/* ===== 三端架构 ===== */

.three-end {
  padding: var(--section-padding-y) 0;
  background: white;
  position: relative;
}

.three-end-visual {
  margin-top: 64px;
  position: relative;
  display: flex;
  justify-content: center;
}

.three-end-img-wrapper {
  width: 100%;
  max-width: 900px;
  position: relative;
}

.three-end-img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-xl);
  box-shadow: 0 32px 64px rgba(30, 64, 175, 0.12);
}

/* 三端卡片网格 */
.three-end-cards {
  margin-top: 64px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.three-end-card {
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  transition: all 0.3s ease;
}

.three-end-card:hover {
  border-color: var(--brand-300);
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.three-end-card-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--brand-100), var(--brand-50));
  color: var(--brand-700);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  flex-shrink: 0;
}

.three-end-card-tag {
  display: inline-block;
  padding: 4px 10px;
  background: var(--brand-50);
  color: var(--brand-700);
  font-size: 12px;
  font-weight: 500;
  border-radius: 6px;
  margin-bottom: 12px;
  align-self: flex-start;
}

.three-end-card-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 10px;
}

.three-end-card-desc {
  font-size: 14px;
  color: var(--gray-500);
  line-height: 1.7;
  margin-bottom: 20px;
}

.three-end-card-features {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: auto;
}

.three-end-card-features li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14px;
  color: var(--gray-700);
  line-height: 1.5;
  margin: 0;
  padding: 0;
}

.three-end-card-check {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  color: var(--brand-500);
  margin-top: 3px;
}

.three-end-card-check svg {
  width: 16px;
  height: 16px;
  display: block;
}

.three-end-card-features li span {
  flex: 1;
  display: block;
  white-space: normal;
  word-break: normal;
  text-align: left;
  line-height: 1.6;
  writing-mode: horizontal-tb;
  direction: ltr;
}

/* 架构关系线 */
.three-end-diagram {
  display: none;
  margin-top: 48px;
  padding: 40px;
  background: linear-gradient(135deg, var(--brand-50), #f0f9ff);
  border-radius: var(--radius-xl);
}

@media (max-width: 860px) {
  .three-end-cards {
    grid-template-columns: 1fr;
    max-width: 480px;
    margin-left: auto;
    margin-right: auto;
  }
}

/* ===== 核心功能 ===== */

.features {
  padding: var(--section-padding-y) 0;
  background: var(--bg-cream);
  position: relative;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.feature-card {
  padding: 28px 24px;
  background: white;
  border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200);
  transition: all 0.3s ease;
  cursor: default;
}

.feature-card:hover {
  border-color: var(--brand-300);
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
}

.feature-card.featured {
  background: linear-gradient(135deg, var(--brand-700), var(--brand-900));
  color: white;
  border-color: transparent;
  grid-column: span 2;
}

.feature-card.featured:hover {
  box-shadow: 0 20px 40px rgba(30, 64, 175, 0.3);
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--brand-50);
  color: var(--brand-600);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  transition: all 0.3s ease;
}

.feature-card:hover .feature-icon {
  background: var(--brand-100);
  color: var(--brand-700);
  transform: scale(1.05);
}

.feature-card.featured .feature-icon {
  background: rgba(255, 255, 255, 0.15);
  color: white;
}

.feature-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.feature-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--gray-900);
}

.feature-card.featured .feature-title {
  color: white;
  font-size: 20px;
  font-weight: 700;
}

.feature-tag {
  display: inline-block;
  padding: 3px 8px;
  background: var(--brand-50);
  color: var(--brand-600);
  font-size: 11px;
  font-weight: 500;
  border-radius: 4px;
  white-space: nowrap;
}

.feature-card.featured .feature-tag {
  background: rgba(255, 255, 255, 0.2);
  color: white;
}

.feature-desc {
  font-size: 13px;
  color: var(--gray-500);
  line-height: 1.6;
}

.feature-card.featured .feature-desc {
  color: rgba(255, 255, 255, 0.8);
  font-size: 14px;
  line-height: 1.7;
}

@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .feature-card.featured {
    grid-column: span 2;
  }
}

@media (max-width: 480px) {
  .features-grid {
    grid-template-columns: 1fr;
  }
  .feature-card.featured {
    grid-column: span 1;
  }
}

/* ===== 通用区块头 ===== */

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto;
}

.section-title {
  font-size: 36px;
  font-weight: 700;
  color: var(--gray-900);
  margin-top: 16px;
  margin-bottom: 16px;
  line-height: 1.3;
}

.section-subtitle {
  font-size: 17px;
  color: var(--gray-500);
  line-height: 1.7;
}

/* 淡入动画 */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}