/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 52px;
  background: rgba(255, 255, 255, 0.8);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-nav);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
}

.nav__logo {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text-primary);
  white-space: nowrap;
}

.nav__logo span {
  color: var(--color-accent);
}

.nav__links {
  display: flex;
  gap: 4px;
  align-items: center;
}

.nav__link {
  font-size: 14px;
  color: var(--color-text-secondary);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
  white-space: nowrap;
}

.nav__link:hover {
  color: var(--color-text-primary);
  background: var(--color-bg-secondary);
}

.nav__link.is-active {
  color: var(--color-accent);
  font-weight: 500;
}

/* Hamburger (mobile) */
.nav__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  cursor: pointer;
}

.nav__hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: 2px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

/* ===== Hero ===== */
.hero {
  height: 100vh;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 52px 24px 0;
  background: var(--color-bg);
}

.hero__eyebrow {
  font-size: 48px;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  animation: fadeInUp 0.8s ease both;
}

.hero__title {
  font-size: 64px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.5px;
  color: var(--color-text-primary);
  margin-bottom: 24px;
  animation: fadeInUp 0.8s ease 0.15s both;
}

.hero__subtitle {
  font-size: 19px;
  color: var(--color-text-secondary);
  margin-bottom: 8px;
  animation: fadeInUp 0.8s ease 0.3s both;
}

.hero__stats {
  font-size: 21px;
  color: var(--color-text-secondary);
  line-height: 1.4;
  animation: fadeInUp 0.8s ease 0.45s both;
}

.hero__scroll-hint {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--color-text-tertiary);
  font-size: 14px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  animation: fadeInUp 0.8s ease 0.6s both;
}

.hero__scroll-hint::after {
  content: '';
  display: block;
  width: 1px;
  height: 40px;
  background: var(--color-border);
  animation: scrollPulse 2s ease-in-out infinite;
}

/* ===== Main Content ===== */
.main {
  padding-top: 0;
}

/* ===== Category Section ===== */
.category {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--color-border);
}

.category:first-of-type {
  border-top: none;
}

.category__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.category__header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: var(--space-xl);
}

.category__title {
  font-size: 48px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-primary);
}

.category__title-en {
  display: block;
  font-size: 21px;
  font-weight: 400;
  color: var(--color-text-tertiary);
  margin-top: 4px;
  letter-spacing: 0.01em;
}

.category__count {
  font-size: 17px;
  color: var(--color-text-tertiary);
  white-space: nowrap;
}

.category__description {
  font-size: 17px;
  color: var(--color-text-secondary);
  margin-top: 8px;
  margin-bottom: var(--space-xl);
}

/* ===== Cards Grid ===== */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

/* ===== Expand Button ===== */
.expand-btn {
  display: block;
  margin: var(--space-xl) auto 0;
  padding: 12px 32px;
  font-size: 17px;
  color: var(--color-accent);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-btn);
  background: transparent;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.expand-btn:hover {
  background: var(--color-bg-secondary);
  border-color: var(--color-accent);
}

.expand-btn.is-hidden {
  display: none;
}

/* ===== Footer ===== */
.footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--space-xl) 0;
  margin-top: var(--space-2xl);
}

.footer__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 14px;
  line-height: 2;
}

.footer__inner a {
  color: var(--color-accent);
}

.footer__inner a:hover {
  color: var(--color-accent-hover);
}

/* ===== Animations ===== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scrollPulse {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 1; }
}

/* ===== Error State ===== */
.error-state {
  text-align: center;
  padding: 120px 24px;
  color: var(--color-text-secondary);
}

.error-state__icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.error-state__text {
  font-size: 21px;
  margin-bottom: 24px;
}

.error-retry-btn {
  padding: 12px 32px;
  font-size: 17px;
  color: var(--color-accent);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-btn);
  background: transparent;
  cursor: pointer;
  font-family: var(--font-family);
}

.error-retry-btn:hover {
  background: var(--color-accent-light);
}