frontend/src/styles/app.css

/* ============================================================================
   App shell + screen layout (Section 2.0 global nav, 2.1–2.5 screens).
   MOBILE-FIRST responsive system: base styles target the smallest screens,
   then min-width breakpoints progressively enhance toward desktop.
   Covers: phones (320-480px), tablets (768-1024px), laptops, wide desktops.
   ========================================================================== */

/* ===== Base (mobile-first): designed for 320px+ ===== */
* { -webkit-tap-highlight-color: transparent; }
html { -webkit-text-size-adjust: 100%; }

.app-shell { display: flex; min-height: 100vh; min-height: 100dvh; /* dynamic viewport: accounts for mobile browser chrome */ }

/* Sidebar: drawer by default (mobile), persistent on >= md */
.sidebar {
  width: min(280px, 84vw); background: var(--color-surface); border-right: 1px solid var(--color-border);
  padding: var(--space-6) var(--space-4); display: flex; flex-direction: column; gap: var(--space-2);
  flex-shrink: 0; height: 100vh; height: 100dvh;
  /* mobile drawer state */
  position: fixed; left: 0; top: 0; z-index: 900; transform: translateX(-100%);
  transition: transform .25s ease; box-shadow: 2px 0 16px rgba(0,0,0,.18); overflow-y: auto;
}
.sidebar.open { transform: translateX(0); }
.sidebar .logo { font-size: var(--fs-fluid-md); font-weight: 800; color: var(--color-primary); margin-bottom: var(--space-6); display: flex; align-items: center; gap: var(--space-2); white-space: nowrap; }
.nav-link { display: flex; align-items: center; gap: var(--space-3); padding: var(--space-3); border-radius: var(--radius); color: var(--color-text-secondary); text-decoration: none; font-size: var(--fs-14); font-weight: 600; min-height: 44px; /* touch target a11y */ }
.nav-link:hover { background: var(--color-surface-muted); color: var(--color-text-primary); }
.nav-link.active { background: rgba(13,125,107,.1); color: var(--color-primary); }
.sidebar .spacer { flex: 1; }

.main {
  flex: 1; padding: var(--space-4); width: 100%; min-width: 0;
  max-width: 1200px; margin: 0 auto;
}
.page-title { font-size: var(--fs-fluid-xl); margin-bottom: var(--space-2); line-height: 1.15; word-break: break-word; }
.page-sub { color: var(--color-text-secondary); margin-bottom: var(--space-6); font-size: var(--fs-fluid-sm); }

/* Mobile menu button: visible by default */
.menu-toggle { display: inline-flex; }
.scrim { display: none; }
.scrim.show { display: block; position: fixed; inset: 0; background: rgba(0,0,0,.45); z-index: 800; }

/* Auth screen */
.auth-wrap { min-height: 100vh; min-height: 100dvh; display: flex; align-items: center; justify-content: center; padding: var(--space-4); }
.auth-card { width: 100%; max-width: 420px; }

/* Dashboard widgets */
.stat-card { display: flex; flex-direction: column; gap: var(--space-1); }
.stat-card .num { font-size: var(--fs-fluid-2xl); font-weight: 800; color: var(--color-primary); line-height: 1; }

/* Editor: single column by default (mobile), dual-pane on >= md */
.editor-wrap { display: grid; grid-template-columns: 1fr; gap: var(--space-5); }
.editor-pane { display: flex; flex-direction: column; gap: var(--space-3); min-width: 0; }
.preview-frame { border: 1px solid var(--color-border); border-radius: var(--radius); padding: var(--space-4); background: var(--color-on-primary); min-height: 300px; overflow: auto; max-height: 70vh; /* review HTML can wrap */ word-break: break-word; }
.json-preview { font-family: var(--font-mono); font-size: var(--fs-12); background: var(--color-code-bg); color: var(--color-code-fg); padding: var(--space-3); border-radius: var(--radius); white-space: pre-wrap; word-break: break-word; max-height: 70vh; overflow: auto; }
.code-editor { font-family: var(--font-mono); font-size: var(--fs-12); min-height: 260px; }

/* Tables: horizontally scrollable wrapper on small screens */
.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }
table.tbl { width: 100%; border-collapse: collapse; min-width: 560px; /* keeps columns usable inside scroll */ }
table.tbl th, table.tbl td { text-align: left; padding: var(--space-3) var(--space-4); border-bottom: 1px solid var(--color-border); font-size: var(--fs-14); white-space: nowrap; }
table.tbl td:first-child { white-space: normal; }

/* Export screen */
.export-row { display: grid; grid-template-columns: 1fr; gap: var(--space-2); padding: var(--space-4) 0; border-bottom: 1px solid var(--color-border); }

/* Progress bar */
.progress { height: 8px; background: var(--color-surface-muted); border-radius: 999px; overflow: hidden; }
.progress > div { height: 100%; background: var(--color-primary); transition: width .3s; }

.error-banner { background: var(--color-banner-error-bg); border: 1px solid var(--color-banner-error-border); color: var(--color-banner-error-fg); padding: var(--space-3) var(--space-4); border-radius: var(--radius); font-size: var(--fs-fluid-sm); display: flex; flex-wrap: wrap; gap: var(--space-2); align-items: center; }
.empty-state { text-align: center; padding: var(--space-8) var(--space-4); color: var(--color-text-secondary); }
.empty-state .ill { font-size: 48px; margin-bottom: var(--space-4); }

.pagination { display: flex; gap: var(--space-2); justify-content: center; align-items: center; margin-top: var(--space-6); flex-wrap: wrap; }

/* Row components stack vertically by default */
.row { display: flex; gap: var(--space-4); flex-wrap: wrap; }
.grid { display: grid; gap: var(--space-4); }

/* Responsive auto-fit grid — collapses columns based on available width
   without needing breakpoints (used for stat cards, checkbox groups). */
.grid-auto { display: grid; gap: var(--space-4); grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }
/* Two-column grid that collapses to one column under the tablet breakpoint. */
.grid-2 { display: grid; gap: var(--space-4); grid-template-columns: 1fr; }
@media (min-width: 480px) { .grid-2 { grid-template-columns: 1fr 1fr; } }

/* Campaign list row: card-like on mobile, full row on tablet+. */
.campaign-row { display: grid; grid-template-columns: 1fr; gap: var(--space-2); align-items: center; padding: var(--space-4) 0; border-bottom: 1px solid var(--color-border); }
.campaign-row:last-child { border-bottom: none; }
@media (min-width: 600px) {
  .campaign-row { grid-template-columns: 1fr auto auto auto; gap: var(--space-4); }
}

/* Mobile editor pane toggle (Edit/Preview switch) — shown only on small screens */
.pane-toggle { display: inline-flex; }

/* ============================================================================
   BREAKPOINT: large phones & up (>= 480px)
   ========================================================================== */
@media (min-width: 480px) {
  .main { padding: var(--space-6); }
  .export-row { grid-template-columns: 1fr auto auto auto; gap: var(--space-4); align-items: center; }
}

/* ============================================================================
   BREAKPOINT: tablets & up (>= 768px) — sidebar becomes persistent
   ========================================================================== */
@media (min-width: 768px) {
  .sidebar { position: sticky; transform: none; box-shadow: none; width: 240px; }
  .menu-toggle { display: none; }
  .scrim { display: none !important; }
  .main { padding: var(--space-8); }
  .empty-state { padding: var(--space-12) var(--space-6); }
  /* Editor: dual-pane (editor + preview side by side) */
  .editor-wrap { grid-template-columns: 1fr 1fr; gap: var(--space-6); }
  /* On tablet+ we have both panes visible, so the mobile toggle is hidden */
  .pane-toggle { display: none; }
  .editor-pane.is-mobile-hidden { display: flex; }
}

/* ============================================================================
   BREAKPOINT: laptops & up (>= 1024px)
   ========================================================================== */
@media (min-width: 1024px) {
  .main { max-width: 1200px; }
}

/* ============================================================================
   BREAKPOINT: wide desktops (>= 1440px)
   ========================================================================== */
@media (min-width: 1440px) {
  .main { max-width: 1320px; padding: var(--space-12); }
}

/* ============================================================================
   SMALL PHONES (< 360px) — last-ditch safety: prevent overflow
   ========================================================================== */
@media (max-width: 359px) {
  .auth-card { padding: var(--space-3); }
  .btn { padding: 0 var(--space-3); }
  .page-title { font-size: 1.25rem; }
}

/* ============================================================================
   MOBILE editor pane switching: on < md, show only the active pane (edit OR
   preview) to avoid endless scrolling; a toggle switches between them.
   ========================================================================== */
@media (max-width: 767px) {
  .editor-pane.is-mobile-hidden { display: none; }
}

/* Reduced motion preference (a11y) */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* Print: clean export-friendly */
@media print {
  .sidebar, .menu-toggle, .toast-container, .pane-toggle, .btn { display: none !important; }
  .main { padding: 0; max-width: none; }
}