/* ── Chirpy-derived design tokens ── */
:root {
  /* dark theme (default) */
  --font-mono: ui-monospace, monospace;
  --main-bg: rgb(27 27 30);
  --main-border-color: rgb(44 45 45);
  --text-color: rgb(175 176 177);
  --text-muted-color: #868686;
  --heading-color: #cccccc;
  --label-color: #a7a7a7;
  --link-color: rgb(138 180 248);
  --sidebar-bg: #1e1e1e;
  --sidebar-border-color: #292929;
  --card-bg: #1e1e1e;
  --card-hover-bg: #464d51;
  --btn-border-color: #2e2f31;
  --button-bg: #1e1e1e;
  --accent-color: #7b7bf0;
  --accent-hover: #8e8ef8;
  --accent-bg: #2a2a4a;
  --accent-text: #a0a0ff;
  --saving-color: #5cbf8a;
  --larger-color: #cf7b5c;
  --error-color: #cf7b5c;
  --handle-line: rgba(255 255 255 / 80%);
}

@media (prefers-color-scheme: light) {
  :root {
    --main-bg: white;
    --main-border-color: #f3f3f3;
    --text-color: #34343c;
    --text-muted-color: #757575;
    --heading-color: #2a2a2a;
    --label-color: #585858;
    --link-color: #0056b2;
    --sidebar-bg: #f6f8fa;
    --sidebar-border-color: #efefef;
    --card-bg: white;
    --card-hover-bg: #e2e2e2;
    --btn-border-color: #e9ecef;
    --button-bg: #ffffff;
    --accent-color: #0056b2;
    --accent-hover: #0066cc;
    --accent-bg: #e8f0fb;
    --accent-text: #0056b2;
    --saving-color: #1a7a40;
    --larger-color: #b34a2a;
    --error-color: #b34a2a;
    --handle-line: rgba(0 0 0 / 50%);
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  font-family:
    "Source Sans 3", "Source Sans Pro", "Microsoft Yahei", sans-serif;
  background: var(--main-bg);
  color: var(--text-color);
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

.container {
  width: 100%;
  max-width: 1600px;
  align-self: center;
  display: grid;
  grid-template-columns: 260px 1fr;
  grid-template-rows: auto 1fr;
  gap: 1rem 1.5rem;
  flex: 1;
  padding: 1rem;
}

/* ── Header ── */
.app-header {
  grid-column: 1 / -1;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

h1 {
  font-family: "Lato", "Microsoft Yahei", sans-serif;
  font-size: 1.2rem;
  font-weight: 600;
  margin: 0;
  color: var(--heading-color);
  letter-spacing: -0.02em;
  white-space: nowrap;
}

.status-bar {
  font-size: 0.82rem;
  color: var(--text-muted-color);
  text-align: right;
  min-height: 1.2em;
}

.status-bar.loading {
  color: var(--label-color);
}
.status-bar.error {
  color: var(--error-color);
}

/* ── Sidebar ── */
.sidebar {
  grid-column: 1;
  grid-row: 2;
  overflow-y: auto;
  overflow-x: hidden;
  max-height: calc(100vh - 3.5rem);
  position: sticky;
  top: 1rem;
  scrollbar-width: thin;
  scrollbar-color: var(--btn-border-color) transparent;
  padding-right: 0.25rem;
}

.divider {
  border: none;
  border-top: 1px solid var(--main-border-color);
  margin: 1rem 0;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

label {
  font-size: 0.94rem;
  color: var(--label-color);
}

.quality-row {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.quality-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent-color);
  cursor: pointer;
}

.section-label {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted-color);
  margin-bottom: 0.4rem;
}

.format-select {
  display: flex;
  gap: 0.25rem;
  flex-wrap: nowrap;
}

.format-btn {
  padding: 0.18rem 0.4rem;
  border-radius: 6px;
  border: 1px solid var(--btn-border-color);
  background: var(--button-bg);
  color: var(--label-color);
  font-size: 0.78rem;
  cursor: pointer;
  transition: all 0.1s;
  font-family: inherit;
  white-space: nowrap;
}

.format-btn:hover {
  border-color: var(--text-muted-color);
  color: var(--text-color);
}

.format-btn.active {
  background: var(--accent-bg);
  border-color: var(--accent-color);
  color: var(--accent-text);
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  accent-color: var(--accent-color);
  cursor: pointer;
  flex-shrink: 0;
}

.toggle-group {
  display: flex;
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--btn-border-color);
  width: fit-content;
}

.toggle-btn {
  padding: 0.25rem 0.6rem;
  border: none;
  border-right: 1px solid var(--btn-border-color);
  background: var(--button-bg);
  color: var(--text-muted-color);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.1s;
  font-family: inherit;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.toggle-btn:last-child {
  border-right: none;
}
.toggle-btn:hover {
  background: var(--sidebar-bg);
  color: var(--text-color);
}
.toggle-btn.active {
  background: var(--accent-bg);
  color: var(--accent-text);
}

.option-with-controls {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.option-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.sub-controls {
  padding-left: 1.6rem;
}
.sub-controls.hidden {
  display: none;
}

.hint {
  font-size: 0.8rem;
  color: var(--text-muted-color);
  margin-top: 0.2rem;
}

.hint-tag {
  font-size: 0.78rem;
  color: var(--text-muted-color);
  margin-left: 0.4rem;
}

.process-btn {
  width: 100%;
  padding: 0.65rem;
  border-radius: 8px;
  border: none;
  background: var(--accent-color);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  font-family: inherit;
  transition:
    background 0.15s,
    opacity 0.15s;
  margin-top: 0.25rem;
}

.process-btn:hover:not(:disabled) {
  background: var(--accent-hover);
}
.process-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* ── Workspace ── */
.workspace {
  grid-column: 2;
  grid-row: 2;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-width: 0;
}

/* ── Comparison area ── */
.comparison-wrapper {
  background: var(--sidebar-bg);
  border-radius: 12px;
  border: 1px solid var(--main-border-color);
  overflow: hidden;
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 320px;
}

.comparison-empty {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  color: var(--text-muted-color);
  font-size: 0.9rem;
  user-select: none;
  cursor: pointer;
  transition: background 0.15s;
}

.comparison-empty:hover {
  background: var(--card-hover-bg);
}

.comparison-wrapper.drag-over .comparison-empty {
  background: var(--card-hover-bg);
  color: var(--label-color);
}

.comparison-wrapper.drag-over {
  border-color: var(--text-muted-color);
}

.comparison-empty input[type="file"] {
  display: none;
}

.comparison-empty-icon {
  font-size: 2rem;
  line-height: 1;
  opacity: 0.3;
}

.comparison-empty-sub {
  font-size: 0.75rem;
  color: var(--text-muted-color);
  opacity: 0.7;
}

/* The slider container — both panes are position:absolute inside */
.comparison-slider {
  position: relative;
  flex: 1;
  overflow: hidden;
  cursor: col-resize;
  --split: 50%;
  display: none; /* shown once first result loads */
  min-height: 280px;
}

.comparison-pane {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

.comparison-pane--original {
  clip-path: inset(0 calc(100% - var(--split)) 0 0);
}

.comparison-pane--processed {
  clip-path: inset(0 0 0 var(--split));
}

.comparison-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  pointer-events: none;
  user-select: none;
  -webkit-user-drag: none;
}

.pane-label {
  position: absolute;
  bottom: 0.6rem;
  background: rgba(0, 0, 0, 0.55);
  color: #e8e8e8;
  font-size: 0.72rem;
  padding: 0.18rem 0.5rem;
  border-radius: 4px;
  pointer-events: none;
  user-select: none;
}

.comparison-pane--original .pane-label {
  left: 0.6rem;
}
.comparison-pane--processed .pane-label {
  right: 0.6rem;
}

/* Drag handle */
.slider-handle {
  position: absolute;
  top: 0;
  bottom: 0;
  left: var(--split);
  transform: translateX(-50%);
  width: 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  cursor: col-resize;
  z-index: 10;
  pointer-events: none; /* clicks pass through to the slider container */
}

.handle-line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 2px;
  background: var(--handle-line);
  pointer-events: none;
}

.handle-knob {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
  z-index: 1;
  flex-shrink: 0;
}

.handle-icon {
  font-size: 0.85rem;
  color: #333;
  letter-spacing: -1px;
  user-select: none;
}

/* Metadata bar */
.comparison-meta {
  padding: 0.5rem 0.85rem;
  background: var(--card-bg);
  border-top: 1px solid var(--main-border-color);
  display: none; /* shown once first result loads */
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  color: var(--text-muted-color);
  flex-shrink: 0;
  gap: 1rem;
}

.meta-filename {
  color: var(--label-color);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}

.meta-size {
  white-space: nowrap;
  flex-shrink: 0;
}
.meta-size .saving {
  color: var(--saving-color);
}
.meta-size .larger {
  color: var(--larger-color);
}

/* ── Filmstrip ── */
.results-filmstrip {
  display: flex;
  flex-direction: row;
  gap: 0.5rem;
  overflow-x: auto;
  overflow-y: hidden;
  flex-wrap: nowrap;
  padding: 0.25rem 0 0.5rem;
  scrollbar-width: thin;
  scrollbar-color: var(--btn-border-color) transparent;
  min-height: 88px;
  flex-shrink: 0;
}

.result-item {
  background: var(--card-bg);
  border: 1px solid var(--btn-border-color);
  border-radius: 8px;
  padding: 0.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.3rem;
  cursor: pointer;
  flex-shrink: 0;
  width: 88px;
  transition:
    border-color 0.1s,
    background 0.1s;
  position: relative;
}

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

.result-item.selected {
  border-color: var(--accent-color);
  background: var(--accent-bg);
}

.result-item.error-item {
  cursor: default;
  opacity: 0.6;
}

.result-thumb {
  width: 52px;
  height: 52px;
  border-radius: 4px;
  object-fit: cover;
  border: 1px solid var(--main-border-color);
  flex-shrink: 0;
}

.result-name {
  font-size: 0.68rem;
  color: var(--label-color);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 76px;
  text-align: center;
}

.result-saving {
  font-size: 0.68rem;
  color: var(--text-muted-color);
  text-align: center;
}

.result-saving .saving {
  color: var(--saving-color);
}
.result-saving .larger {
  color: var(--larger-color);
}

.result-download {
  position: absolute;
  top: 3px;
  right: 3px;
  width: 18px;
  height: 18px;
  border-radius: 3px;
  border: 1px solid var(--btn-border-color);
  background: var(--button-bg);
  color: var(--text-muted-color);
  font-size: 0.65rem;
  cursor: pointer;
  text-decoration: none;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.1s;
  line-height: 1;
}

.result-item:hover .result-download {
  opacity: 1;
}
.result-download:hover {
  color: var(--accent-text);
  border-color: var(--accent-color);
}

/* ── Footer ── */
footer {
  background: var(--sidebar-bg);
  border-top: 1px solid var(--main-border-color);
  padding: 15px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.88rem;
  color: var(--text-muted-color);
}

footer a {
  color: var(--link-color);
  text-decoration: none;
}
footer a:hover {
  text-decoration: underline;
}

/* ── Responsive ── */
@media (max-width: 860px) {
  .container {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto;
  }

  .app-header {
    grid-column: 1;
  }

  .sidebar {
    max-height: none;
    position: static;
    overflow: visible;
  }

  .workspace {
    grid-column: 1;
  }
}