/* ============================================
   LAYOUT — App Shell, Header, Sidebar
   ============================================ */

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ---- Header ---- */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6);
  height: 60px;
  min-height: 60px;
  background: var(--surface-primary);
  border-bottom: 1px solid var(--border-primary);
  z-index: var(--z-sticky);
  transition: background-color var(--transition-slow), border-color var(--transition-slow);
}

.header__left {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.header__logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.header__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: 1rem;
}

.header__separator {
  width: 1px;
  height: 24px;
  background: var(--border-primary);
}

.header__breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.header__breadcrumb-active {
  color: var(--text-primary);
  font-weight: 500;
}

.header__center {
  flex: 1;
  display: flex;
  justify-content: center;
  max-width: 480px;
  margin: 0 var(--space-6);
}

.header__search {
  width: 100%;
  position: relative;
}

.header__search-input {
  width: 100%;
  height: 36px;
  padding: 0 var(--space-4) 0 36px;
  background: var(--bg-tertiary);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.8125rem;
  font-family: inherit;
  transition: all var(--transition-fast);
}

.header__search-input::placeholder {
  color: var(--text-tertiary);
}

.header__search-input:hover {
  background: var(--bg-hover);
}

.header__search-input:focus {
  outline: none;
  background: var(--surface-primary);
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-muted);
}

.header__search-icon {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-tertiary);
  pointer-events: none;
  width: 16px;
  height: 16px;
}

.header__right {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* ---- Toolbar (below header) ---- */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-6);
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-secondary);
  transition: background-color var(--transition-slow), border-color var(--transition-slow);
}

.toolbar__left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.toolbar__right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* ---- Board Container ---- */
.board {
  flex: 1;
  overflow-x: auto;
  overflow-y: hidden;
  padding: var(--space-5) var(--space-6);
  background: var(--bg-primary);
  transition: background-color var(--transition-slow);
  /* Smooth horizontal scroll snap */
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
}

.board__columns {
  display: flex;
  gap: var(--column-gap);
  height: 100%;
  align-items: flex-start;
}

/* ---- Mobile ---- */
@media (max-width: 768px) {
  .header {
    padding: 0 var(--space-4);
  }

  .header__center {
    display: none;
  }

  .header__separator,
  .header__breadcrumb {
    display: none;
  }

  .toolbar {
    padding: var(--space-2) var(--space-4);
    overflow-x: auto;
  }

  .board {
    padding: var(--space-3) var(--space-4);
    scroll-snap-type: x mandatory;
  }

  .board__columns {
    gap: var(--space-4);
  }
}