:root {
  --background-color: #f5f7fb;
  --card-background: #ffffff;
  --primary-color: #2f54eb;
  --primary-color-dark: #1d39c4;
  --text-color: #1f2933;
  --muted-text-color: #52616b;
  --border-radius: 16px;
  --shadow-color: rgba(15, 23, 42, 0.12);
  --max-content-width: 1080px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: linear-gradient(180deg, #eef2f7 0%, #f7f9fc 100%);
  color: var(--text-color);
  min-height: 100vh;
}

.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.app-header {
  background: var(--card-background);
  box-shadow: 0 12px 30px var(--shadow-color);
  padding: 24px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 10;
}

.branding h1 {
  margin: 0;
  font-size: 28px;
  color: var(--primary-color);
}

.branding .tagline {
  margin: 4px 0 0;
  color: var(--muted-text-color);
  font-size: 14px;
}

.actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.primary-button {
  border: none;
  background: var(--primary-color);
  color: #fff;
  padding: 10px 20px;
  font-size: 14px;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.2s ease;
}

.primary-button:hover {
  background: var(--primary-color-dark);
  transform: translateY(-1px);
}

.primary-button:focus {
  outline: 2px solid rgba(47, 84, 235, 0.4);
  outline-offset: 2px;
}

.user-info {
  font-size: 14px;
  color: var(--muted-text-color);
}

.app-main {
  flex: 1;
  width: 100%;
  display: flex;
  justify-content: center;
  padding: 32px 16px 64px;
}

.navigation-section,
.message-section {
  width: 100%;
  max-width: var(--max-content-width);
}

.message-section {
  background: var(--card-background);
  border-radius: var(--border-radius);
  box-shadow: 0 18px 40px var(--shadow-color);
  padding: 48px;
  text-align: center;
}

.message-section h2 {
  margin: 0 0 12px;
  font-size: 24px;
  color: var(--primary-color);
}

.message-section p {
  margin: 0 0 24px;
  color: var(--muted-text-color);
  line-height: 1.6;
}

.navigation-container {
  display: grid;
  gap: 24px;
}

.category-card {
  background: var(--card-background);
  border-radius: var(--border-radius);
  padding: 28px;
  box-shadow: 0 18px 40px var(--shadow-color);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.category-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.category-header h2 {
  margin: 0;
  font-size: 20px;
  color: var(--primary-color);
}

.category-header span {
  font-size: 13px;
  color: var(--muted-text-color);
}

.link-list {
  display: grid;
  gap: 12px;
}

.link-item {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 16px;
  border-radius: 12px;
  border: 1px solid rgba(47, 84, 235, 0.08);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.link-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 24px rgba(47, 84, 235, 0.12);
}

.link-details h3 {
  margin: 0 0 4px;
  font-size: 16px;
}

.link-details p {
  margin: 0;
  font-size: 13px;
  color: var(--muted-text-color);
  line-height: 1.5;
}

.link-action a {
  text-decoration: none;
  color: var(--primary-color);
  font-weight: 600;
}

.hidden {
  display: none;
}

.app-footer {
  text-align: center;
  padding: 32px 16px;
  color: var(--muted-text-color);
  font-size: 12px;
  background-color: rgba(255, 255, 255, 0.9);
  border-top: 1px solid rgba(47, 84, 235, 0.1);
}

.footer-content {
  max-width: var(--max-content-width);
  margin: 0 auto;
}

.footer-sections {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 32px;
  margin: 24px 0;
}

.footer-section {
  flex: 1;
  min-width: 300px;
  max-width: 400px;
  padding: 24px;
  background-color: rgba(47, 84, 235, 0.03);
  border-radius: var(--border-radius);
  text-align: left;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.04);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.footer-section:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.08);
}

.footer-title {
  color: var(--primary-color);
  font-size: 16px;
  margin: 0 0 16px 0;
  font-weight: 600;
  padding-bottom: 8px;
  border-bottom: 2px solid rgba(47, 84, 235, 0.2);
}

.company-brief {
  margin: 0;
  line-height: 1.6;
}

.company-address,
.company-phone {
  margin: 8px 0;
  line-height: 1.5;
}

.company-info p {
  margin: 0 0 12px 0;
}

.company-info p:last-child {
  margin-bottom: 0;
}

.about-section {
  background-color: rgba(47, 84, 235, 0.03);
}

.contact-section {
  background-color: rgba(47, 84, 235, 0.02);
}

@media (max-width: 768px) {
  .footer-sections {
    flex-direction: column;
    gap: 16px;
  }
  
  .footer-section {
    min-width: 100%;
    max-width: 100%;
  }
}

@media (min-width: 768px) {
  .navigation-container {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1200px) {
  .navigation-container {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 600px) {
  .app-header {
    align-items: flex-start;
    gap: 16px;
  }

  .primary-button {
    width: 100%;
  }

  .link-item {
    flex-direction: column;
    align-items: flex-start;
  }

  .link-action {
    width: 100%;
  }

  .link-action a {
    display: inline-block;
    margin-top: 8px;
  }
}