:root {
  --color-primary: #1A56DB;
  --color-primary-hover: #1E40AF;
  --color-emphasis: #E85D04;
  --color-emphasis-hover: #C24A00;
  --color-success: #059669;
  --color-warm: #F59E0B;
  --color-neutral-title: #111827;
  --color-neutral-body: #4B5563;
  --color-neutral-secondary: #9CA3AF;
  --color-neutral-bg: #F9FAFB;
  --color-neutral-card: #FFFFFF;
  --color-neutral-border: #E5E7EB;

  --shadow-card: 0px 1px 3px rgba(0,0,0,0.1), 0px 1px 2px rgba(0,0,0,0.06);
  --shadow-card-hover: 0px 10px 15px rgba(0,0,0,0.1), 0px 4px 6px rgba(0,0,0,0.05);
  --shadow-nav: 0px 1px 3px rgba(0,0,0,0.05);
  --shadow-modal: rgba(0,0,0,0.5);

  --radius-btn: 8px;
  --radius-card: 12px;
  --radius-lg: 16px;

  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-2xl: 64px;
  --spacing-3xl: 80px;

  --font-hero: 48px;
  --font-h2: 32px;
  --font-card-title: 20px;
  --font-body: 16px;
  --font-number: 36px;
  --font-btn: 16px;

  --max-width-desktop: 1200px;
  --max-width-tablet: 960px;
  --max-width-mobile: 720px;
}

* {
  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;
  font-size: var(--font-body);
  line-height: 1.5;
  color: var(--color-neutral-body);
  background-color: var(--color-neutral-bg);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--color-primary-hover);
}

img {
  max-width: 100%;
  height: auto;
  loading: lazy;
}

.container {
  max-width: var(--max-width-desktop);
  margin: 0 auto;
  padding: 0 var(--spacing-2xl);
}

@media (max-width: 1365px) {
  .container {
    max-width: var(--max-width-tablet);
    padding: 0 var(--spacing-xl);
  }
}

@media (max-width: 1023px) {
  .container {
    max-width: var(--max-width-mobile);
    padding: 0 var(--spacing-md);
  }
}

@media (max-width: 767px) {
  .container {
    padding: 0 var(--spacing-sm);
  }
}

.h1 { font-size: var(--font-hero); font-weight: 700; line-height: 1.2; color: var(--color-neutral-title); }
.h2 { font-size: var(--font-h2); font-weight: 700; line-height: 1.25; color: var(--color-neutral-title); }
.h3 { font-size: var(--font-card-title); font-weight: 600; line-height: 1.4; color: var(--color-neutral-title); }

@media (max-width: 767px) {
  .h1 { font-size: 32px; }
  .h2 { font-size: 24px; }
  .h3 { font-size: 18px; }
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-size: var(--font-btn);
  font-weight: 500;
  border-radius: var(--radius-btn);
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  min-height: 44px;
  min-width: 44px;
}

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

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

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

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

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

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

.card {
  background: var(--color-neutral-card);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  padding: var(--spacing-md);
  transition: box-shadow 0.2s;
}

.card:hover {
  box-shadow: var(--shadow-card-hover);
}

/* 带图片的卡片样式 */
.card-with-image {
  padding: 0;
  overflow: hidden;
}

.card-image {
  width: 100%;
  height: 180px;
  object-fit: cover;
  display: block;
}

.card-content {
  padding: var(--spacing-md);
}

/* 教师头像样式 */
.teacher-avatar {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto var(--spacing-sm);
  display: block;
  border: 3px solid var(--color-primary);
}

/* 企业Logo样式 */
.company-logo {
  width: 100px;
  height: 100px;
  object-fit: contain;
  opacity: 0.8;
  transition: opacity 0.3s, transform 0.3s;
  filter: grayscale(30%);
}

.company-logo:hover {
  opacity: 1;
  transform: scale(1.1);
  filter: grayscale(0%);
}

/* 大图样式 */
.section-banner {
  width: 100%;
  height: 300px;
  object-fit: cover;
  border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-xl);
}

.header {
  background: var(--color-neutral-card);
  box-shadow: var(--shadow-nav);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) 0;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.logo-text {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-primary);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.nav-link {
  color: var(--color-neutral-body);
  font-weight: 500;
  padding: var(--spacing-xs) 0;
  position: relative;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width 0.2s;
}

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

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  padding: var(--spacing-xs);
  min-height: 44px;
  min-width: 44px;
}

@media (max-width: 1023px) {
  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-neutral-card);
    flex-direction: column;
    padding: var(--spacing-md);
    gap: var(--spacing-sm);
    box-shadow: var(--shadow-card);
  }

  .nav.active {
    display: flex;
  }

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

.footer {
  background: var(--color-neutral-title);
  color: white;
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

@media (max-width: 1023px) {
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 767px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

.footer-col h4 {
  color: white;
  font-size: 18px;
  margin-bottom: var(--spacing-sm);
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: var(--spacing-xs);
}

.footer-col a {
  color: var(--color-neutral-secondary);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-neutral-body);
  padding-top: var(--spacing-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.footer-contact p {
  color: var(--color-neutral-secondary);
  margin-bottom: var(--spacing-xs);
}

.floating-bar {
  position: fixed;
  right: var(--spacing-md);
  bottom: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  z-index: 90;
}

@media (max-width: 767px) {
  .floating-bar {
    display: none;
  }
}

.floating-item {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
  box-shadow: var(--shadow-card);
}

.floating-item:hover {
  background: var(--color-primary-hover);
  transform: scale(1.1);
}

.mobile-fixed-bar {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: white;
  box-shadow: 0 -1px 3px rgba(0,0,0,0.1);
  padding: var(--spacing-xs) var(--spacing-sm);
  z-index: 90;
}

@media (max-width: 767px) {
  .mobile-fixed-bar {
    display: flex;
    justify-content: space-around;
  }
}

.mobile-fixed-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--color-neutral-body);
  font-size: 12px;
  text-decoration: none;
  padding: var(--spacing-xs);
  min-width: 44px;
  min-height: 44px;
  justify-content: center;
}

.mobile-fixed-item:hover {
  color: var(--color-primary);
}

.mobile-fixed-item span {
  font-size: 20px;
}

.hero {
  background: linear-gradient(180deg, #EFF6FF 0%, #F9FAFB 100%);
  padding: var(--spacing-3xl) 0;
  text-align: center;
}

.hero h1 {
  margin-bottom: var(--spacing-sm);
}

.hero-subtitle {
  font-size: 20px;
  color: var(--color-neutral-body);
  margin-bottom: var(--spacing-xl);
}

@media (max-width: 767px) {
  .hero {
    padding: var(--spacing-xl) 0;
  }
  .hero-subtitle {
    font-size: 16px;
  }
}

.section {
  padding: var(--spacing-3xl) 0;
}

@media (max-width: 767px) {
  .section {
    padding: var(--spacing-xl) 0;
  }
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.section-header h2 {
  margin-bottom: var(--spacing-sm);
}

.section-header p {
  color: var(--color-neutral-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-lg);
}

@media (max-width: 1023px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 767px) {
  .grid-4, .grid-3, .grid-2 {
    grid-template-columns: 1fr;
  }
}

.badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: var(--radius-btn);
  font-size: 12px;
  font-weight: 500;
}

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

.badge-warm {
  background: var(--color-warm);
  color: white;
}

.badge-success {
  background: var(--color-success);
  color: white;
}

.badge-emphasis {
  background: var(--color-emphasis);
  color: white;
}

.tag {
  display: inline-block;
  padding: 4px 8px;
  border: 1px solid var(--color-neutral-border);
  border-radius: 4px;
  font-size: 12px;
  color: var(--color-neutral-secondary);
}

.form-group {
  margin-bottom: var(--spacing-sm);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
  color: var(--color-neutral-title);
}

.form-input {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--color-neutral-border);
  border-radius: var(--radius-btn);
  font-size: var(--font-body);
  transition: border-color 0.2s;
  min-height: 44px;
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.form-select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--color-neutral-border);
  border-radius: var(--radius-btn);
  font-size: var(--font-body);
  background: white;
  cursor: pointer;
  min-height: 44px;
}

.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: 14px;
  color: var(--color-neutral-secondary);
  margin-bottom: var(--spacing-md);
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--color-neutral-secondary);
}

.breadcrumb a:hover {
  color: var(--color-primary);
}

.breadcrumb span {
  color: var(--color-neutral-title);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-md);
}

@media (max-width: 1023px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 767px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
  }
}

.stat-card {
  text-align: center;
  padding: var(--spacing-md);
}

.stat-number {
  font-size: var(--font-number);
  font-weight: 700;
  color: var(--color-success);
  line-height: 1.2;
}

.stat-label {
  color: var(--color-neutral-secondary);
  font-size: 14px;
  margin-top: var(--spacing-xs);
}

.timeline {
  position: relative;
  padding-left: var(--spacing-xl);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-primary);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--spacing-lg);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: calc(-1 * var(--spacing-xl) - 5px);
  top: 4px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 2px solid white;
}

.timeline-item h4 {
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
}

.timeline-item p {
  color: var(--color-neutral-body);
  font-size: 14px;
}

.tab-nav {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  border-bottom: 2px solid var(--color-neutral-border);
  flex-wrap: wrap;
}

.tab-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  background: none;
  border: none;
  font-size: var(--font-body);
  font-weight: 500;
  color: var(--color-neutral-body);
  cursor: pointer;
  position: relative;
  min-height: 44px;
}

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

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

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

.tab-content {
  display: none;
}

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

.countdown {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--color-warm);
  color: white;
  border-radius: var(--radius-btn);
  font-weight: 500;
}

.progress-bar {
  height: 8px;
  background: var(--color-neutral-border);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--color-success);
  border-radius: 4px;
  transition: width 0.3s;
}

.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--shadow-modal);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: white;
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  max-width: 480px;
  width: 90%;
  position: relative;
  transform: scale(0.9);
  transition: transform 0.3s;
}

.modal-overlay.active .modal {
  transform: scale(1);
}

.modal-close {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  color: var(--color-neutral-secondary);
  min-width: 44px;
  min-height: 44px;
}

.modal-close:hover {
  color: var(--color-neutral-title);
}

.modal h3 {
  margin-bottom: var(--spacing-sm);
}

.modal p {
  color: var(--color-neutral-body);
  margin-bottom: var(--spacing-md);
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

@media (max-width: 767px) {
  .hide-mobile { display: none !important; }
}

@media (min-width: 768px) {
  .show-mobile-only { display: none !important; }
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

.animate-fade-in-up {
  animation: fadeInUp 0.6s ease-out;
}

@keyframes countUp {
  from { opacity: 0; }
  to { opacity: 1; }
}

.animate-count {
  animation: countUp 0.5s ease-out;
}