:root {
  --bg: #f6f7fb;
  --bg-grad-start: #f8fafc;
  --bg-grad-end: #eef2f9;
  --panel: #ffffff;
  --text: #1f2430;
  --muted: #626b7a;
  --border: #d8dce5;
  --accent: #1f6feb;
  --accent-soft: #e8f1ff;
  --danger: #cc3344;
  --panel-shadow: 0 6px 16px rgba(18, 33, 67, 0.06);
  --textarea-bg: #fcfdff;
  --drop-bg: #f2f7ff;
  --drop-bg-dragging: #e8f1ff;
  --drop-bg-page-dragging: #e6f0ff;
  --drop-text: #4f5f80;
  --code-bg: #f1f3f8;
  --preview-bg: #f7faff;
  --saved-item-bg: #fcfdff;
  --edge-toggle-bg: #ffffff;
  --edge-toggle-border: #cbd9f3;
  --edge-toggle-shadow: 0 6px 16px rgba(18, 33, 67, 0.15);
}

html[data-theme="light"] {
  color-scheme: light;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0f1522;
  --bg-grad-start: #141d2f;
  --bg-grad-end: #0d1423;
  --panel: #111b2d;
  --text: #e8edf8;
  --muted: #9ba8c4;
  --border: #2b3b58;
  --accent: #63a3ff;
  --accent-soft: #16315d;
  --danger: #ff7f90;
  --panel-shadow: 0 10px 24px rgba(0, 0, 0, 0.35);
  --textarea-bg: #0d1729;
  --drop-bg: #172640;
  --drop-bg-dragging: #1b3460;
  --drop-bg-page-dragging: #1f3f73;
  --drop-text: #c4d7ff;
  --code-bg: #1a2942;
  --preview-bg: #122038;
  --saved-item-bg: #14233d;
  --edge-toggle-bg: #1a2c49;
  --edge-toggle-border: #3f5b88;
  --edge-toggle-shadow: 0 10px 24px rgba(0, 0, 0, 0.4);
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #0f1522;
    --bg-grad-start: #141d2f;
    --bg-grad-end: #0d1423;
    --panel: #111b2d;
    --text: #e8edf8;
    --muted: #9ba8c4;
    --border: #2b3b58;
    --accent: #63a3ff;
    --accent-soft: #16315d;
    --danger: #ff7f90;
    --panel-shadow: 0 10px 24px rgba(0, 0, 0, 0.35);
    --textarea-bg: #0d1729;
    --drop-bg: #172640;
    --drop-bg-dragging: #1b3460;
    --drop-bg-page-dragging: #1f3f73;
    --drop-text: #c4d7ff;
    --code-bg: #1a2942;
    --preview-bg: #122038;
    --saved-item-bg: #14233d;
    --edge-toggle-bg: #1a2c49;
    --edge-toggle-border: #3f5b88;
    --edge-toggle-shadow: 0 10px 24px rgba(0, 0, 0, 0.4);
  }

  html[data-theme="light"] {
    color-scheme: light;
    --bg: #f6f7fb;
    --bg-grad-start: #f8fafc;
    --bg-grad-end: #eef2f9;
    --panel: #ffffff;
    --text: #1f2430;
    --muted: #626b7a;
    --border: #d8dce5;
    --accent: #1f6feb;
    --accent-soft: #e8f1ff;
    --danger: #cc3344;
    --panel-shadow: 0 6px 16px rgba(18, 33, 67, 0.06);
    --textarea-bg: #fcfdff;
    --drop-bg: #f2f7ff;
    --drop-bg-dragging: #e8f1ff;
    --drop-bg-page-dragging: #e6f0ff;
    --drop-text: #4f5f80;
    --code-bg: #f1f3f8;
    --preview-bg: #f7faff;
    --saved-item-bg: #fcfdff;
    --edge-toggle-bg: #ffffff;
    --edge-toggle-border: #cbd9f3;
    --edge-toggle-shadow: 0 6px 16px rgba(18, 33, 67, 0.15);
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background: linear-gradient(120deg, var(--bg-grad-start) 0%, var(--bg-grad-end) 100%);
}

.app {
  width: calc(100% - 2rem);
  margin: 1.5rem auto;
  display: grid;
  grid-template-columns: minmax(320px, 1.1fr) minmax(0, 2fr) minmax(240px, 0.8fr);
  gap: 1rem;
}

.app.left-collapsed {
  grid-template-columns: minmax(0, 1fr) minmax(240px, 0.8fr);
}

.app.right-collapsed {
  grid-template-columns: minmax(320px, 1.1fr) minmax(0, 1fr);
}

.app.left-collapsed.right-collapsed {
  grid-template-columns: minmax(0, 1fr);
}

.app.left-collapsed.right-collapsed .preview-header {
  display: none;
}

.app.left-collapsed .input-panel {
  display: none;
}

.app.right-collapsed .saved-panel {
  display: none;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
  box-shadow: var(--panel-shadow);
  min-height: 200px;
}

h1,
h2 {
  margin: 0 0 0.5rem;
}

h1 {
  font-size: 1.25rem;
}

h2 {
  font-size: 1.05rem;
}

.preview-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.8rem;
  margin-bottom: 0.5rem;
}

.preview-header h2 {
  margin: 0;
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 0.7rem;
}

.panel-controls {
  display: flex;
  gap: 0.45rem;
}

.panel-controls button {
  padding: 0.35rem 0.6rem;
  font-size: 0.85rem;
}

.theme-controls {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--muted);
  font-size: 0.85rem;
}

.theme-label {
  font-weight: 600;
}

.theme-controls select {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.35rem 0.5rem;
  background: var(--panel);
  color: var(--text);
}

.subtle {
  color: var(--muted);
  margin: 0 0 0.75rem;
  font-size: 0.9rem;
}

.label {
  font-size: 0.9rem;
  font-weight: 600;
}

textarea {
  width: 100%;
  min-height: 250px;
  resize: vertical;
  margin-top: 0.4rem;
  padding: 0.75rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  font: 0.95rem/1.4 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  color: var(--text);
  background: var(--textarea-bg);
}

.drop-zone {
  margin-top: 0.75rem;
  border: 2px dashed var(--border);
  border-radius: 10px;
  padding: 1.1rem;
  text-align: center;
  color: var(--drop-text);
  background: var(--drop-bg);
  cursor: pointer;
  transition: transform 140ms ease, border-color 140ms ease, background 140ms ease, color 140ms ease,
    box-shadow 140ms ease;
}

.drop-zone.is-dragging {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--drop-bg-dragging);
  transform: scale(1.03);
  box-shadow: 0 10px 24px rgba(31, 111, 235, 0.15);
}

body.file-dragging .drop-zone {
  border-color: #6ca4ff;
  background: var(--drop-bg-page-dragging);
  transform: scale(1.06);
  box-shadow: 0 14px 30px rgba(34, 90, 180, 0.2);
}

.actions {
  margin-top: 0.75rem;
  display: flex;
  gap: 0.6rem;
}

button {
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  border-radius: 8px;
  padding: 0.5rem 0.85rem;
  cursor: pointer;
}

button.secondary {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.preview {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.9rem;
  min-height: 550px;
  overflow: auto;
  background: var(--preview-bg);
}

.preview :first-child {
  margin-top: 0;
}

.preview code {
  background: var(--code-bg);
  padding: 0.1rem 0.3rem;
  border-radius: 5px;
}

.saved-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.55rem;
}

.saved-item {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.5rem;
  background: var(--saved-item-bg);
}

.saved-item button {
  width: 100%;
  border-color: var(--border);
  background: transparent;
  color: var(--text);
  text-align: left;
  display: block;
}

.saved-meta {
  margin-top: 0.35rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
  color: var(--muted);
  font-size: 0.8rem;
}

.saved-meta .delete {
  border: 1px solid transparent;
  padding: 0;
  background: transparent;
  color: var(--danger);
}

.empty {
  color: var(--muted);
  font-size: 0.9rem;
}

.edge-toggle {
  position: fixed;
  top: 0.95rem;
  z-index: 20;
  border-color: var(--edge-toggle-border);
  background: var(--edge-toggle-bg);
  color: var(--text);
  box-shadow: var(--edge-toggle-shadow);
}

.edge-toggle:hover {
  filter: brightness(1.03);
}

.edge-toggle.left {
  left: 1rem;
}

.edge-toggle.right {
  right: 1rem;
}

@media (max-width: 980px) {
  .app {
    grid-template-columns: 1fr;
  }

  .app.left-collapsed,
  .app.right-collapsed,
  .app.left-collapsed.right-collapsed {
    grid-template-columns: 1fr;
  }

  .panel-controls {
    display: none;
  }

  .preview {
    min-height: 260px;
  }
}