/* ============================================================
   隐患识别助手 · 营销首页 —— 与登录页同款配色（蓝 + 白）
   主色 #1677ff（#0958d9 深色变体）· 白卡片 · 移动优先响应式
   ============================================================ */

/* ---------- 设计 token ---------- */
:root {
    --bg-page: #F7F9FC;
    --bg-card: #fff;
    --bg-card-hover: #F0F7FF;
    --accent: #1677ff;
    --accent-strong: #0958d9;
    --accent-grad: linear-gradient(135deg, #1677ff 0%, #0958d9 100%);
    --text-primary: #1a1a1a;
    --text-secondary: #8c8c8c;
    --border: rgba(0, 0, 0, 0.08);
    --radius: 12px;
    --radius-lg: 16px;
    --max-width: 1100px;
}

/* ---------- 全局 reset 与基础 ---------- */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    background: var(--bg-page);
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

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

::selection {
    background: rgba(22, 119, 255, 0.2);
}

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* 区块统一节奏（移动端 64px，桌面 96px 见媒体查询） */
.pain-points,
.stats-section,
.features,
.workflow,
.faq,
.cta-final {
    padding: 64px 0;
}

/* ---------- 装饰条纹分隔 ---------- */
.section-divider {
    height: 6px;
    background: repeating-linear-gradient(-45deg, var(--accent) 0 14px, transparent 14px 28px);
    opacity: 0.3;
}

/* ============================================================
   吸顶导航
   ============================================================ */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.92);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--text-primary);
}

.nav-logo img {
    width: 30px;
    height: 30px;
    flex-shrink: 0;
    border-radius: 6px;
}

.logo-text {
    font-size: 17px;
    font-weight: 700;
    color: var(--text-primary);
    white-space: nowrap;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

/* 登录下拉（details/summary 原生开合） */
.nav-login {
    position: relative;
}

.nav-login summary {
    list-style: none;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-secondary);
    transition: color 0.2s ease;
    white-space: nowrap;
    padding: 8px 0;
}

.nav-login summary::-webkit-details-marker {
    display: none;
}

.nav-login summary:hover,
.nav-login[open] > summary {
    color: var(--accent);
}

.nav-login-menu {
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    min-width: 128px;
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    padding: 6px;
    z-index: 110;
}

.nav-login-menu a {
    display: block;
    padding: 10px 14px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    white-space: nowrap;
    border-radius: 4px;
    transition: background 0.2s ease, color 0.2s ease;
}

.nav-login-menu a:hover {
    background: rgba(22, 119, 255, 0.06);
    color: var(--accent);
}

/* ============================================================
   按钮体系
   ============================================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 16px;
    font-family: inherit;
    line-height: 1.2;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.btn-primary {
    background: #1677ff;
    color: #fff;
}

.btn-primary:hover {
    background: #4096ff;
    transform: translateY(-1px);
    box-shadow: 0 4px 20px rgba(22, 119, 255, 0.35);
}

.btn-primary:active {
    background: #0958d9;
    transform: translateY(0);
    box-shadow: none;
}

/* 次按钮仅在 Hero（蓝色渐变底）使用：白边白字 */
.btn-secondary {
    background: transparent;
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.4);
}

.btn-secondary:hover {
    border-color: rgba(255, 255, 255, 0.85);
    color: #fff;
}

.btn-sm {
    padding: 9px 20px;
    font-size: 14px;
}

.btn-cta {
    padding: 18px 48px;
    font-size: 18px;
}

/* ============================================================
   Hero 首屏（登录页同款蓝色渐变背景）
   ============================================================ */
.hero {
    position: relative;
    display: flex;
    align-items: center;
    min-height: 100vh;
    min-height: 100svh;
    padding: 96px 0 64px;
    background:
        radial-gradient(ellipse at 75% 12%, rgba(255, 255, 255, 0.14), transparent 50%),
        linear-gradient(135deg, #1677ff 0%, #0958d9 100%);
}

.hero-inner {
    display: flex;
    flex-direction: column;
    gap: 40px;
}

.hero-copy {
    flex: 1 1 55%;
}

.hero-eyebrow {
    display: flex;
    align-items: center;
    gap: 10px;
    color: rgba(255, 255, 255, 0.85);
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.12em;
}

.hero-eyebrow::before {
    content: "";
    width: 24px;
    height: 2px;
    background: #fff;
    flex-shrink: 0;
}

.hero-title {
    margin-top: 16px;
    font-size: clamp(2rem, 8vw, 3.5rem);
    font-weight: 700;
    line-height: 1.2;
    color: #fff;
}

.hero-subtitle {
    margin-top: 20px;
    color: rgba(255, 255, 255, 0.85);
    font-size: 16px;
    max-width: 34em;
}

.hero-actions {
    margin-top: 32px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.hero-actions .btn {
    width: 100%;
}

.hero-art {
    flex: 1 1 45%;
}

.hero-art svg {
    width: 100%;
    height: auto;
    max-width: 320px;
    margin: 0 auto;
    opacity: 0.95;
}

/* ============================================================
   区块标题
   ============================================================ */
.section-head {
    text-align: center;
    margin-bottom: 48px;
}

.eyebrow {
    color: var(--accent);
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
}

.section-title {
    margin-top: 12px;
    font-size: clamp(1.5rem, 5vw, 2.25rem);
    font-weight: 700;
    line-height: 1.3;
}

.section-sub {
    color: var(--text-secondary);
    margin-top: 12px;
}

/* ============================================================
   卡片（痛点 + 功能共用）
   ============================================================ */
.card-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
    padding: 28px;
    transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.card:hover {
    transform: translateY(-4px);
    border-color: rgba(22, 119, 255, 0.45);
    box-shadow: 0 8px 24px rgba(22, 119, 255, 0.1);
}

.card-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent);
    background: rgba(22, 119, 255, 0.08);
    border-radius: var(--radius);
    margin-bottom: 20px;
}

.card-icon svg {
    width: 24px;
    height: 24px;
}

.card-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 10px;
}

.card-desc {
    color: var(--text-secondary);
    font-size: 15px;
}

/* ============================================================
   使用流程
   ============================================================ */
.steps {
    list-style: none;
    display: grid;
    gap: 16px;
    position: relative;
    padding-left: 18px;
}

/* 移动端时间轴竖线 */
.steps::before {
    content: "";
    position: absolute;
    left: 0;
    top: 16px;
    bottom: 16px;
    width: 2px;
    background: linear-gradient(180deg, var(--accent), rgba(22, 119, 255, 0.15));
}

.step {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
    padding: 24px;
    transition: border-color 0.25s ease;
}

.step:hover {
    border-color: rgba(22, 119, 255, 0.35);
}

/* 步骤编号：右上角水印式大数字 */
.step-num {
    position: absolute;
    top: 14px;
    right: 16px;
    font-size: 40px;
    font-weight: 800;
    line-height: 1;
    letter-spacing: 0.02em;
    color: rgba(22, 119, 255, 0.15);
}

.step-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent);
    background: rgba(22, 119, 255, 0.08);
    border-radius: var(--radius);
}

.step-icon svg {
    width: 22px;
    height: 22px;
}

.step-title {
    margin-top: 16px;
    font-size: 17px;
    font-weight: 600;
}

.step-desc {
    margin-top: 8px;
    color: var(--text-secondary);
    font-size: 14px;
}

/* ============================================================
   FAQ 常见问题
   ============================================================ */
.faq-list {
    max-width: 760px;
    margin: 0 auto;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
    margin-bottom: 12px;
    transition: border-color 0.2s ease;
}

.faq-item[open] {
    border-color: rgba(22, 119, 255, 0.35);
}

.faq-item summary {
    cursor: pointer;
    padding: 16px 20px;
    font-weight: 600;
    font-size: 16px;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

/* + / - 图标（两条交叉线） */
.faq-icon {
    flex-shrink: 0;
    width: 22px;
    height: 22px;
    position: relative;
}

.faq-icon::before,
.faq-icon::after {
    content: "";
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    background: var(--accent);
    border-radius: 1px;
    transition: height 0.2s ease;
}

.faq-icon::before {
    width: 14px;
    height: 2px;
}

.faq-icon::after {
    width: 2px;
    height: 14px;
}

.faq-item[open] .faq-icon::after {
    height: 0;
}

.faq-answer {
    padding: 0 20px 20px;
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 15px;
}

/* ============================================================
   底部 CTA（蓝色渐变底 + 白字，与登录页呼应）
   ============================================================ */
.cta-final {
    position: relative;
    background: linear-gradient(135deg, #1677ff 0%, #0958d9 100%);
}

/* 装饰性白色半透明顶线 */
.cta-final::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: rgba(255, 255, 255, 0.25);
}

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

.cta-title {
    font-size: clamp(2rem, 5vw, 2.75rem);
    font-weight: 700;
    line-height: 1.25;
    color: #fff;
}

.cta-sub {
    margin-top: 16px;
    color: rgba(255, 255, 255, 0.85);
    font-size: 16px;
}

/* 蓝底上的主按钮反色：白底蓝字更醒目 */
.cta-final .btn-primary {
    background: #fff;
    color: #1677ff;
}

.cta-final .btn-primary:hover {
    background: #e6f4ff;
    box-shadow: 0 4px 20px rgba(255, 255, 255, 0.35);
}

.cta-final .btn-primary:active {
    background: #d6e9ff;
}

.btn-cta {
    margin: 32px 0;
}

.contact-card {
    max-width: 560px;
    margin: 40px auto 0;
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: var(--radius-lg);
    padding: 24px;
    color: rgba(255, 255, 255, 0.9);
    font-size: 14px;
    text-align: center;
}

.contact-note {
    margin: 0 0 18px;
}

.contact-grid {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 18px;
}

.contact-phone {
    display: flex;
    align-items: center;
    gap: 14px;
}

.contact-phone-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.16);
    color: #fff;
    flex-shrink: 0;
}

.contact-phone-icon svg {
    width: 22px;
    height: 22px;
}

.contact-phone-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
    text-align: left;
}

.contact-label {
    color: rgba(255, 255, 255, 0.75);
    font-size: 12px;
}

.contact-number {
    color: #fff;
    font-size: 22px;
    font-weight: 700;
    letter-spacing: 0.02em;
    white-space: nowrap;
    text-decoration: none;
}

.contact-number:hover {
    text-decoration: underline;
    text-underline-offset: 4px;
}

.contact-divider {
    width: 64px;
    height: 1px;
    background: rgba(255, 255, 255, 0.3);
}

.contact-qr {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.qr-codes {
    display: flex;
    gap: 10px;
}

.qr-img {
    width: 96px;
    height: 96px;
    padding: 5px;
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
    object-fit: contain;
}

/* ============================================================
   页脚
   ============================================================ */
.footer {
    border-top: 1px solid var(--border);
    padding: 32px 0;
    background: #fff;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px 24px;
}

.footer-links a {
    color: var(--text-secondary);
    font-size: 14px;
    text-decoration: none;
    transition: color 0.2s ease;
}

.footer-links a:hover {
    color: var(--accent);
}

.footer-copy {
    text-align: center;
    color: var(--text-secondary);
    font-size: 13px;
    margin-top: 16px;
}

/* ============================================================
   滚动动效配套（JS 就位后 .visible 触发）
   ============================================================ */
.reveal {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
    opacity: 1;
    transform: none;
}

/* ============================================================
   桌面断点（≥768px）
   ============================================================ */
@media (min-width: 768px) {
    .pain-points,
    .stats-section,
    .features,
    .workflow,
    .faq,
    .cta-final {
        padding: 96px 0;
    }

    /* Hero 两栏 */
    .hero {
        padding: 112px 0 96px;
    }

    .hero-inner {
        flex-direction: row;
        align-items: center;
        gap: 48px;
    }

    .hero-actions {
        flex-direction: row;
        gap: 16px;
    }

    .hero-actions .btn {
        width: auto;
    }

    .hero-art svg {
        max-width: none;
    }

    /* 卡片网格三列 */
    .card-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 24px;
    }

    /* 流程横向四列 + 步骤间连接线 */
    .steps {
        grid-template-columns: repeat(4, 1fr);
        gap: 24px;
        padding-left: 0;
    }

    .steps::before {
        display: none;
    }

    .step:not(:last-child)::after {
        content: "";
        position: absolute;
        top: 43px;
        left: calc(100% + 4px);
        width: 16px;
        height: 2px;
        background: linear-gradient(90deg, var(--accent), rgba(22, 119, 255, 0.15));
    }

    .step-num {
        font-size: 48px;
        top: 16px;
        right: 20px;
    }

    .faq-item summary {
        padding: 18px 24px;
    }

    .faq-answer {
        padding: 0 24px 20px;
    }

    /* 联系卡桌面横排：电话 | 竖线 | 二维码 */
    .contact-grid {
        flex-direction: row;
        gap: 28px;
    }

    .contact-divider {
        width: 1px;
        height: auto;
        align-self: stretch;
    }
}

/* ============================================================
   无障碍：减弱动效回退
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    .reveal {
        opacity: 1;
        transform: none;
        transition: none;
    }
}

/* ============================================================
   数据背书区块（预留，HTML 后续插入）
   ============================================================ */
.stats-section .stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.stats-section .stat-num {
    font-size: clamp(2rem, 6vw, 3rem);
    font-weight: 800;
    color: var(--accent);
    background: var(--accent-grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
}

.stats-section .stat-label {
    color: var(--text-secondary);
    margin-top: 8px;
}

@media (min-width: 768px) {
    .stats-section .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}