/* ============================================
   每日大赛 - 原创样式表
   配色：赛车红 #E63946 / 金属灰 #2B2D42 / 碳纤维黑 #1A1A2E / 银色 #8D99AE / 琥珀橙 #F77F00
   ============================================ */
:root {
  --racing-red: #E63946;
  --metal-gray: #2B2D42;
  --carbon-black: #1A1A2E;
  --silver: #8D99AE;
  --amber-orange: #F77F00;
  --light-bg: #F1FAEE;
  --white: #FFFFFF;
  --text-dark: #1D3557;
  --text-light: #A8DADC;
  --border-color: #E0E0E0;
}

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

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text-dark);
  background: var(--white);
  line-height: 1.7;
  overflow-x: hidden;
}

a { color: var(--racing-red); text-decoration: none; transition: color .25s; }
a:hover { color: var(--amber-orange); }

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

.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ---- Header / Navigation ---- */
.site-header {
  background: var(--carbon-black);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 12px rgba(0,0,0,.4);
}

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

.nav-logo { display: flex; align-items: center; gap: 10px; }
.nav-logo img { height: 42px; width: auto; }
.nav-logo span { color: var(--white); font-size: 22px; font-weight: 700; letter-spacing: 1px; }

.nav-menu { display: flex; list-style: none; gap: 6px; }
.nav-menu li a {
  color: #ccc;
  font-size: 15px;
  padding: 8px 14px;
  border-radius: 6px;
  transition: all .25s;
}
.nav-menu li a:hover,
.nav-menu li a.active {
  color: var(--white);
  background: var(--racing-red);
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--white);
  font-size: 26px;
  cursor: pointer;
}

/* ---- Search Bar ---- */
.search-bar {
  background: var(--metal-gray);
  padding: 12px 0;
}
.search-bar .container {
  display: flex;
  justify-content: center;
}
.search-box {
  display: flex;
  width: 100%;
  max-width: 600px;
  border-radius: 30px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,.3);
}
.search-box input {
  flex: 1;
  border: none;
  padding: 12px 20px;
  font-size: 15px;
  outline: none;
  background: var(--white);
  color: var(--text-dark);
}
.search-box button {
  background: var(--racing-red);
  color: var(--white);
  border: none;
  padding: 12px 28px;
  font-size: 15px;
  cursor: pointer;
  transition: background .25s;
  font-weight: 600;
}
.search-box button:hover { background: var(--amber-orange); }

/* ---- Hero Banner ---- */
.hero-banner {
  position: relative;
  height: 520px;
  background-size: cover;
  background-position: center;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}
.hero-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(26,26,46,.85) 0%, rgba(43,45,66,.7) 50%, rgba(230,57,70,.4) 100%);
}
.hero-content {
  position: relative;
  z-index: 2;
  color: var(--white);
  max-width: 800px;
  padding: 0 20px;
}
.hero-content h1 {
  font-size: 42px;
  font-weight: 800;
  margin-bottom: 16px;
  text-shadow: 0 3px 12px rgba(0,0,0,.5);
  line-height: 1.3;
}
.hero-content p {
  font-size: 18px;
  margin-bottom: 28px;
  opacity: .92;
  line-height: 1.7;
}
.hero-btn {
  display: inline-block;
  background: var(--racing-red);
  color: var(--white);
  padding: 14px 40px;
  border-radius: 30px;
  font-size: 17px;
  font-weight: 600;
  transition: all .3s;
  box-shadow: 0 4px 16px rgba(230,57,70,.4);
}
.hero-btn:hover {
  background: var(--amber-orange);
  transform: translateY(-2px);
  color: var(--white);
}

/* ---- Breadcrumb ---- */
.breadcrumb {
  padding: 14px 0;
  font-size: 14px;
  color: var(--silver);
  background: var(--light-bg);
}
.breadcrumb a { color: var(--metal-gray); }
.breadcrumb span { margin: 0 6px; }

/* ---- Section Common ---- */
.section {
  padding: 60px 0;
}
.section-alt {
  background: var(--light-bg);
}
.section-dark {
  background: var(--carbon-black);
  color: var(--white);
}
.section-title {
  text-align: center;
  margin-bottom: 42px;
}
.section-title h2 {
  font-size: 32px;
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 10px;
}
.section-dark .section-title h2 { color: var(--white); }
.section-title p {
  font-size: 16px;
  color: var(--silver);
  max-width: 650px;
  margin: 0 auto;
}

/* ---- Video Card Grid ---- */
.video-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.video-card {
  background: var(--white);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0,0,0,.08);
  transition: all .35s;
}
.video-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px rgba(230,57,70,.15);
}
.video-thumb {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16/9;
}
.video-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .4s;
}
.video-card:hover .video-thumb img { transform: scale(1.06); }

.play-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0);
  width: 60px;
  height: 60px;
  background: rgba(230,57,70,.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all .35s;
  box-shadow: 0 4px 20px rgba(0,0,0,.3);
}
.play-btn::after {
  content: "";
  display: block;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent #fff;
  margin-left: 3px;
}
.video-card:hover .play-btn { transform: translate(-50%, -50%) scale(1); }

.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,.75);
  color: #fff;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 600;
}

.video-info { padding: 14px 16px; }
.video-info h3 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 8px;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-meta {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--silver);
}
.video-meta span { display: flex; align-items: center; gap: 4px; }

/* ---- Service Cards ---- */
.service-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.service-card {
  background: var(--white);
  border-radius: 12px;
  padding: 32px 24px;
  text-align: center;
  box-shadow: 0 4px 16px rgba(0,0,0,.06);
  transition: all .3s;
  border-top: 4px solid transparent;
}
.service-card:hover {
  border-top-color: var(--racing-red);
  transform: translateY(-4px);
}
.service-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 18px;
  background: linear-gradient(135deg, var(--racing-red), var(--amber-orange));
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  color: var(--white);
}
.service-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}
.service-card p {
  font-size: 14px;
  color: var(--silver);
  line-height: 1.6;
}

/* ---- AI Section ---- */
.ai-section {
  position: relative;
  padding: 70px 0;
  background-size: cover;
  background-position: center;
}
.ai-section::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(to right, rgba(26,26,46,.92), rgba(26,26,46,.6));
}
.ai-content {
  position: relative;
  z-index: 2;
  color: var(--white);
}
.ai-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.ai-card {
  background: rgba(255,255,255,.08);
  backdrop-filter: blur(8px);
  border-radius: 12px;
  padding: 28px 22px;
  border: 1px solid rgba(255,255,255,.12);
  transition: all .3s;
}
.ai-card:hover {
  background: rgba(255,255,255,.14);
  transform: translateY(-4px);
}
.ai-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--amber-orange);
}
.ai-card p { font-size: 14px; opacity: .85; line-height: 1.6; }

/* ---- Expert Team ---- */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}
.expert-card {
  background: var(--white);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0,0,0,.06);
  text-align: center;
  transition: all .3s;
}
.expert-card:hover { transform: translateY(-4px); }
.expert-avatar {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
}
.expert-info { padding: 16px; }
.expert-info h3 { font-size: 17px; font-weight: 700; margin-bottom: 4px; }
.expert-info .role { font-size: 13px; color: var(--racing-red); margin-bottom: 8px; }
.expert-info p { font-size: 13px; color: var(--silver); line-height: 1.5; }
.expert-links { padding: 0 16px 16px; display: flex; gap: 8px; justify-content: center; }
.expert-links a {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
  transition: all .25s;
}
.expert-links .btn-primary { background: var(--racing-red); color: var(--white); }
.expert-links .btn-primary:hover { background: var(--amber-orange); color: var(--white); }
.expert-links .btn-outline { border: 1px solid var(--racing-red); color: var(--racing-red); }
.expert-links .btn-outline:hover { background: var(--racing-red); color: var(--white); }

/* ---- Community Section ---- */
.community-banner {
  position: relative;
  border-radius: 16px;
  overflow: hidden;
  margin-bottom: 36px;
}
.community-banner img { width: 100%; height: 300px; object-fit: cover; }
.community-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(26,26,46,.85), transparent);
  display: flex;
  align-items: flex-end;
  padding: 32px;
}
.community-overlay h3 { color: var(--white); font-size: 24px; }
.community-features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.community-feat {
  background: var(--white);
  border-radius: 10px;
  padding: 22px;
  box-shadow: 0 2px 10px rgba(0,0,0,.05);
  transition: all .3s;
}
.community-feat:hover { transform: translateY(-3px); }
.community-feat h4 { font-size: 16px; font-weight: 700; margin-bottom: 8px; color: var(--racing-red); }
.community-feat p { font-size: 13px; color: var(--silver); }

/* ---- Partner Logos ---- */
.partner-wall {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 32px;
  align-items: center;
}
.partner-logo {
  background: var(--white);
  border-radius: 10px;
  padding: 16px 28px;
  box-shadow: 0 2px 8px rgba(0,0,0,.06);
  font-size: 18px;
  font-weight: 700;
  color: var(--metal-gray);
  transition: all .3s;
}
.partner-logo:hover { box-shadow: 0 4px 16px rgba(230,57,70,.15); }

/* ---- HowTo Section ---- */
.howto-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  counter-reset: step;
}
.howto-step {
  text-align: center;
  padding: 28px 18px;
  background: var(--white);
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0,0,0,.05);
  position: relative;
  counter-increment: step;
}
.howto-step::before {
  content: counter(step);
  display: block;
  width: 48px;
  height: 48px;
  line-height: 48px;
  margin: 0 auto 14px;
  background: var(--racing-red);
  color: var(--white);
  border-radius: 50%;
  font-size: 20px;
  font-weight: 800;
}
.howto-step h4 { font-size: 16px; font-weight: 700; margin-bottom: 8px; }
.howto-step p { font-size: 13px; color: var(--silver); }

/* ---- FAQ ---- */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  border-bottom: 1px solid var(--border-color);
  padding: 18px 0;
}
.faq-question {
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-dark);
}
.faq-question::after {
  content: "+";
  font-size: 22px;
  font-weight: 300;
  color: var(--racing-red);
  transition: transform .3s;
}
.faq-item.active .faq-question::after { content: "−"; }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height .35s ease;
  font-size: 14px;
  color: var(--silver);
  line-height: 1.7;
  padding-top: 0;
}
.faq-item.active .faq-answer {
  max-height: 300px;
  padding-top: 12px;
}

/* ---- Reviews ---- */
.review-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.review-card {
  background: var(--white);
  border-radius: 12px;
  padding: 24px;
  box-shadow: 0 4px 16px rgba(0,0,0,.06);
}
.review-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}
.review-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--racing-red);
  color: var(--white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 700;
}
.review-name { font-weight: 700; font-size: 15px; }
.review-date { font-size: 12px; color: var(--silver); }
.review-stars { color: var(--amber-orange); font-size: 14px; margin-bottom: 8px; }
.review-text { font-size: 14px; color: #555; line-height: 1.6; }

/* ---- Contact Section ---- */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 36px;
}
.contact-info h3 { font-size: 20px; margin-bottom: 16px; }
.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 16px;
  font-size: 14px;
}
.contact-icon {
  width: 36px;
  height: 36px;
  background: var(--racing-red);
  color: var(--white);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
}
.qrcode-group {
  display: flex;
  gap: 24px;
  justify-content: center;
}
.qrcode-item { text-align: center; }
.qrcode-item img { width: 140px; height: 140px; border-radius: 8px; margin-bottom: 8px; }
.qrcode-item p { font-size: 13px; color: var(--silver); }

/* ---- Share Buttons ---- */
.share-bar {
  display: flex;
  gap: 12px;
  justify-content: center;
  padding: 20px 0;
}
.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  color: var(--white);
  transition: all .25s;
}
.share-btn:hover { opacity: .85; transform: translateY(-2px); color: var(--white); }
.share-wechat { background: #07C160; }
.share-weibo { background: #E6162D; }
.share-douyin { background: #161823; }
.share-bilibili { background: #00A1D6; }

/* ---- Footer ---- */
.site-footer {
  background: var(--carbon-black);
  color: #aaa;
  padding: 48px 0 24px;
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  margin-bottom: 32px;
}
.footer-col h4 {
  color: var(--white);
  font-size: 16px;
  margin-bottom: 16px;
  font-weight: 700;
}
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 8px; }
.footer-col ul li a { color: #aaa; font-size: 14px; }
.footer-col ul li a:hover { color: var(--racing-red); }
.footer-col p { font-size: 13px; line-height: 1.6; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.1);
  padding-top: 20px;
  text-align: center;
  font-size: 13px;
}
.footer-logo { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; }
.footer-logo img { height: 32px; }
.footer-logo span { color: var(--white); font-size: 18px; font-weight: 700; }

/* ---- Page Hero (Inner Pages) ---- */
.page-hero {
  background: linear-gradient(135deg, var(--carbon-black), var(--metal-gray));
  padding: 60px 0;
  text-align: center;
  color: var(--white);
}
.page-hero h1 { font-size: 36px; font-weight: 800; margin-bottom: 12px; }
.page-hero p { font-size: 16px; opacity: .8; }

/* ---- Content Cards (Inner Pages) ---- */
.content-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.content-card {
  background: var(--white);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0,0,0,.06);
  transition: all .3s;
}
.content-card:hover { transform: translateY(-4px); }
.content-card .card-body { padding: 18px; }
.content-card h3 { font-size: 16px; font-weight: 700; margin-bottom: 8px; }
.content-card p { font-size: 13px; color: var(--silver); line-height: 1.6; }

/* ---- Responsive ---- */
@media (max-width: 1024px) {
  .video-grid { grid-template-columns: repeat(2, 1fr); }
  .service-grid { grid-template-columns: repeat(2, 1fr); }
  .ai-grid { grid-template-columns: repeat(2, 1fr); }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .howto-steps { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .content-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .nav-menu { 
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--carbon-black);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
  }
  .nav-menu.active { display: flex; }
  .mobile-toggle { display: block; }
  
  .hero-banner { height: 400px; }
  .hero-content h1 { font-size: 28px; }
  .hero-content p { font-size: 15px; }
  
  .video-grid { grid-template-columns: repeat(2, 1fr); gap: 14px; }
  .service-grid { grid-template-columns: 1fr; }
  .ai-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .community-features { grid-template-columns: 1fr; }
  .howto-steps { grid-template-columns: 1fr; }
  .review-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .content-grid { grid-template-columns: 1fr; }
  
  .section { padding: 40px 0; }
  .section-title h2 { font-size: 24px; }
  .page-hero h1 { font-size: 26px; }
  .share-bar { flex-wrap: wrap; }
}

@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: 1fr; }
  .qrcode-group { flex-direction: column; align-items: center; }
}