/* 
 * 困困兔 - 汽车改装与视频社区
 * 主样式表 - 赛道美学设计
 * 设计理念：速度与激情，改装与梦想
 */

/* ========== 全局样式 ========== */
:root {
    --primary-dark: #0F1419;      /* 深夜蓝 - 背景 */
    --primary-red: #E63946;       /* 赛道红 - 强调 */
    --primary-silver: #A8DADC;    /* 钛银灰 - 辅助 */
    --text-white: #FFFFFF;        /* 纯白 - 主文本 */
    --text-light: #E8E8E8;        /* 浅灰 - 副文本 */
    --border-color: #2A3038;      /* 边框 - 深灰 */
    --overlay: rgba(15, 20, 25, 0.8);  /* 半透明覆盖 */
    --transition: all 0.3s cubic-bezier(0.23, 1, 0.32, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--primary-dark);
    color: var(--text-white);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ========== 顶部导航栏 ========== */
.header-wrapper {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: linear-gradient(180deg, var(--primary-dark) 0%, rgba(15, 20, 25, 0.95) 100%);
    border-bottom: 2px solid var(--primary-red);
    box-shadow: 0 4px 20px rgba(230, 57, 70, 0.1);
}

.navbar {
    padding: 0.8rem 0;
}

.navbar-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.navbar-logo {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-white);
    transition: var(--transition);
}

.logo-img {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--primary-red);
}

.brand-name {
    background: linear-gradient(135deg, var(--primary-red), var(--primary-silver));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    flex: 1;
}

.nav-link {
    color: var(--text-light);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: var(--transition);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-red);
    transition: width 0.3s ease;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-red);
}

/* ========== 搜索框 ========== */
.search-container {
    display: flex;
    align-items: center;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 0.5rem 1rem;
    transition: var(--transition);
}

.search-container:focus-within {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary-red);
    box-shadow: 0 0 20px rgba(230, 57, 70, 0.3);
}

.search-input {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-white);
    font-size: 0.9rem;
    outline: none;
    padding: 0.5rem;
}

.search-input::placeholder {
    color: var(--text-light);
    opacity: 0.6;
}

.search-btn {
    background: transparent;
    border: none;
    color: var(--primary-red);
    cursor: pointer;
    font-size: 1.2rem;
    transition: var(--transition);
}

.search-btn:hover {
    transform: scale(1.2);
}

/* ========== 汉堡菜单 ========== */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 6px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--primary-red);
    border-radius: 2px;
    transition: var(--transition);
}

/* ========== Hero 区域 ========== */
.hero-section {
    position: relative;
    height: 600px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(15, 20, 25, 0.7) 0%, rgba(230, 57, 70, 0.2) 100%);
}

.hero-content {
    position: relative;
    z-index: 10;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
    padding: 4rem;
    max-width: 1400px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.brand-highlight {
    background: linear-gradient(135deg, var(--primary-red), var(--primary-silver));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    display: block;
    font-size: 1.8rem;
    color: var(--primary-silver);
    font-weight: 500;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    max-width: 600px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 1.5rem;
}

.btn {
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn-primary {
    background: var(--primary-red);
    color: var(--text-white);
    box-shadow: 0 4px 20px rgba(230, 57, 70, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(230, 57, 70, 0.6);
}

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

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

/* ========== 主内容区域 ========== */
.main-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* ========== 分割线 ========== */
.section-divider {
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--primary-red), transparent);
    margin: 4rem 0;
    position: relative;
    animation: slideLine 2s ease-in-out infinite;
}

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

/* ========== 章节标题 ========== */
.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
}

.title-icon {
    font-size: 2.8rem;
}

.section-subtitle {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

/* ========== 视频传媒模块 ========== */
.video-media-section {
    margin: 4rem 0;
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.video-card {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    transition: var(--transition);
    cursor: pointer;
}

.video-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-red);
    box-shadow: 0 20px 40px rgba(230, 57, 70, 0.2);
}

.video-thumbnail {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%;
    background-size: cover;
    background-position: center;
    overflow: hidden;
}

.play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background: rgba(230, 57, 70, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: white;
    opacity: 0;
    transition: var(--transition);
    box-shadow: 0 0 30px rgba(230, 57, 70, 0.5);
}

.video-card:hover .play-button {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1.1);
}

.video-overlay {
    position: absolute;
    top: 0;
    right: 0;
    padding: 1rem;
    background: linear-gradient(135deg, transparent, rgba(15, 20, 25, 0.8));
}

.video-duration {
    background: rgba(230, 57, 70, 0.8);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 600;
}

.video-info {
    padding: 1.5rem;
}

.video-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-white);
    line-height: 1.4;
}

.video-description {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 1rem;
    line-height: 1.5;
}

.video-stats {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.stat {
    font-size: 0.85rem;
    color: var(--primary-silver);
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.video-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.tag {
    background: rgba(230, 57, 70, 0.2);
    color: var(--primary-red);
    padding: 0.3rem 0.8rem;
    border-radius: 12px;
    font-size: 0.8rem;
    border: 1px solid rgba(230, 57, 70, 0.4);
}

/* ========== AI赋能模块 ========== */
.ai-section {
    margin: 4rem 0;
}

.ai-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.ai-feature-card {
    background: linear-gradient(135deg, rgba(230, 57, 70, 0.1), rgba(168, 216, 220, 0.05));
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
}

.ai-feature-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-red);
    box-shadow: 0 20px 40px rgba(230, 57, 70, 0.15);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 0.8rem;
}

.feature-description {
    font-size: 0.95rem;
    color: var(--text-light);
    line-height: 1.6;
}

/* ========== 社区功能模块 ========== */
.community-section {
    margin: 4rem 0;
}

.community-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.community-card {
    background: rgba(255, 255, 255, 0.02);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
}

.community-card:hover {
    border-color: var(--primary-red);
    background: rgba(230, 57, 70, 0.05);
    transform: translateY(-8px);
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.card-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.8rem;
}

.card-description {
    font-size: 0.95rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
}

.card-link {
    color: var(--primary-red);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
}

.card-link:hover {
    transform: translateX(4px);
}

/* ========== 专家展示模块 ========== */
.experts-section {
    margin: 4rem 0;
}

.experts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.expert-card {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
}

.expert-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-red);
    box-shadow: 0 20px 40px rgba(230, 57, 70, 0.15);
}

.expert-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    margin: 0 auto 1.5rem;
    background-size: cover;
    background-position: center;
    border: 3px solid var(--primary-red);
}

.expert-name {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 0.3rem;
}

.expert-title {
    font-size: 0.95rem;
    color: var(--primary-silver);
    margin-bottom: 0.8rem;
}

.expert-bio {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.expert-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.btn-small {
    padding: 0.5rem 1rem;
    background: rgba(230, 57, 70, 0.2);
    color: var(--primary-red);
    border: 1px solid var(--primary-red);
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    transition: var(--transition);
}

.btn-small:hover {
    background: var(--primary-red);
    color: var(--text-white);
}

/* ========== 合作品牌模块 ========== */
.partners-section {
    margin: 4rem 0;
}

.partners-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.partner-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    height: 120px;
    transition: var(--transition);
    cursor: pointer;
}

.partner-logo:hover {
    border-color: var(--primary-red);
    background: rgba(230, 57, 70, 0.05);
    transform: scale(1.05);
}

.logo-placeholder {
    font-size: 1rem;
    color: var(--text-light);
    text-align: center;
}

/* ========== 加入社区指南 ========== */
.join-guide-section {
    margin: 4rem 0;
}

.guide-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.step-card {
    background: linear-gradient(135deg, rgba(230, 57, 70, 0.1), rgba(168, 216, 220, 0.05));
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
    position: relative;
}

.step-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-red);
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background: var(--primary-red);
    color: white;
    border-radius: 50%;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.step-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.8rem;
}

.step-description {
    font-size: 0.95rem;
    color: var(--text-light);
    line-height: 1.6;
}

/* ========== FAQ模块 ========== */
.faq-section {
    margin: 4rem 0;
}

.faq-container {
    max-width: 900px;
    margin: 2rem auto;
}

.faq-item {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 1rem;
    overflow: hidden;
    transition: var(--transition);
}

.faq-item.active {
    border-color: var(--primary-red);
    background: rgba(230, 57, 70, 0.05);
}

.faq-question {
    padding: 1.5rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
    user-select: none;
}

.faq-question:hover {
    background: rgba(230, 57, 70, 0.05);
}

.faq-text {
    font-size: 1rem;
    font-weight: 600;
    flex: 1;
}

.faq-icon {
    font-size: 1.5rem;
    color: var(--primary-red);
    transition: var(--transition);
}

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

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    background: rgba(230, 57, 70, 0.02);
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

.faq-answer p {
    padding: 1.5rem;
    color: var(--text-light);
    line-height: 1.8;
}

/* ========== 用户评论模块 ========== */
.reviews-section {
    margin: 4rem 0;
}

.reviews-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.review-card {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    transition: var(--transition);
}

.review-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-red);
    box-shadow: 0 20px 40px rgba(230, 57, 70, 0.15);
}

.review-stars {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    letter-spacing: 2px;
}

.review-text {
    font-size: 0.95rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
    line-height: 1.8;
    min-height: 80px;
}

.review-author {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.author-avatar {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-red), var(--primary-silver));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.author-info {
    flex: 1;
}

.author-name {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.2rem;
}

.author-role {
    font-size: 0.85rem;
    color: var(--primary-silver);
}

/* ========== 联系我们模块 ========== */
.contact-section {
    margin: 4rem 0;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.contact-card {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    transition: var(--transition);
}

.contact-card:hover {
    border-color: var(--primary-red);
    background: rgba(230, 57, 70, 0.05);
}

.contact-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--primary-red);
}

.contact-item {
    display: flex;
    flex-direction: column;
    margin-bottom: 1rem;
}

.contact-label {
    font-size: 0.9rem;
    color: var(--text-light);
    font-weight: 600;
    margin-bottom: 0.3rem;
}

.contact-value {
    font-size: 0.95rem;
    color: var(--text-white);
}

.social-links {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.social-link {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: rgba(230, 57, 70, 0.1);
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-white);
    transition: var(--transition);
}

.social-link:hover {
    background: rgba(230, 57, 70, 0.2);
    transform: translateX(4px);
}

.social-icon {
    font-weight: 600;
    color: var(--primary-red);
    min-width: 50px;
}

.community-links {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.community-item {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}

.community-label {
    font-size: 0.9rem;
    color: var(--text-light);
    font-weight: 600;
}

.community-value {
    font-size: 0.95rem;
    color: var(--text-white);
}

.app-link {
    color: var(--primary-red);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.app-link:hover {
    text-decoration: underline;
}

.qr-section {
    text-align: center;
}

.qr-codes {
    display: flex;
    gap: 2rem;
    justify-content: center;
    margin-top: 1rem;
}

.qr-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.qr-placeholder {
    width: 120px;
    height: 120px;
    background: rgba(230, 57, 70, 0.1);
    border: 2px dashed var(--primary-red);
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    color: var(--text-light);
    text-align: center;
}

.qr-label {
    font-size: 0.9rem;
    color: var(--text-light);
}

/* ========== 底部 ========== */
.footer {
    background: linear-gradient(180deg, rgba(15, 20, 25, 0.95) 0%, var(--primary-dark) 100%);
    border-top: 2px solid var(--primary-red);
    margin-top: 4rem;
    padding: 3rem 2rem 1rem;
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section {
    display: flex;
    flex-direction: column;
}

.footer-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--primary-red);
}

.footer-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.footer-links a {
    color: var(--text-light);
    text-decoration: none;
    transition: var(--transition);
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: var(--primary-red);
    transform: translateX(4px);
}

.footer-bottom {
    max-width: 1400px;
    margin: 0 auto;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.copyright {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 0.5rem;
}

.copyright a {
    color: var(--primary-red);
    text-decoration: none;
    transition: var(--transition);
}

.copyright a:hover {
    text-decoration: underline;
}

.update-time {
    font-size: 0.8rem;
    color: var(--primary-silver);
}

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

.video-card,
.community-card,
.expert-card,
.review-card {
    animation: fadeInUp 0.6s ease-out;
}

/* ========== 滚动条样式 ========== */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--primary-dark);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-red);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-silver);
}