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    position: relative;
    z-index: 1;
}

.step h4 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 8px;
}

.step p {
    font-size: 14px;
    color: var(--text-mid);
    max-width: 260px;
    margin: 0 auto;
    line-height: 1.8;
}

.step .step-highlight {
    display: inline-block;
    background: rgba(255, 98, 0, 0.08);
    color: var(--primary);
    font-weight: 700;
    padding: 2px 12px;
    border-radius: 9999px;
    font-size: 15px;
    margin-top: 4px;
}

.step .step-free-tag {
    display: inline-block;
    margin-top: 6px;
    background: rgba(34, 197, 94, 0.12);
    color: #16A34A;
    font-weight: 700;
    font-size: 13px;
    padding: 2px 12px;
    border-radius: 9999px;
}

/* ===== 免费权益横幅 ===== */
.free-banner {
    background: linear-gradient(135deg, #22C55E, #16A34A);
    padding: 28px 0;
    color: white;
}

.free-banner .container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
    text-align: center;
}

.free-banner .icon-big {
    font-size: 32px;
}

.free-banner .main-text {
    font-size: 20px;
    font-weight: 700;
}

.free-banner .main-text .highlight-white {
    background: rgba(255, 255, 255, 0.20);
    padding: 2px 16px;
    border-radius: 9999px;
}

.free-banner .sub-text {
    font-size: 15px;
    opacity: 0.90;
}

/* ===== 套餐（捐赠） ===== */
.pricing {
    padding: 60px 0 40px;
    background: var(--bg);
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 24px;
}

/* 5张卡片：上排3张 + 下排2张居中（每张卡占2列） */
.pricing-grid > .pricing-card {
    grid-column: span 2;
}

.pricing-grid > .pricing-card:nth-child(4) {
    grid-column: 2 / span 2;
}

.pricing-grid > .pricing-card:nth-child(5) {
    grid-column: 4 / span 2;
}

.pricing-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 36px 24px;
    text-align: center;
    transition: var(--transition);
    border: 1px solid #F1F5F9;
    position: relative;
    display: flex;
    flex-direction: column;
}

.pricing-card .plan-icon {
    font-size: 36px;
    margin-bottom: 12px;
    line-height: 1;
}

.pricing-card.pricing-feature {
    border: 2px solid var(--primary);
    box-shadow: var(--shadow-lg);
}

.pricing-card.pricing-free {
    border: 2px solid rgba(34, 197, 94, 0.35);
    background: linear-gradient(180deg, rgba(34, 197, 94, 0.04) 0%, var(--white) 100%);
}

.pricing-card.pricing-free .price {
    color: #16A34A;
}

.pricing-card .price .price-unit {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-mid);
    margin-left: 2px;
}

.pricing-card .btn-plan-free {
    background: linear-gradient(135deg, #22C55E, #16A34A);
    color: white;
    box-shadow: 0 4px 20px rgba(34, 197, 94, 0.25);
}

.pricing-card .btn-plan-free:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(34, 197, 94, 0.35);
}

/* ===== 语音合成 双模式卡片（免费 + 付费）===== */
.pricing-card.pricing-dual {
    border: 1px solid #F1F5F9;
}

.pricing-card .dual-price {
    margin-bottom: 16px;
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid #F1F5F9;
}

.pricing-card .dual-price-item {
    padding: 12px 8px;
    background: #FAFBFF;
    text-align: center;
}

.pricing-card .dual-price-item + .dual-price-item {
    border-top: 1px solid #E2E8F0;
}

.pricing-card .dual-divider {
    display: none;
}

.pricing-card .dual-tag {
    display: inline-block;
    font-size: 11px;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 9999px;
    margin-bottom: 6px;
    letter-spacing: 0.5px;
}

.pricing-card .dual-tag.free {
    background: rgba(34, 197, 94, 0.12);
    color: #16A34A;
}

.pricing-card .dual-tag.paid {
    background: rgba(255, 98, 0, 0.10);
    color: var(--primary);
}

.pricing-card .dual-amount {
    display: block;
    font-size: 20px;
    font-weight: 800;
    color: var(--text-dark);
    line-height: 1.2;
    margin-bottom: 4px;
}

.pricing-card .dual-amount .price-unit {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-mid);
    margin-left: 2px;
}

.pricing-card .dual-desc {
    display: block;
    font-size: 12px;
    color: var(--text-light);
    line-height: 1.5;
}

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

.pricing-card.popular {
    border: 2px solid var(--primary);
    box-shadow: var(--shadow-lg);
}

.pricing-card.popular .badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary);
    color: white;
    font-size: 12px;
    font-weight: 600;
    padding: 4px 20px;
    border-radius: 9999px;
    letter-spacing: 0.5px;
}

.pricing-card .plan-name {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 4px;
}

.pricing-card .plan-desc {
    font-size: 14px;
    color: var(--text-light);
    margin-bottom: 16px;
}

.pricing-card .price {
    font-size: 42px;
    font-weight: 800;
    color: var(--text-dark);
    margin-bottom: 4px;
}

.pricing-card .plan-credits {
    font-size: 15px;
    color: var(--text-mid);
    margin-bottom: 24px;
}

.pricing-card .plan-credits strong {
    color: var(--text-dark);
    font-size: 20px;
}

.pricing-card .btn-plan {
    display: inline-block;
    padding: 12px 48px;
    border-radius: var(--radius-btn);
    text-decoration: none;
    font-weight: 600;
    font-size: 15px;
    transition: var(--transition);
    width: 100%;
    margin-top: auto;
}

.pricing-card .btn-plan-outline {
    background: transparent;
    color: var(--primary);
    border: 1.5px solid var(--primary);
}

.pricing-card .btn-plan-outline:hover {
    background: var(--primary);
    color: white;
}

.pricing-card .btn-plan-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    box-shadow: 0 4px 20px rgba(255, 98, 0, 0.25);
}

.pricing-card .btn-plan-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(255, 98, 0, 0.35);
}

.pricing-card ul {
    list-style: none;
    margin-top: 20px;
    text-align: left;
    padding: 0;
}

.pricing-card ul li {
    font-size: 14px;
    color: var(--text-mid);
    padding: 6px 0;
    display: flex;
    align-items: center;
    gap: 8px;
}

.pricing-card ul li::before {
    content: '✓';
    color: var(--primary);
    font-weight: 700;
}

.pricing-card ul li .free-badge {
    display: inline-block;
    background: rgba(34, 197, 94, 0.12);
    color: #16A34A;
    font-size: 11px;
    font-weight: 700;
    padding: 0 12px;
    border-radius: 9999px;
    margin-left: 4px;
}

.pricing-card ul li .exam-format-badge {
    display: inline-block;
    background: rgba(255, 98, 0, 0.08);
    color: var(--primary);
    font-size: 10px;
    font-weight: 600;
    padding: 0 12px;
    border-radius: 9999px;
    margin-left: 4px;
    letter-spacing: 0.3px;
}

.pricing-footnote {
    text-align: center;
    margin-top: 32px;
    font-size: 14px;
    color: var(--text-light);
    line-height: 1.8;
}

.pricing-footnote .donate-note {
    display: inline-block;
    background: rgba(255, 98, 0, 0.06);
    color: var(--text-mid);
    padding: 6px 20px;
    border-radius: 9999px;
    font-size: 13px;
    font-weight: 500;
}

/* ===== 平台费用说明 ===== */
.cost-disclosure {
    padding: 40px 0 60px;
    background: var(--bg);
    border-top: 1px solid #E2E8F0;
}

/* .cost-disclosure .container 不再单独覆写 max-width，
   统一使用全局 .container 的 max-width: 90% */

.cost-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 36px 44px;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--accent);
}

.cost-card .cost-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.cost-card .cost-header .icon {
    font-size: 28px;
}

.cost-card .cost-header h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-dark);
}

.cost-card .cost-header .tag {
    font-size: 12px;
    font-weight: 600;
    color: var(--accent);
    background: rgba(245, 158, 11, 0.10);
    padding: 2px 12px;
    border-radius: 9999px;
    margin-left: auto;
}

.cost-card .cost-body {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.cost-card .cost-body .item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    font-size: 15px;
    color: var(--text-mid);
    line-height: 1.7;
    padding: 8px 16px;
    background: var(--bg);
    border-radius: 8px;
}

.cost-card .cost-body .item .emoji {
    flex-shrink: 0;
    font-size: 18px;
    margin-top: 2px;
}

.cost-card .cost-body .item strong {
    color: var(--text-dark);
}

.cost-card .cost-body .item .highlight-cost {
    color: var(--accent);
    font-weight: 700;
}

.cost-card .cost-footer {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid #F1F5F9;
    font-size: 14px;
    color: var(--text-light);
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.cost-card .cost-footer .heart {
    color: #EF4444;
}

/* ===== 速度对比横幅 ===== */
.speed-banner {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    padding: 40px 0;
    color: white;
}

.speed-banner .container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 64px;
    flex-wrap: wrap;
}

.speed-banner .compare-item {
    text-align: center;
}

.speed-banner .compare-item .number {
    font-size: 42px;
    font-weight: 800;
}

.speed-banner .compare-item .number .small-num {
    font-size: 20px;
    font-weight: 400;
    opacity: 0.8;
}

.speed-banner .compare-item .label {
    font-size: 15px;
    opacity: 0.85;
    margin-top: 10px;
}

.speed-banner .vs-divider {
    font-size: 24px;
    font-weight: 700;
    opacity: 0.5;
    letter-spacing: 2px;
}

.speed-banner .result-highlight {
    text-align: center;
}

.speed-banner .result-highlight .big-number {
    font-size: 52px;
    font-weight: 800;
    color: #FFFFFF;
}

.speed-banner .result-highlight .desc {
    font-size: 16px;
    opacity: 0.9;
    margin-top: 10px;
}

/* ===== 底部 ===== */
.footer {
    background: var(--text-dark);
    color: rgba(255, 255, 255, 0.7);
    padding: 48px 0 32px;
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
}

.footer .brand-group {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
}

.footer .brand {
    font-weight: 700;
    font-size: 18px;
    color: white;
}

.footer .brand .highlight {
    color: var(--primary);
}

.footer .brand-sub {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.4);
    letter-spacing: 0.3px;
}

.footer .links {
    display: flex;
    gap: 24px;
    font-size: 14px;
    flex-wrap: wrap;
}

.footer .links a {
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    transition: var(--transition);
}

.footer .links a:hover {
    color: white;
}

.footer .copyright {
    font-size: 13px;
    width: 100%;
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.06);
    margin-top: 16px;
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }
    .hero-content .subtitle {
        margin-left: auto;
        margin-right: auto;
    }
    .hero-actions {
        justify-content: center;
    }
    .hero-stats {
        justify-content: center;
    }
    .hero-tags {
        justify-content: center;
    }
    .hero-visual {
        min-height: 280px;
    }
    .wave-wrapper {
        max-width: 400px;
        margin: 0 auto;
    }
    .float-badge {
        font-size: 10px;
        padding: 4px 8px;
    }
    .float-badge:nth-of-type(2) {
        font-size: 11px;
        padding: 4px 12px;
    }
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .feature-card {
        min-height: 240px;
    }
    .pricing-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    /* 重置桌面端5卡居中定位，恢复普通流式排列 */
    .pricing-grid > .pricing-card,
    .pricing-grid > .pricing-card:nth-child(4),
    .pricing-grid > .pricing-card:nth-child(5) {
        grid-column: auto;
    }
    .steps::before {
        display: none;
    }
    .speed-banner .container {
        gap: 24px;
    }
    .speed-banner .result-highlight .big-number {
        font-size: 36px;
    }
    .testimonial-grid {
        grid-template-columns: 1fr;
    }
    .cost-card {
        padding: 28px 24px;
    }
    .cost-card .cost-body .item {
        font-size: 14px;
    }
}

@media (max-width: 768px) {
    .hero {
        padding: 120px 0 60px;
    }
    .hero-content h1 {
        font-size: 34px;
    }
    .hero-content .subtitle {
        font-size: 17px;
    }
    .hero-content .subtitle .brand-tag {
        font-size: 16px;
    }
    .hero-content .subtitle .sub-desc {
        font-size: 14px;
    }
    .hero-tags {
        gap: 8px;
        justify-content: center;
    }
    .speed-tag,
    .free-tag {
        font-size: 12px;
        padding: 4px 12px;
    }
    .hero-stats {
        flex-direction: column;
        gap: 16px;
        align-items: center;
    }
    .hero-visual {
        min-height: 220px;
    }
    .wave-wrapper {
        max-width: 280px;
    }
    .float-badge:nth-of-type(1) {
        display: none;
    }
    .float-badge:nth-of-type(2) {
        display: flex;
        top: auto;
        bottom: 6%;
        right: 6%;
        font-size: 11px;
        padding: 4px 12px;
        animation: none;
    }
    .float-badge:nth-of-type(3) {
        display: none;
    }
    .pain-grid {
        grid-template-columns: 1fr;
    }
    .features-grid {
        grid-template-columns: 1fr;
    }
    .feature-card {
        min-height: auto;
        padding: 28px 20px;
    }
    .steps {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .pricing-grid {
        grid-template-columns: 1fr;
        max-width: 400px;
    }
    .section-header h2 {
        font-size: 28px;
    }
    .nav-actions a {
        font-size: 13px;
        padding: 6px 12px;
    }
    .nav-logo .brand-sub {
        font-size: 10px;
        margin-left: 46px;
        white-space: normal;
    }
    .footer .container {
        flex-direction: column;
        text-align: center;
    }
    .footer .brand-group {
        align-items: center;
    }
    .footer .links {
        justify-content: center;
    }
    .speed-banner .container {
        flex-direction: column;
        gap: 16px;
    }
    .speed-banner .compare-item .number {
        font-size: 28px;
    }
    .speed-banner .result-highlight .big-number {
        font-size: 32px;
    }
    .speed-banner .vs-divider {
        font-size: 18px;
    }
    .free-banner .main-text {
        font-size: 17px;
    }
    .free-banner .sub-text {
        font-size: 13px;
    }
    .testimonial-grid {
        max-width: 100%;
    }
    .cost-card {
        padding: 24px 16px;
    }
    .cost-card .cost-header {
        flex-wrap: wrap;
    }
    .cost-card .cost-header .tag {
        margin-left: 0;
    }
    .cost-card .cost-body .item {
        font-size: 13px;
        padding: 8px 12px;
    }
    .cost-card .cost-footer {
        font-size: 13px;
    }
    .pricing-footnote .donate-note {
        font-size: 12px;
        padding: 4px 12px;
    }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 28px;
    }
    .hero-content .subtitle .brand-tag {
        font-size: 14px;
    }
    .hero-content .subtitle .sub-desc {
        font-size: 13px;
    }
    .hero-tags {
        gap: 6px;
    }
    .speed-tag,
    .free-tag {
        font-size: 11px;
        padding: 2px 8px;
    }
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    .hero-actions .btn-primary,
    .hero-actions .btn-secondary {
        width: 100%;
        justify-content: center;
    }
    .hero-visual {
        min-height: 180px;
    }
    .wave-wrapper {
        max-width: 200px;
    }
    .float-badge:nth-of-type(2) {
        font-size: 10px;
        padding: 4px 8px;
        bottom: 4%;
        right: 4%;
    }
    .pricing-card {
        padding: 28px 20px;
    }
    .hero-stats .stat-item .stat-number {
        font-size: 22px;
    }
    .nav-logo .brand-sub {
        font-size: 9px;
        margin-left: 0;
    }
    .nav-logo .logo-main .brand-name {
        font-size: 18px;
    }
    .nav-logo .logo-icon {
        width: 30px;
        height: 30px;
        font-size: 14px;
    }
    .free-banner .main-text {
        font-size: 15px;
    }
    .free-banner .sub-text {
        font-size: 12px;
    }
    .cost-card .cost-body .item {
        font-size: 12px;
        padding: 6px 8px;
    }
    .cost-card .cost-footer {
        font-size: 12px;
    }
    .pricing-footnote .donate-note {
        font-size: 11px;
        padding: 4px 12px;
    }
}