/* =========================
   레이아웃 (헤더, 푸터, 메인)
========================= */

/* ===== 상단 헤더 ===== */
.top-header {
  background-color: var(--color-bg-white);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  will-change: transform;
  transform: translateZ(0);
  backface-visibility: hidden;
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: var(--spacing-2xl);
  flex-wrap: wrap;
}

.logo {
  font-size: clamp(18px, 4vw, 22px);
  font-weight: var(--font-weight-extrabold);
  color: var(--color-text);
  white-space: nowrap;
}

/* ===== 메인 네비게이션 ===== */
.main-nav {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.main-nav a {
  position: relative;
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-semibold);
  font-size: clamp(0.85rem, 3vw, 1rem);
  padding-bottom: 1px;
  transition: color var(--transition-slow);
  white-space: nowrap;
}

.main-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -6px;
  width: 100%;
  height: 2px;
  background-color: var(--color-primary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--transition-slow);
}

.main-nav a:hover {
  color: var(--color-primary);
}

.main-nav a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.main-nav a.active {
  color: var(--color-primary);
}

.main-nav a.active::after {
  transform: scaleX(1);
}

/* ===== 2차 네비게이션 (하위 탭) ===== */
.sub-header {
  background-color: var(--color-bg-white);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 54px; /* 헤더 높이만큼 */
  z-index: calc(var(--z-sticky) - 1);
  will-change: transform;
  transform: translateZ(0);
  backface-visibility: hidden;
}

.sub-header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  gap: var(--spacing-xl);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

/* 모바일에서 스크롤바 숨기기 */
.sub-header-inner::-webkit-scrollbar {
  display: none;
}

.sub-header-inner a {
  position: relative;
  padding: 14px 0;
  color: var(--color-text-light);
  font-weight: var(--font-weight-semibold);
  font-size: clamp(0.85rem, 3vw, 1rem);
  transition: color var(--transition-slow);
  white-space: nowrap;
  flex-shrink: 0;
}

.sub-header-inner a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-primary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--transition-slow);
}

.sub-header-inner a:hover {
  color: var(--color-primary);
}

.sub-header-inner a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.sub-header-inner a.active {
  color: var(--color-primary);
}

.sub-header-inner a.active::after {
  transform: scaleX(1);
}

/* ===== 메인 콘텐츠 영역 ===== */
.page {
  flex: 1;
  max-width: var(--max-width);
  margin: 30px auto;
  padding: 0 20px;
  width: 100%;
  box-sizing: border-box;
}

.content-area {
  background-color: var(--color-bg-white);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-lg);
  max-width: 100%;
  width: 100%;
  box-sizing: border-box;
  transition: all 0.3s ease;
  min-height: auto;
}

.content-title {
  font-size: clamp(16px, 4vw, 20px);
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
}

.tab-content {
  font-size: clamp(12px, 3vw, 14px);
  color: var(--color-text-secondary);
  min-height: auto;
}

/* ===== 푸터 ===== */
.footer {
  text-align: center;
  padding: var(--spacing-xl);
  font-size: clamp(11px, 2.5vw, 13px);
  color: var(--color-text-muted);
  background-color: var(--color-bg-white);
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

/* ===== 반응형 ===== */
@media (max-width: 768px) {
  .header-inner {
    gap: var(--spacing-lg);
    padding: 12px 16px;
  }

  .main-nav {
    gap: 16px;
  }

  .sub-header {
    top: 50px;
  }

  .sub-header-inner {
    gap: var(--spacing-lg);
    padding: 0 16px;
  }

  .sub-header-inner a {
    padding: 12px 0;
  }

  .page {
    margin: 16px auto;
    padding: 0 12px;
  }

  .content-area {
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-md);
  }
}

@media (max-width: 480px) {
  .header-inner {
    gap: var(--spacing-md);
    padding: 10px 12px;
    flex-wrap: nowrap;
    justify-content: space-between;
  }

  .main-nav {
    gap: 10px;
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    -ms-overflow-style: none;
  }

  .main-nav::-webkit-scrollbar {
    display: none;
  }

  .sub-header {
    top: 44px;
  }

  .sub-header-inner {
    gap: var(--spacing-md);
    padding: 0 12px;
  }

  .sub-header-inner a {
    padding: 10px 0;
  }

  .page {
    margin: 12px auto;
    padding: 0 8px;
  }

  .content-area {
    padding: var(--spacing-md);
    border-radius: var(--border-radius-sm);
  }

  .footer {
    padding: var(--spacing-lg);
  }
}

/* 매우 작은 화면 */
@media (max-width: 360px) {
  .header-inner {
    padding: 8px 10px;
  }

  .main-nav {
    gap: 8px;
  }

  .sub-header-inner {
    gap: var(--spacing-sm);
    padding: 0 10px;
  }

  .page {
    padding: 0 6px;
  }

  .content-area {
    padding: var(--spacing-sm);
  }
}