/* ===== Layout ===== */
body {
  font-family: 'Pretendard', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-secondary);
  color: var(--text-primary);
  transition: background var(--transition-slow), color var(--transition-slow);
}

/* ===== App Shell ===== */
#app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ===== Header ===== */
#header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  padding: 0 16px;
  gap: 12px;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  white-space: nowrap;
}

.header-logo .logo-icon {
  width: 32px;
  height: 32px;
  background: var(--accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 16px;
  flex-shrink: 0;
}

.header-logo .logo-text {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-primary);
}

.header-logo .logo-sub {
  font-size: 11px;
  font-weight: 400;
  color: var(--text-secondary);
}

.header-spacer {
  flex: 1;
}

.header-search {
  flex: 1;
  max-width: 320px;
  position: relative;
}

.header-search input {
  width: 100%;
  height: 36px;
  padding: 0 36px 0 12px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  font-size: 13px;
  color: var(--text-primary);
  outline: none;
  transition: border-color var(--transition), background var(--transition);
}

.header-search input:focus {
  border-color: var(--border-focus);
  background: var(--bg-primary);
}

.header-search input::placeholder {
  color: var(--text-muted);
}

.header-search .search-icon {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
  font-size: 14px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.btn-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 16px;
  transition: background var(--transition), color var(--transition);
}

.btn-icon:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

#btn-hamburger {
  display: none;
}

/* ===== Body Layout ===== */
#body-wrapper {
  display: flex;
  flex: 1;
  position: relative;
  padding-bottom: var(--ad-anchor-height);
}

/* ===== Ad: Left Sticky ===== */
.ad-side-left,
.ad-side-right {
  width: var(--ad-side-width);
  flex-shrink: 0;
  padding: 16px 8px;
}

.ad-sticky {
  position: sticky;
  top: calc(var(--header-height) + 16px);
}

/* ===== Main Wrapper (Sidebar + Content) ===== */
#main-wrapper {
  flex: 1;
  display: flex;
  min-width: 0;
  max-width: 1120px;
  margin: 0 auto;
  width: 100%;
}

/* ===== Sidebar ===== */
#sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  height: calc(100vh - var(--header-height));
  position: sticky;
  top: var(--header-height);
  padding: 12px 0;
  transition: background var(--transition-slow), border-color var(--transition-slow);
}

.sidebar-section {
  margin-bottom: 4px;
}

.sidebar-category {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  user-select: none;
  transition: background var(--transition), color var(--transition);
  border-radius: 0;
}

.sidebar-category:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.sidebar-category.active {
  color: var(--accent);
}

.sidebar-category .cat-icon {
  width: 20px;
  height: 20px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  flex-shrink: 0;
}

.sidebar-category .cat-label {
  flex: 1;
  letter-spacing: -0.01em;
}

.sidebar-category .cat-arrow {
  font-size: 10px;
  color: var(--text-muted);
  transition: transform var(--transition);
}

.sidebar-category.open .cat-arrow {
  transform: rotate(90deg);
}

.sidebar-items {
  overflow: hidden;
  max-height: 0;
  transition: max-height 300ms ease;
}

.sidebar-items.open {
  max-height: 600px;
}

.sidebar-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px 8px 44px;
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background var(--transition), color var(--transition);
  position: relative;
}

.sidebar-item::before {
  content: '';
  position: absolute;
  left: 28px;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--border-strong);
  transition: background var(--transition);
}

.sidebar-item:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.sidebar-item:hover::before {
  background: var(--accent);
}

.sidebar-item.active {
  background: var(--bg-active);
  color: var(--accent);
  font-weight: 600;
}

.sidebar-item.active::before {
  background: var(--accent);
}

.sidebar-item .item-badge {
  margin-left: auto;
  font-size: 10px;
  padding: 1px 6px;
  border-radius: var(--radius-full);
  background: var(--accent-light);
  color: var(--accent);
  font-weight: 500;
}

.sidebar-divider {
  height: 1px;
  background: var(--border);
  margin: 8px 16px;
}

/* ===== Main Content ===== */
#main-content {
  flex: 1;
  min-width: 0;
  background: var(--bg-primary);
  display: flex;
  flex-direction: column;
  transition: background var(--transition-slow);
}

/* ===== Tab Bar ===== */
.tab-bar {
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--border);
  background: var(--bg-primary);
  padding: 0 20px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  gap: 0;
  flex-shrink: 0;
}

.tab-bar::-webkit-scrollbar {
  display: none;
}

.tab-item {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 14px 16px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: color var(--transition), border-color var(--transition);
  flex-shrink: 0;
}

.tab-item:hover {
  color: var(--text-primary);
}

.tab-item.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
  font-weight: 600;
}

/* ===== Ad Banner: Between Tab and Calculator ===== */
.ad-banner-content {
  padding: 8px 20px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: center;
  align-items: center;
}

/* ===== Calculator Area ===== */
.calculator-area {
  flex: 1;
  padding: 24px 20px;
  overflow-y: auto;
}

.calculator-view {
  display: none;
}

.calculator-view.active {
  display: block;
}

/* Calculator Grid: Input + Result */
.calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  max-width: 900px;
}

/* ===== Welcome Screen ===== */
.welcome-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 400px;
  text-align: center;
  padding: 40px;
}

.welcome-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.welcome-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.welcome-desc {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 400px;
  margin-bottom: 32px;
}

.welcome-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
  width: 100%;
  max-width: 600px;
}

.welcome-card {
  padding: 16px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition);
  text-align: center;
}

.welcome-card:hover {
  border-color: var(--accent-border);
  background: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.welcome-card .wc-icon {
  font-size: 24px;
  margin-bottom: 8px;
}

.welcome-card .wc-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
}

.welcome-card .wc-count {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
}

.welcome-popular {
  margin-top: 32px;
  text-align: center;
}

.welcome-quick-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.quick-link {
  display: inline-block;
  padding: 8px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 13px;
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.15s;
  text-decoration: none;
}

.quick-link:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

/* Share button in action bar */
.btn-share {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* ===== Sidebar Overlay (Mobile) ===== */
#sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 199;
}

#sidebar-overlay.visible {
  display: block;
}

/* ===== Ad: Bottom Anchor ===== */
#ad-anchor {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 200;
  background: var(--bg-primary);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: center;
  align-items: center;
  height: var(--ad-anchor-height);
  padding: 0 16px;
}

#ad-anchor .anchor-close {
  position: absolute;
  top: -10px;
  right: 12px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 10px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background var(--transition);
}

#ad-anchor .anchor-close:hover {
  background: var(--danger-light);
  color: var(--danger);
}

#ad-anchor.hidden {
  display: none;
}

/* ===== Interstitial Ad ===== */
#interstitial-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

#interstitial-overlay.visible {
  display: flex;
}

.interstitial-box {
  background: var(--bg-primary);
  border-radius: var(--radius-xl);
  padding: 24px;
  width: 90%;
  max-width: 400px;
  position: relative;
  box-shadow: var(--shadow-xl);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.interstitial-close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition);
}

.interstitial-close:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.interstitial-close:not(:disabled):hover {
  background: var(--danger-light);
  color: var(--danger);
}

.interstitial-label {
  font-size: 11px;
  color: var(--text-muted);
}

.interstitial-countdown {
  font-size: 12px;
  color: var(--text-secondary);
  text-align: center;
}