* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', 'Arial', sans-serif;
}

body {
  background: #fafafa;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 20px;
}

/* 顶部 Logo 和标语 */
.header {
  text-align: center;
  margin-bottom: 40px;
}

.logo {
  font-size: 28px;
  font-weight: 700;
  color: #2d2d2d;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.logo i {
  color: #2563eb;
}

.slogan {
  color: #6b7280;
  font-size: 16px;
  margin-top: 8px;
}

/* 主内容 */
.container {
  max-width: 900px;
  width: 100%;
}

/* 输入卡片 */
.input-card {
  background: #ffffff;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  margin-bottom: 30px;
}

.input-card h2 {
  color: #2d2d2d;
  font-size: 28px;
  font-weight: 600;
  margin-bottom: 12px;
}

.input-card p {
  color: #6b7280;
  font-size: 14px;
  margin-bottom: 24px;
}

.input-group {
  margin-bottom: 16px;
}

#longUrl {
  width: 100%;
  padding: 12px;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  font-size: 14px;
  color: #2d2d2d;
  background: #f9fafb;
}

#longUrl:focus {
  outline: none;
  border-color: #2563eb;
  background: #ffffff;
}

.dropdown, .password-input {
  margin-bottom: 16px;
}

#expirySelect, #password {
  width: 100%;
  padding: 12px;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  font-size: 14px;
  color: #2d2d2d;
  background: #f9fafb;
}

#expirySelect:focus, #password:focus {
  outline: none;
  border-color: #2563eb;
  background: #ffffff;
}

.password-input {
  position: relative;
}

.eye-icon {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  cursor: pointer;
  color: #6b7280;
}

.generate-btn {
  background: #2563eb;
  color: #ffffff;
  border: none;
  padding: 14px;
  border-radius: 8px;
  cursor: pointer;
  width: 100%;
  font-size: 16px;
  font-weight: 500;
  transition: background 0.2s;
}

.generate-btn:hover {
  background: #3b82f6;
}

/* 生成结果 */
.result-section {
  background: #ffffff;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  margin-bottom: 30px;
}

.result-section h3 {
  color: #2d2d2d;
  font-size: 20px;
  font-weight: 500;
  margin-bottom: 12px;
}

.result-section p {
  color: #6b7280;
  font-size: 14px;
  margin-bottom: 8px;
  line-height: 1.5;
}

.copy-btn {
  background: #f3f4f6;
  border: none;
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 12px;
  color: #2d2d2d;
  transition: background 0.2s;
}

.copy-btn:hover {
  background: #e5e7eb;
}

/* 功能介绍卡片 */
.features-section {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-bottom: 40px;
}

.feature-card {
  background: #ffffff;
  padding: 24px;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  text-align: left;
  transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.feature-card i {
  font-size: 24px;
  color: #2563eb;
  margin-bottom: 12px;
}

.feature-card h3 {
  color: #2d2d2d;
  font-size: 18px;
  font-weight: 500;
  margin-bottom: 8px;
}

.feature-card p {
  color: #6b7280;
  font-size: 14px;
  line-height: 1.6;
}

/* 使用步骤 */
.steps-section {
  margin-bottom: 40px;
}

.steps-section h2 {
  color: #2d2d2d;
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 24px;
  text-align: center;
}

.steps {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.step {
  display: flex;
  align-items: center;
  gap: 16px;
  background: #ffffff;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.step-number {
  width: 40px;
  height: 40px;
  background: #2563eb;
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 500;
}

.step h3 {
  color: #2d2d2d;
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 4px;
}

.step p {
  color: #6b7280;
  font-size: 14px;
  line-height: 1.5;
}

/* 常见问题 */
.faq-section {
  margin-bottom: 40px;
}

.faq-section h2 {
  color: #2d2d2d;
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 24px;
  text-align: center;
}

.faq-item {
  background: #ffffff;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  margin-bottom: 16px;
}

.faq-item h3 {
  color: #2d2d2d;
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 8px;
}

.faq-item p {
  color: #6b7280;
  font-size: 14px;
  line-height: 1.5;
}

/* 底部 */
footer {
  text-align: center;
  padding: 30px;
  color: #9ca3af;
  font-size: 12px;
}

/* 隐藏类 */
.hidden {
  display: none;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .container {
    padding: 0 10px;
  }

  .input-card, .result-section, .feature-card, .step, .faq-item {
    padding: 20px;
  }

  .input-card h2, .steps-section h2, .faq-section h2 {
    font-size: 24px;
  }

  .result-section h3 {
    font-size: 18px;
  }

  .feature-card h3, .step h3, .faq-item h3 {
    font-size: 16px;
  }

  .features-section {
    grid-template-columns: 1fr;
  }

  .step {
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
  }
}

/* 验证页面卡片 */
.verify-card {
  background: #ffffff;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  margin-bottom: 30px;
  text-align: center;
}

.verify-card h2 {
  color: #2d2d2d;
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 12px;
}

.verify-card p {
  color: #6b7280;
  font-size: 14px;
  margin-bottom: 24px;
}

.error-message {
  color: #ef4444;
  font-size: 14px;
  margin-top: 12px;
}

/* 注意提示 */
.note {
  color: #ef4444;
  font-size: 12px;
  margin-top: 12px;
  font-style: italic;
}