/* ===========================
   TOKENS
   =========================== */
:root {
  --sky-50:  #f0f9ff;
  --sky-100: #e0f2fe;
  --sky-200: #bae6fd;
  --sky-300: #7dd3fc;
  --sky-400: #38bdf8;
  --sky-500: #0ea5e9;
  --sky-600: #0284c7;
  --sky-700: #0369a1;
  --sky-800: #075985;
  --sky-900: #0c4a6e;

  --gray-50:  #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --gray-900: #0f172a;

  --font-sans: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;

  --header-h: 52px;
  --sidebar-w: 220px;
  --transition: 0.15s ease;
}

/* ===========================
   RESET
   =========================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { height: 100%; }
body {
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--gray-800);
  background: var(--sky-50);
  height: 100%;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
button { font-family: inherit; font-size: 13px; cursor: pointer; }
ul { list-style: none; }
a { text-decoration: none; color: inherit; }

/* ===========================
   HEADER
   =========================== */
.header {
  height: var(--header-h);
  background: #fff;
  border-bottom: 1px solid var(--sky-200);
  flex-shrink: 0;
  z-index: 10;
}
.header-inner {
  height: 100%;
  max-width: 100%;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 600;
  font-size: 15px;
  color: var(--sky-700);
  letter-spacing: -0.01em;
}
.logo-icon {
  width: 32px;
  height: 32px;
  background: var(--sky-600);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
}
.header-actions { display: flex; align-items: center; gap: 4px; }
.btn-ghost {
  background: none;
  border: none;
  color: var(--gray-500);
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  transition: color var(--transition), background var(--transition);
}
.btn-ghost:hover { color: var(--sky-700); background: var(--sky-50); }

/* ===========================
   LAYOUT
   =========================== */
.layout {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* ===========================
   SIDEBAR
   =========================== */
.sidebar {
  width: var(--sidebar-w);
  background: #fff;
  border-right: 1px solid var(--sky-200);
  display: flex;
  flex-direction: column;
  gap: 0;
  overflow-y: auto;
  flex-shrink: 0;
}

.section-label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--sky-500);
  padding: 16px 16px 8px;
}

/* Drop zone */
.drop-zone {
  border-bottom: 1px solid var(--sky-100);
  padding: 20px 16px;
  cursor: pointer;
  transition: background var(--transition);
}
.drop-zone:hover, .drop-zone.drag-over { background: var(--sky-50); }
.drop-zone.drag-over { border-color: var(--sky-300); }
.drop-zone-inner { display: flex; flex-direction: column; align-items: center; gap: 4px; text-align: center; }
.drop-icon { color: var(--sky-400); margin-bottom: 4px; }
.drop-title { font-weight: 500; font-size: 13px; color: var(--gray-700); }
.drop-sub { font-size: 12px; color: var(--gray-400); }
.btn-upload {
  margin-top: 10px;
  background: var(--sky-600);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 6px 16px;
  font-size: 12px;
  font-weight: 500;
  transition: background var(--transition);
}
.btn-upload:hover { background: var(--sky-700); }

/* File list */
.file-section { border-bottom: 1px solid var(--sky-100); padding-bottom: 12px; }
.file-list { display: flex; flex-direction: column; gap: 2px; padding: 0 8px; }
.file-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 8px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--transition);
  min-width: 0;
}
.file-item:hover { background: var(--sky-50); }
.file-item.selected { background: var(--sky-100); }
.file-item-icon { flex-shrink: 0; color: var(--sky-400); }
.file-item-name {
  flex: 1;
  font-size: 12px;
  color: var(--gray-700);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.file-item.selected .file-item-name { color: var(--sky-700); font-weight: 500; }
.file-item-badge {
  font-size: 10px;
  font-weight: 600;
  padding: 1px 5px;
  border-radius: 4px;
  flex-shrink: 0;
}
.badge-html { background: #fee2e2; color: #b91c1c; }
.badge-css  { background: #dbeafe; color: #1d4ed8; }
.badge-js   { background: #fef9c3; color: #b45309; }
.badge-php  { background: #ede9fe; color: #6d28d9; }
.badge-other{ background: var(--gray-100); color: var(--gray-500); }
.file-item-remove {
  background: none;
  border: none;
  padding: 2px;
  color: var(--gray-300);
  display: flex;
  border-radius: 3px;
  opacity: 0;
  transition: opacity var(--transition), color var(--transition);
}
.file-item:hover .file-item-remove { opacity: 1; }
.file-item-remove:hover { color: #ef4444; }

.btn-add-file {
  margin: 8px 16px 0;
  width: calc(100% - 32px);
  background: none;
  border: 1px dashed var(--sky-300);
  color: var(--sky-600);
  border-radius: var(--radius-sm);
  padding: 5px;
  font-size: 12px;
  transition: background var(--transition), border-color var(--transition);
}
.btn-add-file:hover { background: var(--sky-50); border-color: var(--sky-400); }

/* Download */
.download-section { padding: 0 0 16px; }
.dl-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  width: calc(100% - 32px);
  margin: 4px 16px 0;
  background: none;
  border: 1px solid var(--sky-200);
  color: var(--gray-700);
  border-radius: var(--radius-sm);
  padding: 7px 12px;
  font-size: 12px;
  font-weight: 500;
  transition: background var(--transition), border-color var(--transition), color var(--transition);
}
.dl-btn:hover { background: var(--sky-50); border-color: var(--sky-400); color: var(--sky-700); }
.dl-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.dl-note { font-size: 11px; color: var(--gray-400); margin: 8px 16px 0; }

/* ===========================
   CONTENT
   =========================== */
.content {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  overflow: hidden;
}

/* Empty state */
.empty-state {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--gray-400);
  padding: 40px;
}
.empty-icon { color: var(--sky-200); margin-bottom: 8px; }
.empty-title { font-size: 15px; font-weight: 500; color: var(--gray-500); }
.empty-sub { font-size: 13px; color: var(--gray-400); text-align: center; max-width: 280px; }

/* Workspace */
.workspace {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* Toolbar */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: #fff;
  border-bottom: 1px solid var(--sky-200);
  flex-shrink: 0;
}
.tab-group { display: flex; gap: 2px; background: var(--sky-50); border-radius: var(--radius-sm); padding: 2px; }
.tab {
  background: none;
  border: none;
  padding: 4px 14px;
  border-radius: calc(var(--radius-sm) - 1px);
  color: var(--gray-500);
  font-size: 13px;
  font-weight: 500;
  transition: background var(--transition), color var(--transition);
}
.tab.active { background: #fff; color: var(--sky-700); box-shadow: 0 1px 3px rgba(0,0,0,0.08); }
.tab:not(.active):hover { color: var(--gray-700); }

.size-group { display: flex; gap: 2px; background: var(--sky-50); border-radius: var(--radius-sm); padding: 2px; }
.size-btn {
  background: none;
  border: none;
  padding: 5px 8px;
  border-radius: calc(var(--radius-sm) - 1px);
  color: var(--gray-400);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), color var(--transition);
}
.size-btn.active { background: #fff; color: var(--sky-600); box-shadow: 0 1px 3px rgba(0,0,0,0.08); }
.size-btn:not(.active):hover { color: var(--gray-600); }

/* Tab panels */
.tab-panel { flex: 1; overflow: hidden; display: flex; flex-direction: column; }

/* Frame wrapper */
.frame-wrapper {
  flex: 1;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  background: var(--sky-100);
  overflow: auto;
  padding: 16px;
}
#previewFrame {
  background: #fff;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 24px rgba(14, 165, 233, 0.12);
  width: 100%;
  height: 100%;
  min-height: 400px;
  transition: width var(--transition), height var(--transition);
}

/* Code panel */
.code-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--gray-900);
  flex-shrink: 0;
}
.code-badge {
  font-size: 11px;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--sky-600);
  color: #fff;
  letter-spacing: 0.04em;
}
.code-filename { font-size: 12px; color: var(--gray-400); font-family: var(--font-mono); }
.btn-copy {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 5px;
  background: none;
  border: 1px solid var(--gray-600);
  color: var(--gray-400);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  font-size: 12px;
  transition: border-color var(--transition), color var(--transition);
}
.btn-copy:hover { border-color: var(--sky-500); color: var(--sky-400); }
.btn-copy.copied { border-color: #22c55e; color: #22c55e; }

.code-block {
  flex: 1;
  overflow: auto;
  background: var(--gray-900);
  color: #e2e8f0;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  padding: 20px 24px;
  white-space: pre;
  tab-size: 2;
}

/* ===========================
   TOAST
   =========================== */
.toast {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: var(--gray-800);
  color: #fff;
  font-size: 13px;
  padding: 9px 16px;
  border-radius: var(--radius-md);
  display: none;
  align-items: center;
  gap: 7px;
  z-index: 100;
  box-shadow: 0 4px 16px rgba(0,0,0,0.2);
  animation: slideUp 0.2s ease;
}
.toast.show { display: flex; }
.toast-dot { width: 7px; height: 7px; border-radius: 50%; background: #22c55e; flex-shrink: 0; }

@keyframes slideUp {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ===========================
   RESPONSIVE
   =========================== */
@media (max-width: 640px) {
  :root { --sidebar-w: 180px; }
  .size-group { display: none; }
}