:root {
    --container: 1180px;
    --primary-color: #007aff;
    --primary-light: #e8f4ff;
    --secondary-color: #34c759;
    --warning-color: #ff9500;
    --danger-color: #ff3b30;
    --info-color: #5ac8fa;
    --text-primary: #1a1a1a;
    --text-secondary: #666;
    --text-light: #999;
    --border-color: #e0e0e0;
    --bg-light: #f8f9fa;
    --bg-white: #ffffff;
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-primary);
    background: var(--bg-white);
    line-height: 1.6;
}

.container {
    width: min(100% - 32px, var(--container));
    margin-inline: auto;
}

/* 图片统一设置 */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

.image-box,
.radio-media,
.signal-media,
.preview-media,
.phone-screen,
.app-screenshot {
    overflow: visible;
    line-height: 0;
}

.image-box img,
.radio-media img,
.signal-media img,
.preview-media img,
.phone-screen img,
.app-screenshot {
    max-width: 100%;
    height: auto;
    object-fit: contain;
}

/* ===== 电台状态栏 ===== */
.radio-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
    transition: var(--transition);
    height: 70px;
}

.radio-header.scrolled {
    height: 60px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
    width: min(100% - 32px, var(--container));
    margin: 0 auto;
    padding: 0 16px;
    transition: var(--transition);
}

.radio-header.scrolled .header-container {
    height: 60px;
}

.header-left {
    flex: 1;
}

.logo-group {
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
}

.logo-icon {
    width: 40px;
    height: 40px;
}

.logo-text {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
}

.header-center {
    flex: 2;
    text-align: center;
}

.frequency-display {
    font-size: 14px;
    color: var(--text-secondary);
}

.frequency-label {
    color: var(--text-light);
}

.frequency-text {
    color: var(--primary-color);
    font-weight: 500;
}

.header-right {
    flex: 1;
    text-align: right;
}

.channel-nav {
    display: flex;
    gap: 24px;
}

.channel-btn {
    background: none;
    border: none;
    font-size: 14px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    font-weight: 500;
}

.channel-btn:hover {
    color: var(--primary-color);
}

.channel-btn.active {
    color: var(--primary-color);
}

.channel-btn.active::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
}

.progress-bar {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 2px;
    background: var(--primary-color);
    width: 0;
    transition: width 0.1s linear;
}

/* ===== Hero 区域 ===== */
main {
    margin-top: 70px;
    transition: var(--transition);
}

.radio-header.scrolled ~ main {
    margin-top: 60px;
}

.hero-section {
    background: linear-gradient(135deg, var(--primary-light) 0%, rgba(232, 244, 255, 0.5) 100%);
    padding: 60px 16px;
    position: relative;
}

.hero-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    margin-bottom: 60px;
}

.frequency-badge {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 24px;
    letter-spacing: 1px;
}

.hero-title {
    font-size: 42px;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.hero-text {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 32px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 32px;
}

.btn {
    padding: 12px 32px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: #0051cc;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.3);
}

.btn-secondary {
    background: var(--bg-white);
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-secondary:hover {
    background: var(--primary-light);
    transform: translateY(-2px);
}

.security-tip {
    display: flex;
    align-items: center;
    gap: 12px;
    background: rgba(255, 59, 48, 0.1);
    border-left: 3px solid var(--danger-color);
    padding: 12px 16px;
    border-radius: 4px;
    font-size: 13px;
    color: #d32f2f;
}

.tip-icon {
    font-size: 16px;
}

/* Hero 电台面板 */
.hero-panel {
    display: flex;
    justify-content: center;
}

.radio-window {
    background: var(--bg-white);
    border-radius: 16px;
    padding: 16px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 400px;
}

.radio-media {
    margin-bottom: 16px;
    border-radius: 12px;
    overflow: hidden;
}

.radio-media img {
    width: 100%;
    height: auto;
}

.radio-controls {
    padding: 0 16px;
}

.frequency-scale {
    display: flex;
    justify-content: space-between;
    font-size: 11px;
    color: var(--text-light);
    margin-bottom: 12px;
    padding: 0 8px;
}

.signal-lights {
    display: flex;
    gap: 6px;
    justify-content: center;
}

.signal-light {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #e0e0e0;
    transition: var(--transition);
}

.signal-light.on {
    background: var(--secondary-color);
    box-shadow: 0 0 8px var(--secondary-color);
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* 频率卡片 */
.frequency-cards {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.freq-card {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.freq-card:hover {
    border-color: var(--primary-color);
    box-shadow: 0 4px 16px rgba(0, 122, 255, 0.1);
    transform: translateY(-4px);
}

.freq-icon {
    font-size: 32px;
    margin-bottom: 12px;
}

.freq-label {
    font-size: 14px;
    color: var(--text-primary);
    font-weight: 600;
}

/* ===== 频道选择台 ===== */
section {
    padding: 80px 16px;
    border-bottom: 1px solid var(--border-color);
}

section h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 48px;
    text-align: center;
    color: var(--text-primary);
}

.channel-selector-section .selector-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 60px;
    align-items: flex-start;
}

.selector-dial {
    display: flex;
    justify-content: center;
}

.dial-circle {
    position: relative;
    width: 260px;
    height: 260px;
    border-radius: 50%;
    border: 3px solid var(--primary-color);
    background: var(--primary-light);
}

.dial-channels {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.dial-btn {
    position: absolute;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
}

.dial-btn:nth-child(1) {
    top: -10px;
    left: 50%;
    transform: translateX(-50%);
}

.dial-btn:nth-child(2) {
    top: 30px;
    right: -20px;
}

.dial-btn:nth-child(3) {
    bottom: 30px;
    right: 30px;
}

.dial-btn:nth-child(4) {
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
}

.dial-btn:nth-child(5) {
    bottom: 30px;
    left: 30px;
}

.dial-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    box-shadow: 0 0 20px rgba(0, 122, 255, 0.4);
}

.dial-pointer {
    position: absolute;
    width: 8px;
    height: 60px;
    background: var(--primary-color);
    left: 50%;
    top: -10px;
    transform: translateX(-50%);
    border-radius: 4px;
    transition: transform 0.4s ease;
}

.channel-info-card {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 32px;
    display: none;
    animation: fadeIn 0.3s ease;
}

.channel-info-card.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.channel-info-card h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.info-subtitle {
    font-size: 13px;
    color: var(--text-light);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.info-list {
    list-style: none;
    margin-bottom: 24px;
}

.info-list li {
    padding: 8px 0;
    padding-left: 24px;
    position: relative;
    color: var(--text-secondary);
    font-size: 14px;
}

.info-list li:before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: 700;
}

.info-reminder {
    background: var(--primary-light);
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 13px;
    color: var(--primary-color);
    margin-bottom: 24px;
    border-left: 3px solid var(--primary-color);
}

.image-box {
    margin-top: 24px;
    border-radius: 8px;
    overflow: hidden;
}

.image-box img {
    width: 100%;
    height: auto;
}

/* ===== 资产信号谱 ===== */
.spectrum-tracks {
    display: grid;
    gap: 24px;
    margin-bottom: 40px;
}

.spectrum-track {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
    cursor: pointer;
    transition: var(--transition);
}

.spectrum-track:hover {
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.1);
}

.track-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.track-label {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.track-status {
    font-size: 12px;
    padding: 4px 12px;
    background: var(--secondary-color);
    color: white;
    border-radius: 4px;
}

.track-wave {
    height: 60px;
    margin-bottom: 16px;
    overflow: hidden;
    border-radius: 8px;
    background: var(--bg-light);
    display: flex;
    align-items: center;
}

.waveform {
    width: 100%;
    height: 100%;
    color: var(--primary-color);
    opacity: 0.6;
}

.spectrum-track:hover .waveform {
    opacity: 1;
}

.track-description {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.track-expand {
    background: var(--primary-light);
    border: none;
    color: var(--primary-color);
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 13px;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

.track-expand:hover {
    background: var(--primary-color);
    color: white;
}

/* ===== 功能广播室 ===== */
.broadcast-layout {
    display: grid;
    grid-template-columns: 240px 1fr;
    gap: 40px;
}

.program-list {
    display: flex;
    flex-direction: column;
    gap: 0;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.program-item {
    background: var(--bg-white);
    border: none;
    border-bottom: 1px solid var(--border-color);
    padding: 16px;
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 14px;
}

.program-item:last-child {
    border-bottom: none;
}

.program-item.active {
    background: var(--primary-light);
    color: var(--primary-color);
    font-weight: 600;
    border-left: 4px solid var(--primary-color);
    padding-left: 12px;
}

.program-item:hover {
    background: var(--bg-light);
}

.program-number {
    font-size: 12px;
    color: var(--text-light);
    min-width: 20px;
}

.program-name {
    flex: 1;
}

.program-arrow {
    font-size: 12px;
    opacity: 0;
    transition: var(--transition);
}

.program-item.active .program-arrow {
    opacity: 1;
}

.program-content {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.program-panel {
    display: none;
    animation: fadeIn 0.3s ease;
}

.program-panel.active {
    display: block;
}

.program-panel h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.content-text {
    margin-bottom: 24px;
}

.content-text p {
    margin-bottom: 12px;
    font-size: 14px;
    line-height: 1.8;
    color: var(--text-secondary);
}

.content-text strong {
    color: var(--text-primary);
}

/* ===== 安全警报频道 ===== */
.alert-layout {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 40px;
}

.alert-buttons {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.alert-btn {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 16px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    text-align: center;
    font-size: 12px;
}

.alert-btn.active {
    border-color: var(--danger-color);
    background: rgba(255, 59, 48, 0.1);
}

.alert-btn:hover {
    border-color: var(--danger-color);
}

.alert-icon {
    font-size: 24px;
}

.alert-name {
    font-weight: 600;
    color: var(--text-primary);
}

.alert-content {
    display: none;
    animation: fadeIn 0.3s ease;
}

.alert-content.active {
    display: block;
}

.alert-content h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.alert-level {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
    font-size: 14px;
}

.level-badge {
    padding: 4px 12px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 600;
    color: white;
}

.level-badge.danger {
    background: var(--danger-color);
}

.level-badge.warning {
    background: var(--warning-color);
}

.level-badge.info {
    background: var(--info-color);
}

.alert-reason,
.alert-action {
    margin-bottom: 20px;
}

.alert-reason strong,
.alert-action strong {
    display: block;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 14px;
}

.alert-reason ul,
.alert-action ul {
    list-style: none;
    padding-left: 0;
}

.alert-reason li,
.alert-action li {
    padding: 6px 0 6px 24px;
    position: relative;
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.alert-reason li:before {
    content: '•';
    position: absolute;
    left: 8px;
    color: var(--text-light);
}

.alert-action li:before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
}

/* ===== App 界面频道 ===== */
.app-viewer {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: flex-start;
}

.app-preview {
    display: flex;
    justify-content: center;
    sticky: top 100px;
}

.phone-frame {
    width: 100%;
    max-width: 280px;
    aspect-ratio: 9 / 16;
    background: var(--text-primary);
    border-radius: 30px;
    padding: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.2);
    border: 8px solid var(--text-primary);
    position: relative;
}

.phone-frame::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 150px;
    height: 25px;
    background: var(--text-primary);
    border-radius: 0 0 30px 30px;
    z-index: 10;
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: var(--bg-white);
    border-radius: 25px;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.app-screenshot {
    width: 100%;
    height: 100%;
}

.app-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.screen-nav {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.screen-btn {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-size: 14px;
}

.screen-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.screen-btn:hover {
    border-color: var(--primary-color);
}

.screen-content {
    display: none;
    animation: fadeIn 0.3s ease;
}

.screen-content.active {
    display: block;
}

.screen-content h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.screen-content p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 16px;
}

.info-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag {
    background: var(--primary-light);
    color: var(--primary-color);
    padding: 6px 12px;
    border-radius: 4px;
    font-size: 12px;
}

/* ===== 网络接收器 ===== */
.receiver-segments {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 40px;
}

.receiver-segment {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
    transition: var(--transition);
}

.receiver-segment:hover {
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.1);
}

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

.status-light {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    transition: var(--transition);
}

.status-light.green {
    background: var(--secondary-color);
}

.segment-header h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.segment-text {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.segment-confirm {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 12px;
}

.confirm-badge {
    background: var(--warning-color);
    color: white;
    padding: 4px 8px;
    border-radius: 3px;
    font-weight: 600;
}

.confirm-tip {
    color: var(--text-light);
    cursor: help;
    position: relative;
}

.receiver-image {
    margin-top: 40px;
}

/* ===== 场景点播台 ===== */
.carousel-layout {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: 40px;
}

.carousel-buttons {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.carousel-btn {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 16px;
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
}

.carousel-btn.active {
    background: var(--primary-light);
    border-color: var(--primary-color);
}

.carousel-btn:hover {
    border-color: var(--primary-color);
}

.scenario-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-primary);
}

.carousel-arrow {
    font-size: 12px;
    color: var(--text-light);
    transition: var(--transition);
    flex-shrink: 0;
}

.carousel-btn.active .carousel-arrow {
    color: var(--primary-color);
}

.carousel-content {
    display: flex;
    flex-direction: column;
}

.scenario-card {
    display: none;
    animation: fadeIn 0.3s ease;
}

.scenario-card.active {
    display: block;
}

.scenario-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.scenario-text {
    margin-bottom: 24px;
}

.scenario-text p {
    margin-bottom: 12px;
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.8;
}

.scenario-text strong {
    display: block;
    color: var(--text-primary);
    margin-top: 12px;
    margin-bottom: 8px;
}

.scenario-text ul {
    list-style: none;
    padding: 0;
}

.scenario-text li {
    padding: 6px 0 6px 24px;
    position: relative;
    font-size: 13px;
    color: var(--text-secondary);
}

.scenario-text li:before {
    content: '•';
    position: absolute;
    left: 8px;
}

/* ===== 前置操作检查 ===== */
.checklist-panel {
    background: var(--bg-light);
    border-radius: 12px;
    padding: 40px;
}

.checklist-items {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 16px;
    margin-bottom: 32px;
}

.checklist-item {
    background: var(--bg-white);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 16px;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.checklist-item.checked {
    border-color: var(--secondary-color);
    background: rgba(52, 199, 89, 0.1);
}

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

.check-icon {
    font-size: 20px;
    transition: var(--transition);
}

.checklist-item.checked .check-icon {
    color: var(--secondary-color);
}

.check-text {
    font-weight: 600;
    font-size: 13px;
    color: var(--text-primary);
}

.check-desc {
    font-size: 11px;
    color: var(--text-light);
}

.checklist-result {
    background: var(--bg-white);
    border-left: 3px solid var(--secondary-color);
    padding: 16px;
    border-radius: 4px;
    text-align: center;
    display: none;
}

.checklist-result.show {
    display: block;
}

.result-text {
    font-size: 14px;
    color: var(--secondary-color);
    font-weight: 600;
}

/* ===== FAQ ===== */
.faq-layout {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 40px;
}

.faq-categories {
    display: flex;
    flex-direction: column;
    gap: 0;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.faq-cat-btn {
    background: var(--bg-white);
    border: none;
    border-bottom: 1px solid var(--border-color);
    padding: 16px;
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
}

.faq-cat-btn:last-child {
    border-bottom: none;
}

.faq-cat-btn.active {
    background: var(--primary-light);
    color: var(--primary-color);
    font-weight: 600;
    border-left: 4px solid var(--primary-color);
    padding-left: 12px;
}

.faq-cat-btn:hover {
    background: var(--bg-light);
}

.cat-arrow {
    font-size: 12px;
    opacity: 0;
    transition: var(--transition);
}

.faq-cat-btn.active .cat-arrow {
    opacity: 1;
}

.faq-items {
    display: flex;
    flex-direction: column;
}

.faq-category-group {
    display: none;
}

.faq-category-group.active {
    display: block;
}

.faq-item {
    border: 2px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 12px;
    overflow: hidden;
    transition: var(--transition);
}

.faq-item:hover {
    border-color: var(--primary-color);
    box-shadow: 0 2px 8px rgba(0, 122, 255, 0.1);
}

.faq-question {
    background: var(--bg-white);
    border: none;
    width: 100%;
    padding: 16px;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    transition: var(--transition);
}

.faq-question:hover {
    background: var(--bg-light);
}

.faq-toggle {
    font-size: 16px;
    transition: transform 0.3s ease;
    flex-shrink: 0;
}

.faq-item.open .faq-toggle {
    transform: rotate(45deg);
}

.faq-answer {
    display: none;
    padding: 16px;
    background: var(--bg-light);
    border-top: 1px solid var(--border-color);
    animation: slideDown 0.3s ease;
}

.faq-item.open .faq-answer {
    display: block;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.faq-answer p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin: 0;
}

/* ===== Footer ===== */
.radio-footer {
    background: var(--text-primary);
    color: white;
    padding: 60px 16px 40px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
    width: min(100% - 32px, var(--container));
    margin-left: auto;
    margin-right: auto;
}

.footer-section h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-light);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.footer-logo-icon {
    width: 32px;
    height: 32px;
}

.footer-logo-text {
    font-size: 16px;
    font-weight: 600;
}

.footer-desc {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

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

.footer-links li {
    margin-bottom: 12px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 13px;
    transition: var(--transition);
}

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

.footer-safety {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 24px;
    width: min(100% - 32px, var(--container));
    margin-left: auto;
    margin-right: auto;
}

.disclaimer {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: 12px;
    line-height: 1.6;
}

.copyright {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.5);
}

/* ===== 返回顶部按钮 ===== */
.scroll-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    transition: var(--transition);
    opacity: 0;
    pointer-events: none;
    z-index: 50;
}

.scroll-to-top.show {
    opacity: 1;
    pointer-events: auto;
}

.scroll-to-top:hover {
    background: #0051cc;
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(0, 122, 255, 0.3);
}

/* ===== 图片预览层 ===== */
.image-preview {
    position: fixed;
    inset: 0;
    z-index: 200;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.image-preview.show {
    opacity: 1;
    pointer-events: auto;
}

.preview-overlay {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.8);
}

.preview-container {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.preview-image {
    max-width: 90%;
    max-height: 90%;
    object-fit: contain;
    border-radius: 8px;
}

.preview-close {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 24px;
    cursor: pointer;
    transition: var(--transition);
}

.preview-close:hover {
    background: rgba(255, 255, 255, 0.4);
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
    .radio-header {
        height: 60px;
    }

    .header-container {
        height: 60px;
        gap: 16px;
    }

    .header-center {
        display: none;
    }

    .header-right {
        flex: none;
    }

    .channel-nav {
        gap: 12px;
    }

    .channel-btn {
        font-size: 12px;
    }

    main {
        margin-top: 60px;
    }

    section {
        padding: 60px 16px;
    }

    section h2 {
        font-size: 24px;
        margin-bottom: 32px;
    }

    .hero-section {
        padding: 40px 16px;
    }

    .hero-layout {
        grid-template-columns: 1fr;
        gap: 40px;
        margin-bottom: 40px;
    }

    .hero-title {
        font-size: 28px;
    }

    .frequency-cards {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }

    .channel-selector-section .selector-layout {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .selector-dial {
        max-width: 240px;
        margin: 0 auto;
    }

    .dial-circle {
        width: 220px;
        height: 220px;
    }

    .dial-btn {
        width: 50px;
        height: 50px;
        font-size: 11px;
    }

    .broadcast-layout {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .program-list {
        max-width: 100%;
    }

    .alert-layout {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .alert-buttons {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 12px;
    }

    .app-viewer {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .app-preview {
        position: static;
    }

    .receiver-segments {
        grid-template-columns: 1fr;
    }

    .carousel-layout {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .carousel-buttons {
        max-width: 100%;
    }

    .checklist-items {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .faq-layout {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .faq-categories {
        display: flex;
        flex-direction: row;
        gap: 12px;
        border: none;
        overflow-x: auto;
    }

    .faq-cat-btn {
        border: 2px solid var(--border-color);
        border-radius: 8px;
        border-bottom: 2px solid var(--border-color);
        padding: 12px 16px;
        white-space: nowrap;
        flex-shrink: 0;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .scroll-to-top {
        bottom: 16px;
        right: 16px;
        width: 44px;
        height: 44px;
        font-size: 18px;
    }
}

@media (max-width: 414px) {
    :root {
        --container: 375px;
    }

    .radio-header,
    .radio-header.scrolled {
        height: 56px;
    }

    .header-container,
    .radio-header.scrolled .header-container {
        height: 56px;
        padding: 0 12px;
    }

    .logo-icon {
        width: 32px;
        height: 32px;
    }

    .logo-text {
        font-size: 14px;
    }

    .frequency-display {
        font-size: 12px;
    }

    .channel-btn {
        font-size: 11px;
        padding: 4px 12px;
    }

    main {
        margin-top: 56px;
    }

    section {
        padding: 40px 12px;
    }

    section h2 {
        font-size: 20px;
        margin-bottom: 24px;
    }

    .hero-section {
        padding: 32px 12px;
    }

    .hero-layout {
        margin-bottom: 32px;
    }

    .frequency-badge {
        font-size: 11px;
        margin-bottom: 16px;
    }

    .hero-title {
        font-size: 22px;
        margin-bottom: 16px;
    }

    .hero-text {
        font-size: 14px;
        margin-bottom: 20px;
    }

    .hero-buttons {
        flex-direction: column;
        gap: 12px;
        margin-bottom: 20px;
    }

    .btn {
        padding: 10px 20px;
        font-size: 13px;
    }

    .security-tip {
        font-size: 12px;
        padding: 10px 12px;
    }

    .frequency-cards {
        grid-template-columns: 1fr;
    }

    .radio-window {
        max-width: 100%;
    }

    .dial-circle {
        width: 180px;
        height: 180px;
    }

    .dial-btn {
        width: 42px;
        height: 42px;
        font-size: 10px;
    }

    .channel-info-card {
        padding: 20px 16px;
    }

    .channel-info-card h3 {
        font-size: 18px;
        margin-bottom: 8px;
    }

    .info-subtitle {
        font-size: 12px;
    }

    .info-list li {
        padding: 6px 0 6px 20px;
        font-size: 13px;
    }

    .program-item {
        padding: 12px;
        font-size: 13px;
    }

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

    .alert-btn {
        padding: 12px;
        gap: 6px;
    }

    .alert-icon {
        font-size: 20px;
    }

    .alert-name {
        font-size: 11px;
    }

    .alert-content h3 {
        font-size: 18px;
        margin-bottom: 12px;
    }

    .alert-reason strong,
    .alert-action strong {
        font-size: 13px;
    }

    .alert-reason li,
    .alert-action li {
        font-size: 12px;
        padding: 4px 0 4px 20px;
    }

    .phone-frame {
        max-width: 240px;
    }

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

    .screen-content h3 {
        font-size: 16px;
    }

    .screen-content p {
        font-size: 13px;
    }

    .receiver-segment {
        padding: 16px;
    }

    .segment-header h3 {
        font-size: 14px;
    }

    .segment-text {
        font-size: 13px;
    }

    .carousel-btn {
        padding: 12px;
        gap: 8px;
    }

    .scenario-title {
        font-size: 12px;
    }

    .scenario-card h3 {
        font-size: 18px;
    }

    .checklist-items {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .checklist-panel {
        padding: 24px 16px;
    }

    .faq-question {
        padding: 12px;
        font-size: 13px;
    }

    .faq-answer {
        padding: 12px;
    }

    .faq-answer p {
        font-size: 13px;
    }

    .footer-content {
        gap: 20px;
    }

    .footer-section h4 {
        font-size: 12px;
    }

    .footer-logo-text {
        font-size: 14px;
    }

    .footer-desc {
        font-size: 12px;
    }

    .footer-links a {
        font-size: 12px;
    }

    .footer-safety {
        font-size: 12px;
    }

    .scroll-to-top {
        bottom: 12px;
        right: 12px;
        width: 40px;
        height: 40px;
    }
}

/* 移动端底部频道条 */
@media (max-width: 768px) {
    .mobile-channel-bar {
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        height: 60px;
        background: var(--bg-white);
        border-top: 1px solid var(--border-color);
        display: flex;
        justify-content: space-around;
        align-items: center;
        z-index: 99;
    }

    main {
        padding-bottom: 60px;
    }

    .mobile-channel-bar button {
        flex: 1;
        height: 100%;
        background: none;
        border: none;
        font-size: 12px;
        cursor: pointer;
        transition: var(--transition);
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 4px;
    }

    .mobile-channel-bar button.active {
        background: var(--primary-light);
        color: var(--primary-color);
    }
}

/* 动画和过渡 */
@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section-animate {
    animation: slideInUp 0.6s ease;
}