/* ============================================================
   爆款实验室 - 主样式表
   CSS前缀: bk-
   设计风格: 科学实验室风 (Science Lab Style)
   ============================================================ */

/* --- 干扰标签隐藏 --- */
.viral-jammer-block { display: none; }

/* --- CSS Reset & Base --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bk-white: #FFFFFF;
    --bk-light-gray: #F0F4F8;
    --bk-blue: #3366FF;
    --bk-blue-hover: #2952cc;
    --bk-text: #0A1F44;
    --bk-red: #FF4D4F;
    --bk-border: #E2E8F0;
    --bk-shadow: 0 4px 24px rgba(10, 31, 68, 0.08);
    --bk-shadow-hover: 0 8px 32px rgba(10, 31, 68, 0.14);
    --bk-radius: 8px;
    --bk-transition: 0.3s ease;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: "Roboto", "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--bk-text);
    background-color: var(--bk-white);
    line-height: 1.75;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
    font-weight: 700;
    line-height: 1.3;
}

a {
    color: var(--bk-blue);
    text-decoration: none;
    transition: color var(--bk-transition);
}

a:hover {
    color: var(--bk-blue-hover);
}

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

/* --- 容器 --- */
.bk-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* --- 导航栏 --- */
.bk-header {
    width: 100%;
    background: var(--bk-white);
    border-bottom: 1px solid var(--bk-border);
    z-index: 100;
    padding: 0;
}

.bk-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 68px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

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

.bk-logo-img {
    width: 36px;
    height: 36px;
    border-radius: 6px;
}

.sp-logo-text {
    font-family: "Helvetica Neue", Arial, sans-serif;
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--bk-text);
    letter-spacing: -0.02em;
}

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

.bk-nav-links a {
    position: relative;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--bk-text);
    padding: 6px 0;
    transition: color var(--bk-transition);
}

.bk-nav-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--bk-blue);
    transition: width var(--bk-transition);
}

.bk-nav-links a:hover {
    color: var(--bk-blue);
}

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

/* 汉堡菜单 */
.bk-hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
    background: none;
    border: none;
}

.bk-hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--bk-text);
    transition: all var(--bk-transition);
}

.bk-mobile-menu {
    display: none;
    position: fixed;
    top: 0;
    right: -280px;
    width: 280px;
    height: 100vh;
    background: var(--bk-white);
    box-shadow: -4px 0 24px rgba(0,0,0,0.1);
    z-index: 1000;
    transition: right var(--bk-transition);
    padding: 80px 30px 30px;
}

.bk-mobile-menu.bk-active {
    right: 0;
}

.bk-mobile-menu a {
    display: block;
    padding: 14px 0;
    font-size: 1.05rem;
    color: var(--bk-text);
    border-bottom: 1px solid var(--bk-border);
}

.bk-mobile-menu a:hover {
    color: var(--bk-blue);
}

.bk-mobile-close {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 1.5rem;
    cursor: pointer;
    background: none;
    border: none;
    color: var(--bk-text);
    padding: 8px;
}

.bk-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.3);
    z-index: 999;
}

.bk-overlay.bk-active {
    display: block;
}

/* --- 通用模块 --- */
.bk-section {
    padding: 80px 0;
}

.bk-section-alt {
    padding: 80px 0;
    background: var(--bk-light-gray);
}

.bk-section-title {
    font-size: 1.75rem;
    margin-bottom: 12px;
    color: var(--bk-text);
}

.bk-section-subtitle {
    font-size: 1rem;
    color: #64748B;
    margin-bottom: 40px;
    max-width: 680px;
}

.bk-section-label {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--bk-blue);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 8px;
    font-family: "Roboto Mono", monospace;
}

/* --- Hero / 爆款公式 --- */
.bk-hero {
    background: var(--bk-light-gray);
    background-image:
        linear-gradient(rgba(51,102,255,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(51,102,255,0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    padding: 100px 0 80px;
    position: relative;
    overflow: hidden;
}

.bk-hero-inner {
    display: flex;
    align-items: center;
    gap: 48px;
}

.bk-hero-content {
    flex: 1;
}

.bk-hero-content h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    line-height: 1.2;
}

.bk-hero-formula {
    font-family: "Roboto Mono", "Courier New", monospace;
    font-size: 1.1rem;
    background: var(--bk-white);
    border: 1px solid var(--bk-border);
    border-radius: var(--bk-radius);
    padding: 20px 24px;
    margin: 24px 0;
    color: var(--bk-blue);
    box-shadow: var(--bk-shadow);
}

.bk-hero-formula .bk-coeff {
    color: var(--bk-red);
    font-weight: 700;
}

.bk-hero-desc {
    font-size: 1.05rem;
    color: #475569;
    line-height: 1.8;
    margin-bottom: 28px;
}

.bk-hero-img {
    flex: 1;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--bk-shadow);
}

/* --- 卡片 --- */
.bk-card {
    background: var(--bk-white);
    border-radius: var(--bk-radius);
    box-shadow: var(--bk-shadow);
    overflow: hidden;
    transition: transform var(--bk-transition), box-shadow var(--bk-transition);
}

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

.bk-card-img {
    width: 100%;
    aspect-ratio: 16/9;
    object-fit: cover;
}

.bk-card-body {
    padding: 20px;
}

.bk-card-tag {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 20px;
    background: rgba(51,102,255,0.1);
    color: var(--bk-blue);
    margin-bottom: 8px;
}

.bk-card-tag--hot {
    background: rgba(255,77,79,0.1);
    color: var(--bk-red);
}

.bk-card-title {
    font-size: 1.05rem;
    margin-bottom: 8px;
    line-height: 1.4;
}

.bk-card-meta {
    font-size: 0.85rem;
    color: #94A3B8;
}

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

/* --- 按钮 --- */
.bk-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 28px;
    font-size: 0.95rem;
    font-weight: 600;
    border: none;
    border-radius: var(--bk-radius);
    cursor: pointer;
    transition: all var(--bk-transition);
    text-decoration: none;
}

.bk-btn-primary {
    background: linear-gradient(135deg, var(--bk-blue), #5580FF);
    color: var(--bk-white);
    box-shadow: 0 4px 14px rgba(51,102,255,0.3);
}

.bk-btn-primary:hover {
    background: linear-gradient(135deg, var(--bk-blue-hover), var(--bk-blue));
    box-shadow: 0 6px 20px rgba(51,102,255,0.4);
    color: var(--bk-white);
    transform: translateY(-1px);
}

.bk-btn-outline {
    background: transparent;
    color: var(--bk-blue);
    border: 2px solid var(--bk-blue);
}

.bk-btn-outline:hover {
    background: var(--bk-blue);
    color: var(--bk-white);
}

/* --- 实验台入口 --- */
.bk-lab-access {
    background: linear-gradient(135deg, #0A1F44 0%, #1a3a6e 100%);
    padding: 80px 0;
    color: var(--bk-white);
    text-align: center;
}

.bk-lab-access .bk-section-title {
    color: var(--bk-white);
}

.bk-lab-access .bk-section-subtitle {
    color: rgba(255,255,255,0.75);
    margin-left: auto;
    margin-right: auto;
}

.bk-search-box {
    display: flex;
    max-width: 640px;
    margin: 0 auto;
    background: var(--bk-white);
    border-radius: var(--bk-radius);
    overflow: hidden;
    box-shadow: 0 8px 32px rgba(0,0,0,0.2);
}

.bk-search-input {
    flex: 1;
    padding: 16px 20px;
    font-size: 0.95rem;
    border: none;
    outline: none;
    color: var(--bk-text);
    font-family: inherit;
}

.bk-search-input::placeholder {
    color: #94A3B8;
}

.bk-search-btn {
    padding: 16px 28px;
    background: var(--bk-blue);
    color: var(--bk-white);
    border: none;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--bk-transition);
    white-space: nowrap;
}

.bk-search-btn:hover {
    background: var(--bk-blue-hover);
}

/* --- 增长因子图谱 --- */
.bk-growth-atlas {
    padding: 80px 0;
}

.bk-atlas-visual {
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--bk-shadow);
    margin-top: 20px;
}

/* --- 失败案例复盘 --- */
.bk-failure-review {
    padding: 80px 0;
    background: var(--bk-light-gray);
}

.bk-failure-card {
    background: var(--bk-white);
    border-radius: var(--bk-radius);
    padding: 32px;
    box-shadow: var(--bk-shadow);
    border-left: 4px solid var(--bk-red);
    margin-bottom: 24px;
}

.bk-failure-card h3 {
    font-size: 1.15rem;
    margin-bottom: 12px;
    color: var(--bk-red);
}

.bk-failure-step {
    display: flex;
    gap: 20px;
    margin-top: 16px;
}

.bk-failure-step-item {
    flex: 1;
    padding: 16px;
    background: var(--bk-light-gray);
    border-radius: var(--bk-radius);
}

.bk-failure-step-item h4 {
    font-size: 0.9rem;
    color: var(--bk-blue);
    margin-bottom: 8px;
}

.bk-failure-step-item p {
    font-size: 0.88rem;
    color: #475569;
}

/* --- 流量趋势预测 --- */
.bk-trend-forecast {
    padding: 80px 0;
}

.bk-trend-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    align-items: center;
}

.bk-trend-list {
    list-style: none;
}

.bk-trend-list li {
    padding: 14px 0;
    border-bottom: 1px solid var(--bk-border);
    display: flex;
    align-items: center;
    gap: 12px;
}

.bk-trend-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--bk-blue);
    color: var(--bk-white);
    font-size: 0.75rem;
    font-weight: 700;
    flex-shrink: 0;
}

.bk-trend-badge--up {
    background: #10B981;
}

.bk-trend-badge--new {
    background: var(--bk-red);
}

/* --- 工具试剂库 --- */
.bk-tools-library {
    padding: 80px 0;
    background: var(--bk-light-gray);
}

.bk-tool-card {
    background: var(--bk-white);
    border-radius: var(--bk-radius);
    padding: 28px;
    box-shadow: var(--bk-shadow);
    text-align: center;
    transition: transform var(--bk-transition), box-shadow var(--bk-transition);
}

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

.bk-tool-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 16px;
    background: rgba(51,102,255,0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.bk-tool-card h3 {
    font-size: 1.05rem;
    margin-bottom: 8px;
}

.bk-tool-card p {
    font-size: 0.88rem;
    color: #64748B;
}

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

/* --- 首席研究员专栏 --- */
.bk-scientist-column {
    padding: 80px 0;
}

.bk-scientist-grid {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 40px;
    align-items: start;
}

.bk-scientist-profile {
    text-align: center;
    padding: 32px;
    background: var(--bk-light-gray);
    border-radius: var(--bk-radius);
}

.bk-scientist-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    margin: 0 auto 16px;
    background: linear-gradient(135deg, var(--bk-blue), #5580FF);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--bk-white);
    font-size: 2.5rem;
    font-weight: 700;
}

.bk-scientist-name {
    font-size: 1.15rem;
    margin-bottom: 4px;
}

.bk-scientist-title-text {
    font-size: 0.88rem;
    color: #64748B;
}

.bk-article-list {
    list-style: none;
}

.bk-article-list li {
    padding: 20px 0;
    border-bottom: 1px solid var(--bk-border);
}

.bk-article-list li:last-child {
    border-bottom: none;
}

.bk-article-list h3 {
    font-size: 1.1rem;
    margin-bottom: 8px;
}

.bk-article-list h3 a {
    color: var(--bk-text);
}

.bk-article-list h3 a:hover {
    color: var(--bk-blue);
}

.bk-article-list p {
    font-size: 0.9rem;
    color: #64748B;
    line-height: 1.6;
}

.bk-article-date {
    font-size: 0.8rem;
    color: #94A3B8;
    margin-top: 6px;
}

/* --- 数据报告订阅 --- */
.bk-subscribe {
    padding: 80px 0;
    background: var(--bk-light-gray);
    text-align: center;
}

.bk-subscribe-form {
    display: flex;
    max-width: 480px;
    margin: 0 auto;
    gap: 12px;
}

.bk-subscribe-input {
    flex: 1;
    padding: 14px 18px;
    font-size: 0.95rem;
    border: 2px solid var(--bk-border);
    border-radius: var(--bk-radius);
    outline: none;
    transition: border-color var(--bk-transition);
    font-family: inherit;
}

.bk-subscribe-input:focus {
    border-color: var(--bk-blue);
}

/* --- 合作与投稿 --- */
.bk-collaboration {
    padding: 80px 0;
}

.bk-collab-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
}

.bk-collab-card {
    padding: 36px;
    border-radius: var(--bk-radius);
    box-shadow: var(--bk-shadow);
    background: var(--bk-white);
}

.bk-collab-card h3 {
    font-size: 1.2rem;
    margin-bottom: 12px;
    color: var(--bk-blue);
}

.bk-collab-card p {
    font-size: 0.92rem;
    color: #475569;
    margin-bottom: 20px;
    line-height: 1.7;
}

/* --- 页脚 --- */
.bk-footer {
    background: var(--bk-light-gray);
    padding: 60px 0 30px;
    border-top: 1px solid var(--bk-border);
}

.bk-footer-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.bk-footer-col h4 {
    font-size: 1rem;
    margin-bottom: 16px;
    color: var(--bk-text);
}

.bk-footer-links {
    list-style: none;
}

.bk-footer-links li {
    margin-bottom: 10px;
}

.bk-footer-links a {
    font-size: 0.9rem;
    color: #64748B;
    transition: color var(--bk-transition);
}

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

.bk-footer-social {
    display: flex;
    gap: 16px;
    margin-top: 8px;
}

.bk-footer-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--bk-white);
    color: #64748B;
    transition: all var(--bk-transition);
    font-size: 0.85rem;
    font-weight: 600;
}

.bk-footer-social a:hover {
    background: var(--bk-blue);
    color: var(--bk-white);
}

.bk-footer-bottom {
    border-top: 1px solid var(--bk-border);
    padding-top: 24px;
    text-align: center;
    font-size: 0.82rem;
    color: #94A3B8;
    line-height: 2;
}

.bk-footer-bottom a {
    color: #64748B;
}

.bk-footer-bottom a:hover {
    color: var(--bk-blue);
}

.bk-footer-honor {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin: 6px 0;
    font-size: 0.82rem;
    color: #64748B;
}

/* --- 内页通用 --- */
.bk-page-hero {
    background: var(--bk-light-gray);
    padding: 60px 0;
    text-align: center;
}

.bk-page-hero h1 {
    font-size: 2rem;
    margin-bottom: 12px;
}

.bk-page-hero p {
    font-size: 1rem;
    color: #64748B;
    max-width: 600px;
    margin: 0 auto;
}

.bk-content {
    padding: 60px 0;
}

.bk-content-body {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1rem;
    line-height: 1.85;
}

.bk-content-body h2 {
    font-size: 1.5rem;
    margin: 40px 0 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--bk-blue);
    display: inline-block;
}

.bk-content-body h3 {
    font-size: 1.2rem;
    margin: 28px 0 12px;
}

.bk-content-body p {
    margin-bottom: 16px;
    color: #334155;
}

.bk-content-body img {
    border-radius: var(--bk-radius);
    margin: 24px 0;
    box-shadow: var(--bk-shadow);
}

.bk-data-table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    font-size: 0.9rem;
}

.bk-data-table th,
.bk-data-table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--bk-border);
}

.bk-data-table th {
    background: var(--bk-light-gray);
    font-weight: 600;
    color: var(--bk-text);
}

.bk-data-table tr:hover td {
    background: rgba(51,102,255,0.03);
}

/* --- 实验台页面 --- */
.bk-lab-page {
    padding: 60px 0;
}

.bk-lab-input-area {
    text-align: center;
    margin-bottom: 48px;
}

.bk-lab-result {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 32px;
}

.bk-lab-tabs {
    display: flex;
    gap: 0;
    border-bottom: 2px solid var(--bk-border);
    margin-bottom: 24px;
}

.bk-lab-tab {
    padding: 12px 20px;
    font-size: 0.9rem;
    font-weight: 600;
    color: #64748B;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all var(--bk-transition);
    background: none;
    border-top: none;
    border-left: none;
    border-right: none;
    font-family: inherit;
}

.bk-lab-tab.bk-active {
    color: var(--bk-blue);
    border-bottom-color: var(--bk-blue);
}

.bk-lab-tab:hover {
    color: var(--bk-blue);
}

.bk-lab-panel {
    display: none;
    padding: 20px;
    background: var(--bk-white);
    border-radius: var(--bk-radius);
    box-shadow: var(--bk-shadow);
}

.bk-lab-panel.bk-active {
    display: block;
}

.bk-lab-interpret {
    padding: 24px;
    background: var(--bk-light-gray);
    border-radius: var(--bk-radius);
    position: relative;
}

.bk-lab-interpret h3 {
    font-size: 1.1rem;
    margin-bottom: 16px;
    color: var(--bk-blue);
}

.bk-lab-interpret p {
    font-size: 0.92rem;
    color: #475569;
    line-height: 1.75;
    margin-bottom: 12px;
}

.bk-loading {
    text-align: center;
    padding: 60px 20px;
}

.bk-spinner {
    width: 48px;
    height: 48px;
    border: 3px solid var(--bk-border);
    border-top-color: var(--bk-blue);
    border-radius: 50%;
    animation: bk-spin 0.8s linear infinite;
    margin: 0 auto 20px;
}

@keyframes bk-spin {
    to { transform: rotate(360deg); }
}

.bk-loading-text {
    font-size: 0.95rem;
    color: #64748B;
    font-family: "Roboto Mono", monospace;
}

/* --- APP下载页 --- */
.bk-app-hero {
    background: linear-gradient(135deg, #0A1F44 0%, #0d2b5e 50%, #112d4e 100%);
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--bk-white);
    position: relative;
    overflow: hidden;
    padding: 80px 20px;
}

.bk-app-matrix {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0.08;
    font-family: "Roboto Mono", monospace;
    font-size: 14px;
    line-height: 1.8;
    color: var(--bk-blue);
    overflow: hidden;
    pointer-events: none;
}

.bk-app-content {
    position: relative;
    z-index: 2;
    max-width: 700px;
}

.bk-app-content h1 {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.bk-app-content p {
    font-size: 1.1rem;
    color: rgba(255,255,255,0.8);
    margin-bottom: 36px;
    line-height: 1.7;
}

.bk-app-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.bk-app-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 28px;
    background: var(--bk-white);
    color: var(--bk-text);
    border-radius: var(--bk-radius);
    font-weight: 600;
    font-size: 0.95rem;
    transition: all var(--bk-transition);
}

.bk-app-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.3);
    color: var(--bk-text);
}

.bk-app-phone {
    max-width: 360px;
    margin: 40px auto 0;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0,0,0,0.4);
}

/* --- 动画 --- */
.bk-fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.bk-fade-in.bk-visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- 响应式 --- */
@media (max-width: 1440px) {
    .bk-container {
        max-width: 1140px;
    }
}

@media (max-width: 1024px) {
    .bk-hero-inner {
        flex-direction: column;
    }

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

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

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

    .bk-scientist-grid {
        grid-template-columns: 1fr;
    }

    .bk-trend-grid {
        grid-template-columns: 1fr;
    }

    .bk-lab-result {
        grid-template-columns: 1fr;
    }

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

@media (max-width: 768px) {
    .bk-nav-links {
        display: none;
    }

    .bk-hamburger {
        display: flex;
    }

    .bk-mobile-menu {
        display: block;
    }

    .bk-section {
        padding: 48px 0;
    }

    .bk-section-alt {
        padding: 48px 0;
    }

    .bk-hero {
        padding: 60px 0 48px;
    }

    .bk-hero-content h1 {
        font-size: 1.75rem;
    }

    .bk-card-grid {
        grid-template-columns: 1fr;
    }

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

    .bk-collab-grid {
        grid-template-columns: 1fr;
    }

    .bk-search-box {
        flex-direction: column;
    }

    .bk-search-btn {
        border-radius: 0 0 var(--bk-radius) var(--bk-radius);
    }

    .bk-subscribe-form {
        flex-direction: column;
    }

    .bk-failure-step {
        flex-direction: column;
    }

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

    .bk-page-hero h1 {
        font-size: 1.5rem;
    }

    .bk-app-content h1 {
        font-size: 1.75rem;
    }
}

@media (max-width: 360px) {
    html {
        font-size: 14px;
    }

    .bk-container {
        padding: 0 16px;
    }

    .bk-hero-content h1 {
        font-size: 1.5rem;
    }

    .bk-tool-grid {
        grid-template-columns: 1fr;
    }
}

/* --- APP功能区 --- */
.bk-app-features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.bk-app-feature {
    background: var(--bk-white);
    padding: 28px;
    border-radius: var(--bk-radius);
    box-shadow: var(--bk-shadow);
    text-align: center;
    transition: transform var(--bk-transition), box-shadow var(--bk-transition);
}

.bk-app-feature:hover {
    transform: translateY(-4px);
    box-shadow: var(--bk-shadow-hover);
}

.bk-app-feature-icon {
    font-size: 2rem;
    margin-bottom: 16px;
    width: 60px;
    height: 60px;
    margin-left: auto;
    margin-right: auto;
    background: rgba(51,102,255,0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.bk-app-feature h3 {
    font-size: 1.05rem;
    margin-bottom: 8px;
}

.bk-app-feature p {
    font-size: 0.88rem;
    color: #64748B;
    line-height: 1.7;
}

@media (max-width: 1024px) {
    .bk-app-features {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .bk-app-features {
        grid-template-columns: 1fr;
    }
}

/* --- 增长因子图谱响应式 --- */
@media (max-width: 768px) {
    .bk-growth-atlas [style*="grid-template-columns:repeat(4"] {
        grid-template-columns: repeat(2, 1fr) !important;
    }
}

@media (max-width: 360px) {
    .bk-growth-atlas [style*="grid-template-columns:repeat(4"] {
        grid-template-columns: 1fr !important;
    }
}

/* --- 实验台选项卡响应式 --- */
@media (max-width: 768px) {
    .bk-lab-tabs {
        flex-wrap: wrap;
    }
    .bk-lab-tab {
        font-size: 0.82rem;
        padding: 10px 14px;
    }
}