/* 基础样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', system-ui, sans-serif;
}

body {
  background-color: #f9fafb;
  color: #1f2937;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

a {
  text-decoration: none;
  color: inherit;
}

button {
  border: none;
  background: none;
  cursor: pointer;
}

/* 导航栏样式 */
header {
  background-color: white;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 50;
  transition: all 0.3s ease;
  padding: 1rem 0;
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo-icon {
  color: #3B82F6;
  font-size: 1.5rem;
}

.logo-text {
  font-size: 1.25rem;
  font-weight: bold;
  color: #1E293B;
}

.nav-links {
  display: none;
  gap: 2rem;
  align-items: center;
}

.nav-links a {
  color: #4B5563;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: #3B82F6;
}

.auth-buttons {
  display: none;
  gap: 1rem;
}

.login-btn {
  padding: 0.5rem 1.25rem;
  border: 1px solid #3B82F6;
  border-radius: 0.5rem;
  color: #3B82F6;
  transition: background-color 0.2s;
}

.login-btn:hover {
  background-color: rgba(59, 130, 246, 0.05);
}

.register-btn {
  padding: 0.5rem 1.25rem;
  border-radius: 0.5rem;
  background-color: #3B82F6;
  color: white;
  transition: background-color 0.2s;
}

.register-btn:hover {
  background-color: rgba(59, 130, 246, 0.9);
}

.menu-btn {
  display: block;
  color: #4B5563;
  font-size: 1.5rem;
}

.mobile-menu {
  display: none;
  background-color: white;
  border-top: 1px solid #e5e7eb;
  margin-top: 1rem;
  padding: 1rem 0;
}

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

.mobile-links {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 1rem 0;
}

.mobile-links a {
  color: #4B5563;
  padding: 0.5rem 0;
  transition: color 0.2s;
}

.mobile-links a:hover {
  color: #3B82F6;
}

.mobile-auth {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding-top: 1rem;
  margin-top: 1rem;
  border-top: 1px solid #e5e7eb;
}

/* 英雄区域样式 */
.hero {
  position: relative;
  background: linear-gradient(135deg, #eff6ff 0%, #ecfdf5 100%);
  padding: 5rem 0;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0.1;
  overflow: hidden;
}

.hero-circle {
  position: absolute;
  width: 24rem;
  height: 24rem;
  border-radius: 50%;
}

.circle-blue {
  background-color: #3B82F6;
  right: -6rem;
  top: -6rem;
}

.circle-green {
  background-color: #10B981;
  left: -6rem;
  bottom: -6rem;
}

.hero-content {
  position: relative;
  z-index: 10;
  text-align: center;
  max-width: 36rem;
  margin: 0 auto;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: bold;
  color: #1E293B;
  margin-bottom: 1.5rem;
  text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.hero-desc {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: #6B7280;
  margin-bottom: 2.5rem;
  max-width: 28rem;
  margin-left: auto;
  margin-right: auto;
}

.hero-buttons {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  justify-content: center;
  margin-bottom: 3rem;
}

@media (min-width: 640px) {
  .hero-buttons {
    flex-direction: row;
  }
}

.hero-btn {
  padding: 0.75rem 2rem;
  border-radius: 0.5rem;
  font-weight: 500;
  transition: all 0.3s ease;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.hero-btn:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
}

.primary-btn {
  background-color: #3B82F6;
  color: white;
}

.primary-btn:hover {
  background-color: rgba(59, 130, 246, 0.9);
}

.secondary-btn {
  background-color: white;
  color: #3B82F6;
  border: 1px solid #3B82F6;
}

.secondary-btn:hover {
  background-color: #f9fafb;
}

.user-count {
  color: #6B7280;
  font-size: 0.875rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.user-count strong {
  color: #3B82F6;
}

/* 功能特点样式 */
.features {
  padding: 5rem 0;
  background-color: white;
}

.section-header {
  text-align: center;
  margin-bottom: 4rem;
}

.section-title {
  font-size: clamp(1.5rem, 3vw, 2.5rem);
  font-weight: bold;
  color: #1E293B;
  margin-bottom: 1rem;
}

.section-desc {
  color: #6B7280;
  max-width: 28rem;
  margin: 0 auto;
}

.features-grid {
  display: grid;
  gap: 2rem;
}

@media (min-width: 768px) {
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature-card {
  background-color: #f9fafb;
  border-radius: 0.75rem;
  padding: 2rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  transition: box-shadow 0.2s;
}

.feature-card:hover {
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.feature-icon {
  width: 3.5rem;
  height: 3.5rem;
  border-radius: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
  font-size: 2rem;
}

.icon-blue {
  background-color: #dbeafe;
  color: #3B82F6;
}

.icon-green {
  background-color: #d1fae5;
  color: #10B981;
}

.icon-purple {
  background-color: #e0e7ff;
  color: #7c3aed;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.feature-desc {
  color: #6B7280;
}

/* 关于我们样式 */
.about {
  padding: 5rem 0;
  background-color: #f9fafb;
}

.about-content {
  display: flex;
  flex-direction: column;
  gap: 3rem;
}

@media (min-width: 768px) {
  .about-content {
    flex-direction: row;
    align-items: center;
  }
}

.about-image {
  width: 100%;
  border-radius: 0.75rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

@media (min-width: 768px) {
  .about-image {
    width: 50%;
  }
}

.about-text {
  width: 100%;
}

@media (min-width: 768px) {
  .about-text {
    width: 50%;
  }
}

.about-desc {
  color: #6B7280;
  margin-bottom: 1rem;
}

.about-features {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.5rem;
}

.about-feature {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: #1E293B;
}

.about-feature i {
  color: #10B981;
}

/* 联系我们样式 */
.contact {
  padding: 5rem 0;
  background-color: white;
}

.contact-form {
  max-width: 28rem;
  margin: 0 auto;
  background-color: #f9fafb;
  border-radius: 0.75rem;
  padding: 2rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.form-group {
  margin-bottom: 1rem;
}

.form-label {
  display: block;
  color: #4B5563;
  margin-bottom: 0.5rem;
}

.form-input, .form-textarea {
  width: 100%;
  padding: 0.5rem 1rem;
  border: 1px solid #d1d5db;
  border-radius: 0.5rem;
  transition: all 0.2s;
}

.form-input:focus, .form-textarea:focus {
  outline: none;
  border-color: #3B82F6;
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.25);
}

.form-textarea {
  min-height: 100px;
  resize: vertical;
}

.submit-btn {
  width: 100%;
  padding: 0.75rem;
  border-radius: 0.5rem;
  background-color: #3B82F6;
  color: white;
  font-weight: 500;
  transition: background-color 0.2s;
}

.submit-btn:hover {
  background-color: rgba(59, 130, 246, 0.9);
}

/* 页脚样式 */
footer {
  background-color: #1E293B;
  color: #94a3b8;
  padding: 3rem 0;
}

.footer-grid {
  display: grid;
  gap: 2rem;
  margin-bottom: 2rem;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.footer-col h4 {
  color: white;
  font-weight: 600;
  margin-bottom: 1rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-links a {
  color: #94a3b8;
  transition: color 0.2s;
}

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

.social-links {
  display: flex;
  gap: 1rem;
  margin-top: 1rem;
}

.social-links a {
  color: #94a3b8;
  transition: color 0.2s;
}

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

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}

.contact-item i {
  color: #3B82F6;
  margin-top: 0.25rem;
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  margin-top: 2rem;
  border-top: 1px solid #334155;
  font-size: 0.875rem;
  color: #64748b;
}

/* 响应式调整 */
@media (min-width: 768px) {
  .nav-links {
    display: flex;
  }
  
  .auth-buttons {
    display: flex;
  }
  
  .menu-btn {
    display: none;
  }
}