/* ===== 基础重置 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --blue: #0066ff;
  --blue-dark: #0044cc;
  --orange: #ff7700;
  --red: #e53935;
  --text: #333;
  --text-light: #666;
  --text-muted: #999;
  --border: #e8e8e8;
  --bg-gray: #f5f5f5;
  --container: 1200px;
}

body {
  font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: #fff;
  line-height: 1.6;
  min-width: 1200px;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

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

/* ===== 顶部工具栏 ===== */
.top-bar {
  background: #f7f7f7;
  border-bottom: 1px solid var(--border);
  font-size: 12px;
  color: var(--text-light);
}

.top-bar-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 32px;
}

.top-bar-left span { margin-right: 12px; }
.top-bar-left a,
.top-bar-right a {
  color: var(--text-light);
  margin-left: 12px;
  transition: color .2s;
}
.top-bar-left a:hover,
.top-bar-right a:hover { color: var(--blue); }

.auth-guest a,
.auth-user a { margin-left: 12px; }
.auth-username {
  color: var(--blue);
  margin-right: 4px;
}

.hidden { display: none !important; }

/* ===== 主导航 ===== */
.main-header {
  background: #fff;
  box-shadow: 0 1px 4px rgba(0,0,0,.06);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.logo { display: flex; align-items: center; gap: 10px; }
.logo img { height: 50px; }
.logo-fallback { display: none; align-items: center; gap: 8px; }
.logo-icon {
  background: linear-gradient(135deg, #ff9900, #0066ff);
  color: #fff;
  font-weight: bold;
  padding: 6px 10px;
  border-radius: 4px;
  font-size: 14px;
}
.logo-text { font-size: 13px; color: var(--text); font-weight: 600; max-width: 180px; line-height: 1.3; }

.main-nav { display: flex; gap: 0; }
.main-nav a {
  padding: 0 14px;
  font-size: 14px;
  color: var(--text-light);
  line-height: 70px;
  position: relative;
  white-space: nowrap;
  transition: color .2s;
}
.main-nav a:hover,
.main-nav a.active { color: var(--blue); }
.main-nav a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 14px;
  right: 14px;
  height: 3px;
  background: var(--blue);
}

/* ===== 轮播横幅 ===== */
.hero-carousel {
  position: relative;
  height: 420px;
  overflow: hidden;
}

.carousel-track { height: 100%; position: relative; }

.carousel-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity .6s;
  pointer-events: none;
}
.carousel-slide.active { opacity: 1; pointer-events: auto; }

.slide-1 {
  background: linear-gradient(135deg, #0033aa 0%, #0055ff 40%, #0077ff 100%);
  overflow: hidden;
}
.slide-1::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60%;
  height: 120px;
  background: linear-gradient(90deg, #00cc66, #ffcc00);
  clip-path: ellipse(80% 100% at 20% 100%);
  opacity: .7;
}
.slide-1::after {
  content: '';
  position: absolute;
  bottom: 0;
  right: 0;
  width: 200px;
  height: 100px;
  background:
    repeating-linear-gradient(45deg, #ff9900 0 8px, transparent 8px 16px),
    repeating-linear-gradient(-45deg, #0066ff 0 8px, transparent 8px 16px);
  opacity: .4;
}

.slide-content {
  display: flex;
  align-items: center;
  height: 100%;
  position: relative;
  z-index: 2;
  padding-top: 20px;
}

.slide-badge {
  color: rgba(255,255,255,.8);
  font-size: 13px;
  margin-bottom: 10px;
}

.slide-number {
  font-size: 120px;
  font-weight: 100;
  color: rgba(255,255,255,.25);
  line-height: 1;
  letter-spacing: -8px;
  font-family: "Arial Narrow", sans-serif;
}
.slide-number .th { font-size: 24px; vertical-align: super; letter-spacing: 0; }

.slide-center { flex: 1; padding-left: 30px; }
.slide-tagline {
  font-size: 22px;
  color: #ffcc00;
  margin-bottom: 8px;
  font-weight: 600;
}
.slide-center h1 {
  font-size: 36px;
  color: #fff;
  font-weight: 700;
  margin-bottom: 10px;
  text-shadow: 0 2px 8px rgba(0,0,0,.2);
}
.slide-sub {
  font-size: 13px;
  color: rgba(255,255,255,.7);
  letter-spacing: 1px;
}

.slide-mascot {
  font-size: 80px;
  opacity: .6;
  filter: grayscale(1) brightness(3);
}

.slide-slogan {
  position: absolute;
  bottom: 30px;
  left: 0;
  right: 0;
  text-align: center;
  color: rgba(255,255,255,.6);
  font-size: 13px;
  letter-spacing: 2px;
  z-index: 2;
}

.slide-2 {
  background: linear-gradient(rgba(0,20,80,.7), rgba(0,20,80,.7)),
    url('images/hero-2.jpg') center/cover;
  background-color: #001a66;
}
.slide-3 {
  background: linear-gradient(rgba(0,0,0,.5), rgba(0,0,0,.5)),
    url('images/hero-3.jpg') center/cover;
  background-color: #1a1a2e;
}
.slide-4 {
  background: linear-gradient(rgba(0,40,100,.6), rgba(0,40,100,.6)),
    url('images/hero-4.jpg') center/cover;
  background-color: #002266;
}

.slide-overlay {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  text-align: center;
  color: #fff;
}
.slide-overlay h2 { font-size: 48px; font-weight: 700; margin-bottom: 16px; }
.slide-overlay .year { font-size: 36px; margin-bottom: 20px; }
.slide-link { font-size: 16px; color: #fff; opacity: .9; }
.slide-link:hover { opacity: 1; text-decoration: underline; }

.carousel-dots {
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 10;
}
.carousel-dots .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 2px solid rgba(255,255,255,.6);
  background: transparent;
  cursor: pointer;
  padding: 0;
  transition: all .3s;
}
.carousel-dots .dot.active {
  background: #fff;
  border-color: #fff;
  transform: scale(1.2);
}

/* ===== 公告新闻 ===== */
.news-section { padding: 40px 0; }

.news-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 30px;
}

.featured-panel { position: relative; }

.featured-carousel {
  position: relative;
  border-radius: 4px;
  overflow: hidden;
  height: 320px;
}
.featured-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity .5s;
}
.featured-slide.active { opacity: 1; z-index: 1; }
.featured-slide img { width: 100%; height: 100%; object-fit: cover; }
.featured-slide .featured-caption { position: absolute; }

.featured-dots {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 12px;
}
.featured-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: none;
  background: #ccc;
  cursor: pointer;
  padding: 0;
}
.featured-dot.active { background: var(--blue); }

.featured-img {
  position: relative;
  border-radius: 4px;
  overflow: hidden;
  height: 320px;
}
.featured-img img { width: 100%; height: 100%; object-fit: cover; }
#featured-news .featured-img img { object-fit: contain; background: #f8f8f8; }
.featured-img.placeholder {
  background: linear-gradient(135deg, #1565c0, #42a5f5);
}
.featured-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(0,0,0,.6);
  color: #fff;
  padding: 12px 16px;
  font-size: 14px;
}

.news-tabs { display: flex; gap: 24px; margin-bottom: 20px; border-bottom: 1px solid var(--border); }
.tab-btn {
  background: none;
  border: none;
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
  padding: 0 0 12px;
  cursor: pointer;
  position: relative;
}
.tab-btn.active { color: var(--blue); }
.tab-btn.active::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--blue);
}

.news-list li {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 14px 0;
  border-bottom: 1px dashed var(--border);
  gap: 16px;
}
.news-list li.important a { color: var(--red); }
.news-list li a {
  flex: 1;
  font-size: 14px;
  color: var(--text);
  line-height: 1.5;
  transition: color .2s;
}
.news-list li a:hover { color: var(--blue); }

.date-box {
  text-align: center;
  min-width: 50px;
  flex-shrink: 0;
}
.date-box .day {
  display: block;
  font-size: 22px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.2;
}
.date-box .ym {
  display: block;
  font-size: 11px;
  color: var(--text-muted);
}

.news-list.hidden { display: none; }

.featured-slide-link {
  display: block;
  width: 100%;
  height: 100%;
  position: relative;
}
.featured-slide-link:hover .featured-caption { background: rgba(0, 102, 255, .75); }
a.featured-img { display: block; }
a.featured-img:hover .featured-caption { background: rgba(0, 102, 255, .75); }

.hidden { display: none !important; }

/* ===== 详情页 ===== */
.detail-page { padding: 30px 0 60px; background: var(--bg-gray); min-height: 50vh; }

.detail-breadcrumb {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 24px;
}
.detail-breadcrumb a { color: var(--text-light); }
.detail-breadcrumb a:hover { color: var(--blue); }
.detail-breadcrumb .sep { margin: 0 8px; }
.detail-breadcrumb .current { color: var(--text); }

.detail-article {
  background: #fff;
  border-radius: 6px;
  padding: 40px 48px;
  box-shadow: 0 1px 6px rgba(0,0,0,.06);
}

.detail-header { margin-bottom: 28px; padding-bottom: 20px; border-bottom: 1px solid var(--border); }
.detail-tag {
  display: inline-block;
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 3px;
  margin-bottom: 12px;
  background: #e8f0ff;
  color: var(--blue);
}
.detail-tag.news { background: #fff3e0; color: var(--orange); }
.detail-header h1 {
  font-size: 26px;
  line-height: 1.4;
  color: var(--text);
  margin-bottom: 12px;
}
.detail-date { font-size: 13px; color: var(--text-muted); }

.detail-cover {
  margin-bottom: 28px;
  border-radius: 4px;
  overflow: hidden;
  text-align: center;
  background: #f8f8f8;
}
.detail-cover img {
  max-width: 100%;
  max-height: 480px;
  margin: 0 auto;
  object-fit: contain;
}

.detail-body {
  font-size: 15px;
  line-height: 1.9;
  color: var(--text);
}
.detail-body p { margin-bottom: 16px; }
.detail-body ul {
  list-style: disc;
  margin: 0 0 16px 24px;
}
.detail-body li { margin-bottom: 8px; }
.detail-body strong { color: var(--text); }

.detail-footer { margin-top: 36px; padding-top: 24px; border-top: 1px solid var(--border); }
.detail-back {
  display: inline-block;
  font-size: 14px;
  color: var(--blue);
  transition: color .2s;
}
.detail-back:hover { color: var(--blue-dark); }

.detail-not-found {
  background: #fff;
  border-radius: 6px;
  padding: 60px 48px;
  text-align: center;
  box-shadow: 0 1px 6px rgba(0,0,0,.06);
}
.detail-not-found h2 { font-size: 22px; margin-bottom: 12px; }
.detail-not-found p { color: var(--text-light); margin-bottom: 24px; }

/* ===== 次级轮播 ===== */
.sub-carousel-section { padding: 20px 0 40px; }

.sub-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 30px;
}

.sub-slide {
  height: 220px;
  border-radius: 4px;
  overflow: hidden;
}
.sub-slide img { width: 100%; height: 100%; object-fit: cover; }
.sub-slide.placeholder-amd {
  background: linear-gradient(135deg, #0d1b2a, #1b263b, #415a77);
  display: flex;
  align-items: center;
  justify-content: center;
}
.sub-slide.placeholder-amd::after {
  content: 'AMD杯 AI+3D 创新应用大赛';
  color: #fff;
  font-size: 20px;
  font-weight: 600;
}

.sub-caption {
  margin-top: 10px;
  font-size: 14px;
  color: var(--text-light);
}

.sub-pagination {
  display: flex;
  gap: 8px;
  margin-top: 12px;
}
.sub-page {
  width: 28px;
  height: 28px;
  border: 1px solid var(--border);
  background: #fff;
  font-size: 13px;
  cursor: pointer;
  color: var(--text-light);
}
.sub-page.active {
  background: var(--blue);
  color: #fff;
  border-color: var(--blue);
}

.sub-news { position: relative; }
.sub-news .more-link {
  position: absolute;
  bottom: 0;
  right: 0;
  font-size: 13px;
  color: var(--text-muted);
}
.sub-news .more-link:hover { color: var(--blue); }

.more-link { font-size: 13px; color: var(--text-muted); white-space: nowrap; }
.more-link:hover { color: var(--blue); }

/* ===== 通用区块标题 ===== */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 24px;
}
.section-header h2 {
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
}
.section-header .en,
.section-title-center .en {
  font-size: 13px;
  color: var(--text-muted);
  margin-top: 4px;
}

.section-title-center {
  text-align: center;
  margin-bottom: 36px;
  position: relative;
}
.section-title-center::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  height: 0;
  border-top: 1px dashed #ccc;
  z-index: 0;
}
.section-title-center h2,
.section-title-center .en {
  position: relative;
  background: #fff;
  display: inline-block;
  padding: 0 24px;
  z-index: 1;
}
.section-title-center h2 { font-size: 28px; font-weight: 700; }

/* ===== 视频资料 ===== */
.video-section { padding: 40px 0; }

.video-player {
  position: relative;
  height: 400px;
  border-radius: 4px;
  overflow: hidden;
}
.video-player img { width: 100%; height: 100%; object-fit: cover; }
.video-player.placeholder-video {
  background: linear-gradient(135deg, #4a148c, #7b1fa2, #9c27b0);
}
.play-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--blue);
  color: #fff;
  border: 3px solid #fff;
  font-size: 22px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-left: 4px;
  transition: transform .2s;
}
.play-btn:hover { transform: translate(-50%, -50%) scale(1.1); }

.video-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-top: none;
  font-size: 14px;
}
.video-meta .time { font-size: 12px; color: var(--text-muted); }

/* ===== 产业应用赛项 ===== */
.events-section { padding: 40px 0 60px; }

.events-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.event-card {
  position: relative;
  height: 200px;
  border-radius: 6px;
  overflow: hidden;
  background: var(--bg, #333);
  background-image: var(--bg);
  box-shadow: 0 4px 12px rgba(0,0,0,.1);
  transition: transform .3s;
}
.event-card:hover { transform: translateY(-4px); }

.event-overlay {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(0, 80, 200, .75);
  padding: 16px 20px;
  text-align: center;
  width: 85%;
  border-radius: 4px;
}
.event-overlay p {
  color: #fff;
  font-size: 14px;
  line-height: 1.6;
  font-weight: 500;
}

.event-btn {
  position: absolute;
  bottom: 12px;
  right: 12px;
  background: var(--orange);
  color: #fff;
  font-size: 12px;
  padding: 6px 14px;
  border-radius: 20px;
  transition: background .2s;
}
.event-btn:hover { background: #e56a00; }

/* ===== 往届精彩 ===== */
.highlights-section { padding: 40px 0 60px; }

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

.highlight-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 4px;
}
.highlight-card.ph-1,
.highlight-card.ph-2,
.highlight-card.ph-3 { }
.highlight-card.ph-1::before,
.highlight-card.ph-2::before,
.highlight-card.ph-3::before {
  content: '';
  display: block;
  height: 200px;
  border-radius: 4px;
}
.highlight-card.ph-1::before { background: linear-gradient(135deg, #37474f, #607d8b); }
.highlight-card.ph-2::before { background: linear-gradient(135deg, #455a64, #78909c); }
.highlight-card.ph-3::before { background: linear-gradient(135deg, #263238, #546e7a); }

.highlight-card p {
  text-align: center;
  margin-top: 12px;
  font-size: 13px;
  color: var(--text-light);
}

/* ===== 专家风采 ===== */
.experts-section {
  padding: 60px 0;
  background: var(--bg-gray);
  overflow: hidden;
}

.experts-layout {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 40px;
  align-items: center;
}

.experts-card {
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 4px 20px rgba(0,0,0,.08);
  padding: 30px;
}

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

.expert { text-align: center; }
.expert img {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 10px;
  border: 2px solid var(--border);
}
.expert img.avatar-ph {
  background: linear-gradient(135deg, #b0bec5, #78909c);
  object-fit: none;
}
.expert h4 { font-size: 15px; margin-bottom: 6px; }
.expert p { font-size: 11px; color: var(--text-light); line-height: 1.5; }

.experts-title {
  position: relative;
  text-align: left;
  padding-left: 20px;
}
.experts-title .bg-text {
  position: absolute;
  top: -30px;
  left: -20px;
  font-size: 100px;
  font-weight: 900;
  color: rgba(0,0,0,.04);
  line-height: 1;
  pointer-events: none;
  user-select: none;
}
.experts-title h2 { font-size: 32px; font-weight: 700; margin-bottom: 6px; }
.experts-title .more-link { display: inline-block; margin-top: 30px; }

/* ===== 特别推荐 ===== */
.recommend-section { padding: 60px 0; }

.product-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.product-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 2px solid var(--orange);
  border-radius: 6px;
  overflow: hidden;
  min-height: 200px;
}

.product-info {
  background: var(--orange);
  padding: 16px;
  color: #fff;
  display: flex;
  flex-direction: column;
}
.product-info h3 {
  font-size: 15px;
  color: #000;
  margin-bottom: 10px;
}
.product-info .badge {
  background: #fff;
  color: var(--orange);
  font-size: 12px;
  padding: 8px;
  border-radius: 4px;
  text-align: center;
  margin-bottom: 12px;
  line-height: 1.4;
}
.product-info .badge strong { font-size: 22px; display: block; color: var(--orange); }
.product-info ul { font-size: 11px; color: #333; margin-top: auto; }
.product-info li { margin-bottom: 4px; }

.product-img {
  background: #fff;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}
.product-img .brand {
  position: absolute;
  top: 10px;
  right: 12px;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-muted);
}
.laptop-ph {
  width: 120px;
  height: 80px;
  background: linear-gradient(135deg, #cfd8dc, #90a4ae);
  border-radius: 4px 4px 0 0;
  position: relative;
}
.laptop-ph::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: -10px;
  right: -10px;
  height: 6px;
  background: #78909c;
  border-radius: 0 0 4px 4px;
}

/* ===== 团队风采 ===== */
.teams-section {
  padding: 60px 0;
  background: var(--bg-gray);
}

.teams-scroll {
  display: flex;
  gap: 24px;
  overflow-x: auto;
  padding: 0 calc((100% - var(--container)) / 2 + 20px) 20px;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}
.teams-scroll::-webkit-scrollbar { height: 6px; }
.teams-scroll::-webkit-scrollbar-thumb { background: #ccc; border-radius: 3px; }

.team-card {
  flex: 0 0 280px;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0,0,0,.08);
  overflow: hidden;
  scroll-snap-align: start;
}
.team-card img {
  width: 100%;
  height: 160px;
  object-fit: cover;
}
.team-card img.team-ph {
  background: linear-gradient(135deg, #546e7a, #78909c);
  object-fit: none;
}
.team-card h4 {
  padding: 14px 16px 6px;
  font-size: 14px;
}
.team-card p {
  padding: 0 16px 16px;
  font-size: 12px;
  color: var(--text-light);
  line-height: 1.7;
}

/* ===== 项目展示 ===== */
.projects-section { padding: 60px 0; }

.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.project-item {
  height: 360px;
  border-radius: 4px;
  background-size: cover;
  background-position: center;
  transition: transform .3s;
}
.project-item:hover { transform: scale(1.02); }
.ph-p1 { background: linear-gradient(135deg, #2e7d32, #66bb6a, #a5d6a7); }
.ph-p2 { background: linear-gradient(135deg, #4e342e, #8d6e63, #bcaaa4); }
.ph-p3 { background: linear-gradient(135deg, #1b5e20, #388e3c, #81c784); }

/* ===== 页脚 ===== */
.site-footer { margin-top: 40px; }

.footer-bar {
  height: 8px;
  background: var(--bg-gray);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 30px;
  padding: 50px 20px 30px;
}

.footer-col h4 {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 16px;
  color: #000;
}
.footer-col li { margin-bottom: 10px; }
.footer-col a {
  font-size: 13px;
  color: var(--text-muted);
  transition: color .2s;
}
.footer-col a:hover { color: var(--blue); }

.copyright {
  text-align: center;
  padding: 20px;
  font-size: 12px;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

/* ===== 悬浮按钮 ===== */
.float-register {
  position: fixed;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  background: #fff;
  border: 1px solid var(--blue);
  border-right: none;
  border-radius: 6px 0 0 6px;
  padding: 12px 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  z-index: 200;
  box-shadow: -2px 2px 8px rgba(0,0,0,.1);
  transition: background .2s;
}
.float-register:hover { background: #f0f6ff; }
.float-register .icon { font-size: 18px; }
.float-register .text {
  writing-mode: vertical-rl;
  font-size: 13px;
  color: var(--blue);
  letter-spacing: 4px;
}

.back-top {
  position: fixed;
  right: 20px;
  bottom: 30px;
  width: 40px;
  height: 40px;
  background: #555;
  color: #fff;
  border: none;
  font-size: 18px;
  cursor: pointer;
  z-index: 200;
  opacity: 0;
  visibility: hidden;
  transition: opacity .3s, visibility .3s;
}
.back-top.visible { opacity: 1; visibility: visible; }
.back-top:hover { background: #333; }