:root {
  --stu-primary: var(--color-primary, #007AFF);
  --stu-bg: var(--color-background, #F2F2F7);
  --stu-sidebar-bg: #ffffff;
  --stu-text: var(--color-text, #000000);
  
  /* Original Gradient kept as requested */
  --stu-gradient: linear-gradient(135deg, #66a6ff 0%, #89f7fe 100%);
}

body {
  background-color: var(--stu-bg);
  color: var(--stu-text);
  font-family: "Noto Sans TC", "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

.navbar-stu {
  background-color: var(--stu-sidebar-bg);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.navbar-brand {
  font-weight: 600;
  color: var(--stu-primary) !important;
}

.main-header {
  background: var(--stu-gradient);
  color: white;
  padding: 3rem 0;
  margin: 15px;
  border-radius: var(--radius-xl, 30px);
  box-shadow: var(--shadow-md, 0 8px 32px rgba(0, 0, 0, 0.08));
  position: relative;
  overflow: hidden;
}

.main-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(5px);
  pointer-events: none;
  z-index: 1; /* Match container if needed, but we used relative on container */
}

/* Ensure container is always on top of blur */
.main-header .container {
  position: relative;
  z-index: 10;
}

.page-title {
  font-weight: 700;
  margin-bottom: 0.5rem;
  font-size: 2rem;
  text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.2);
}

.user-info {
  font-size: 1.1rem;
  opacity: 0.9;
}

.main-content {
  background-color: var(--color-card, #fff);
  border-radius: var(--radius-lg, 20px);
  box-shadow: var(--shadow-soft, 0 4px 24px rgba(0, 0, 0, 0.04));
  padding: 2rem;
  margin-bottom: 2rem;
  min-height: 60vh;
  border: 1px solid rgba(0,0,0,0.02);
}

.footer {
  padding: 2rem 0;
  margin-top: auto;
  color: var(--color-text-muted, #8E8E93);
}

@media (max-width: 767.98px) {
  .main-header {
    margin: 1rem;
    padding: 1rem 0;
  }

  .main-header .container {
    padding-inline: 1rem;
  }

  .header-content {
    gap: 0.5rem 0;
  }

  .main-header .header-content > img {
    height: 48px !important;
  }

  .header-content > .flex-grow-1 {
    min-width: 0;
    overflow-wrap: anywhere;
  }

  .page-title {
    font-size: 1.25rem;
  }

  .user-info {
    font-size: 1rem;
  }

  .main-content {
    padding: 1rem;
  }

  .main-content > #app.container {
    padding-inline: 0;
  }
}