/* ============================================
   Components: 按钮、卡片、导航、页脚、徽章等
   ============================================ */

/* ====== Buttons ====== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: var(--text-sm);
  line-height: 1;
  padding: var(--space-3) var(--space-5);
  border: 2px solid transparent;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
  user-select: none;
}

.btn:active {
  transform: scale(0.97);
}

/* Keyboard focus ring */
.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--color-primary) 20%, transparent);
}

/* Primary */
.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-primary);
  box-shadow: 0 4px 14px rgb(124 58 237 / 0.3);
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  box-shadow: 0 6px 20px rgb(124 58 237 / 0.4);
  transform: translateY(-1px);
}

.btn-primary:active {
  background: var(--color-primary-active);
  box-shadow: 0 2px 8px rgb(124 58 237 / 0.3);
  transform: translateY(0) scale(0.97);
}

/* Secondary */
.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-bg-alt);
  border-color: var(--color-text-muted);
  transform: translateY(-1px);
}

.btn-secondary:active {
  background: var(--color-border);
  transform: translateY(0) scale(0.97);
}

/* Ghost */
.btn-ghost {
  background: transparent;
  color: var(--color-text-secondary);
  border-color: transparent;
}

.btn-ghost:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
}

/* Sizes */
.btn-sm {
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-xs);
  border-radius: var(--radius-md);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
  border-radius: var(--radius-xl);
  gap: var(--space-3);
}

.btn svg {
  transition: transform var(--transition-fast);
}

.btn:hover svg {
  transform: translateX(3px);
}

/* ====== Loading Spinner State ====== */
/* Add class "is-loading" to show spinner and disable interaction */
.btn.is-loading {
  position: relative;
  pointer-events: none;
  cursor: default;
  color: transparent !important;
  gap: 0;
}

.btn.is-loading svg {
  opacity: 0;
  transform: none;
}

/* Spinner via pseudo-element — uses explicit color, not currentColor */
.btn.is-loading::after {
  content: '';
  position: absolute;
  width: 18px;
  height: 18px;
  border: 2px solid;
  border-radius: 50%;
  animation: btn-spin 0.6s linear infinite;
}

.btn-primary.is-loading::after {
  border-color: rgba(255,255,255,0.6);
  border-top-color: #ffffff;
}

.btn-secondary.is-loading::after,
.btn-ghost.is-loading::after {
  border-color: rgba(100,116,139,0.4);
  border-top-color: var(--color-text-secondary);
}

.btn-sm.is-loading::after {
  width: 14px;
  height: 14px;
  border-width: 2px;
}

.btn-lg.is-loading::after {
  width: 22px;
  height: 22px;
  border-width: 2.5px;
}

@keyframes btn-spin {
  to { transform: rotate(360deg); }
}

/* ====== Card ====== */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: all var(--transition-base);
}

.card:hover {
  border-color: var(--color-primary-light);
  box-shadow: 0 0 0 1px var(--color-primary-light), var(--shadow-glow);
  transform: translateY(-3px);
}

.card:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ====== Navigation ====== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background: var(--color-bg);
}

/* Mobile nav backdrop overlay */
.nav-overlay {
  position: fixed;
  inset: 0;
  top: var(--header-height);
  z-index: 98;
  background: rgba(0, 0, 0, 0.4);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
  -webkit-backdrop-filter: blur(2px);
  backdrop-filter: blur(2px);
}

.nav-overlay.is-visible {
  opacity: 1;
  pointer-events: auto;
}

[data-theme="dark"] .nav-overlay {
  background: rgba(0, 0, 0, 0.6);
}

@media (prefers-reduced-transparency: no-preference) {
  .site-header {
    background: color-mix(in srgb, var(--color-bg) 85%, transparent);
  }
}

.nav-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
  height: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* Logo */
.nav-brand {
  flex-shrink: 0;
}

/* Desktop: nav links centered */
.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex: 1;
  justify-content: center;
}

/* Theme toggle on the right */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: var(--space-1);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.theme-toggle:hover {
  color: var(--color-text);
  background: var(--color-bg-alt);
  border-color: var(--color-text-muted);
}

.theme-toggle:focus-visible,
.nav-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.theme-toggle .sun-icon { display: block; }
.theme-toggle .moon-icon { display: none; }

[data-theme="dark"] .theme-toggle .sun-icon { display: none; }
[data-theme="dark"] .theme-toggle .moon-icon { display: block; }

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  font-weight: 800;
  font-size: var(--text-xl);
  color: var(--color-text);
}

.logo-icon {
  font-size: 1.6em;
  line-height: 1;
  transition: transform var(--transition-base);
}

.nav-logo:hover .logo-icon {
  transform: scale(1.1) rotate(-10deg);
}

.logo-text {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Desktop nav links */
.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  position: relative;
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  text-decoration: none;
}

.nav-link:hover {
  color: var(--color-text);
  background: var(--color-bg-alt);
}

.nav-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.nav-link.active {
  color: var(--color-primary);
  font-weight: 600;
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 3px;
  background: var(--color-primary);
  border-radius: var(--radius-full);
  animation: nav-indicator-in 0.4s ease both;
}

@keyframes nav-indicator-in {
  from {
    width: 0;
    opacity: 0;
  }
  to {
    width: 20px;
    opacity: 1;
  }
}

/* ====== Navigation Link ====== */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: var(--space-2);
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 101;
}

.hamburger-line {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-text);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
  transform-origin: center;
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ====== Footer ====== */
.site-footer {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding: var(--space-16) 0 var(--space-8);
  margin-top: var(--space-16);
}

.footer-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.footer-brand {
  margin-bottom: var(--space-8);
}

.footer-brand .logo-icon {
  font-size: 1.4em;
}

.footer-brand .logo-text {
  font-size: var(--text-xl);
  font-weight: 800;
}

.footer-subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
}

.footer-links {
  display: flex;
  gap: var(--space-12);
  margin-bottom: var(--space-10);
  flex-wrap: wrap;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-heading {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-1);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-link {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
  text-decoration: none;
}

.footer-link:hover {
  color: var(--color-primary);
}

.footer-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.footer-bottom {
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
  text-align: center;
}

.footer-bottom p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}

.footer-disclaimer {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  max-width: 600px;
  margin: var(--space-3) auto 0;
  line-height: 1.6;
}

/* ====== Badge ====== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  background: var(--color-primary-bg);
  color: var(--color-primary);
}

.badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-primary);
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

/* ====== Tag/Tag ====== */
.test-tag {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  background: color-mix(in srgb, var(--tag-color, #7c3aed) 15%, transparent);
  color: var(--tag-color, #7c3aed);
}

/* ====== Hero Section ====== */
.hero-section {
  position: relative;
  padding: var(--space-20) 0 var(--space-16);
  text-align: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 50% 0%, var(--color-primary-bg) 0%, transparent 60%);
  z-index: 0;
  overflow: hidden;
}

/* Subtle breathing aura overlay */
.hero-bg::after {
  content: '';
  position: absolute;
  inset: -50%;
  background: radial-gradient(ellipse at 50% 30%, var(--color-primary-light) 0%, transparent 50%);
  opacity: 0;
  animation: hero-aura 8s ease-in-out infinite;
  pointer-events: none;
}

@keyframes hero-aura {
  0%, 100% { opacity: 0; transform: scale(0.8); }
  50% { opacity: 0.3; transform: scale(1.15); }
}

[data-theme="dark"] .hero-bg {
  background: radial-gradient(ellipse at 50% 0%, var(--color-primary-bg) 0%, transparent 60%);
}

[data-theme="dark"] .hero-bg::after {
  background: radial-gradient(ellipse at 50% 30%, var(--color-primary-lighter) 0%, transparent 50%);
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  font-weight: 600;
  border-radius: var(--radius-full);
  background: var(--color-primary-bg);
  color: var(--color-primary);
  border: 1px solid var(--color-primary-lighter);
  margin-bottom: var(--space-6);
}

.hero-title {
  font-size: var(--text-5xl);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-6);
  background: linear-gradient(135deg, var(--color-text), var(--color-primary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-8);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  margin-bottom: var(--space-12);
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-10);
  flex-wrap: wrap;
}

.stat-item {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: var(--text-4xl);
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: var(--space-1);
}

.stat-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: 500;
}

/* ====== Features Section ====== */
.features-section {
  padding: var(--space-16) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-12);
  padding: 0 var(--space-6);
}

.section-title {
  font-size: var(--text-3xl);
  font-weight: 800;
  margin-bottom: var(--space-3);
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 48px;
  height: 3px;
  border-radius: var(--radius-full);
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  opacity: 0.6;
}

.section-desc {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  max-width: 500px;
  margin: 0 auto;
  margin-top: var(--space-5);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.feature-card {
  text-align: center;
  padding: var(--space-8) var(--space-6);
}

.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: var(--radius-xl);
  background: color-mix(in srgb, var(--icon-color, #7c3aed) 12%, transparent);
  color: var(--icon-color, #7c3aed);
  margin-bottom: var(--space-5);
  transition: all var(--transition-base);
}

.feature-card:hover .feature-icon {
  transform: scale(1.1);
  box-shadow: 0 0 30px color-mix(in srgb, var(--icon-color, #7c3aed) 25%, transparent);
}

.feature-title {
  font-size: var(--text-xl);
  font-weight: 700;
  margin-bottom: var(--space-2);
}

.feature-desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ====== Tests Section ====== */
.tests-section {
  padding: var(--space-16) 0;
  background: var(--color-bg-alt);
}

.tests-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.test-card {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: inherit;
  transition: all var(--transition-base);
}

.test-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-3);
}

.test-duration {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: 500;
}

.test-card-title {
  font-size: var(--text-lg);
  font-weight: 700;
  margin-bottom: var(--space-2);
  line-height: 1.3;
  transition: color var(--transition-base);
}

.test-card:hover .test-card-title {
  color: var(--color-primary);
}

.test-card-desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: var(--space-4);
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.test-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-border-light);
}

.test-questions {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: 500;
}

.test-arrow {
  color: var(--color-primary);
  opacity: 0.5;
  transform: translateX(-3px);
  transition: all var(--transition-base);
}

.test-card:hover .test-arrow,
.test-card:focus-visible .test-arrow {
  opacity: 1;
  transform: translateX(3px);
}

.section-actions {
  text-align: center;
  margin-top: var(--space-8);
}

/* ====== CTA Section ====== */
.cta-section {
  padding: var(--space-20) 0;
  text-align: center;
  background: linear-gradient(135deg, var(--color-primary-bg) 0%, var(--color-bg) 50%, var(--color-primary-bg) 100%);
  background-size: 200% 200%;
  animation: cta-gradient-shift 12s ease-in-out infinite alternate;
}

@keyframes cta-gradient-shift {
  0% { background-position: 0% 0%; }
  100% { background-position: 100% 100%; }
}

/* CTA content scales subtly on hover */
.cta-section:hover .cta-content {
  transform: scale(1.01);
}

.cta-content {
  max-width: 600px;
  margin: 0 auto;
  padding: 0 var(--space-6);
  transition: transform var(--transition-slow);
}

.cta-title {
  font-size: var(--text-3xl);
  font-weight: 800;
  margin-bottom: var(--space-4);
}

.cta-desc {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-8);
}

/* ====== Page Header ====== */
.page-header {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: var(--space-12) var(--space-6) var(--space-8);
  text-align: center;
}

.page-tag {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  background: color-mix(in srgb, var(--tag-color, #7c3aed) 15%, transparent);
  color: var(--tag-color, #7c3aed);
  margin-bottom: var(--space-4);
}

.page-title {
  font-size: var(--text-4xl);
  font-weight: 800;
  margin-bottom: var(--space-3);
}

.page-subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  max-width: 500px;
  margin: 0 auto;
}

.page-content {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 0 var(--space-6) var(--space-16);
}

/* ====== Listing Page ====== */
.listing-page {
  padding: 0 0 var(--space-16);
}

.listing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.section-content {
  max-width: var(--container-narrow);
  margin: var(--space-10) auto 0;
  padding: 0 var(--space-6);
}

/* ====== Empty State ====== */
.empty-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--space-12) var(--space-6);
}

.empty-icon {
  font-size: 3rem;
  margin-bottom: var(--space-4);
}

.empty-state h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-2);
}

.empty-state p {
  color: var(--color-text-muted);
}

/* ====== Language Switcher ====== */
.lang-switch {
  font-weight: 700 !important;
  font-size: var(--text-sm) !important;
  padding: var(--space-1) var(--space-3) !important;
  border: 1px solid var(--color-primary) !important;
  border-radius: var(--radius-full) !important;
  color: var(--color-primary) !important;
  margin-left: var(--space-2) !important;
}
.lang-switch:hover {
  background: var(--color-primary) !important;
  color: white !important;
}