/* ============================================================
 * Kakera (欠片) — clean gray + white app layout (ARCA-inspired)
 * Three-column workspace: gallery / viewport / controls.
 * Two view modes toggled in the top bar: Channels and Segmentation.
 * ============================================================ */

:root {
  /* Neutral ramp */
  --bg:          #FFFFFF;
  --bg-1:        #FAFAFA;
  --bg-2:        #F4F4F5;
  --bg-3:        #ECECEE;

  /* Ink ramp */
  --ink-900:     #18181B;
  --ink-700:     #3F3F46;
  --ink-500:     #71717A;
  --ink-400:     #A1A1AA;
  --ink-300:     #D4D4D8;

  /* Hairline */
  --line:        #E4E4E7;
  --line-strong: #D4D4D8;

  /* Accent — single, used for active state only */
  --accent:      #18181B;     /* near-black for active/selected */
  --accent-soft: #3F3F46;
  --focus-ring:  rgba(24, 24, 27, 0.18);

  /* Type */
  --font-sans: "Inter", "Helvetica Neue", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-jp:   "Noto Serif JP", "Yu Mincho", "Hiragino Mincho ProN", serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;

  /* Scale */
  --space-1:  4px;
  --space-2:  8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;

  /* Layout */
  --topbar-h:  56px;
  --bottom-h:  48px;
  --side-w:   280px;

  /* Radius / motion */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 10px;
  --ease: cubic-bezier(0.2, 0.6, 0.2, 1);
  --t-fast: 120ms;
  --t-base: 180ms;
}

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

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink-900);
  height: 100%;
}

body {
  font-family: var(--font-sans);
  font-feature-settings: "ss01", "cv11";
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}

h1, h2, h3, h4 { margin: 0; font-weight: 600; letter-spacing: -0.005em; }
p { margin: 0; }
img { display: block; max-width: 100%; height: auto; }

button {
  font: inherit;
  color: inherit;
  border: 0;
  background: transparent;
  cursor: pointer;
}

fieldset { border: 0; padding: 0; margin: 0; }
legend { padding: 0; }

a { color: var(--ink-900); text-decoration: none; }

/* Utilities */
.jp     { font-family: var(--font-jp); }
.mono   { font-family: var(--font-mono); }
.muted  { color: var(--ink-500); }
.small  { font-size: 12px; }
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}
[hidden] { display: none !important; }

.kbd {
  display: inline-block;
  padding: 2px 6px;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.85em;
  color: var(--ink-700);
}

.link-like, .link-btn {
  color: var(--ink-900);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  background: transparent;
  padding: 0;
  border: 0;
  font: inherit;
  cursor: pointer;
  transition: color var(--t-base) var(--ease);
}
.link-like:hover, .link-btn:hover { color: var(--ink-500); }

.noscript-banner {
  background: var(--ink-900);
  color: var(--bg);
  padding: var(--space-3) var(--space-5);
  text-align: center;
  font-size: 0.95rem;
}

/* ------------------------------------------------------------ */
/* Top bar                                                      */
/* ------------------------------------------------------------ */
.topbar {
  height: var(--topbar-h);
  border-bottom: 1px solid var(--line);
  background: var(--bg);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 0 var(--space-5);
  gap: var(--space-5);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.brand-mark {
  font-size: 22px;
  line-height: 1;
  color: var(--ink-900);
}
.brand-name { color: var(--ink-900); }
.brand-jp { font-weight: 500; color: var(--ink-500); margin-left: 2px; font-size: 14px; }

.mode-switch {
  display: inline-flex;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 2px;
  gap: 2px;
}
.mode-btn {
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--ink-500);
  border-radius: 4px;
  transition: background-color var(--t-base) var(--ease),
              color var(--t-base) var(--ease);
}
.mode-btn:hover { color: var(--ink-900); }
.mode-btn.is-active {
  background: var(--bg);
  color: var(--ink-900);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.topbar-right {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: var(--space-4);
}
.loaded-label {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-500);
}

/* ------------------------------------------------------------ */
/* Workspace                                                    */
/* ------------------------------------------------------------ */
.workspace {
  display: grid;
  grid-template-columns: var(--side-w) 1fr var(--side-w);
  height: calc(100vh - var(--topbar-h) - var(--bottom-h));
  overflow: hidden;
}

.sidebar {
  background: var(--bg-1);
  padding: var(--space-5);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}
.sidebar-left  { border-right: 1px solid var(--line); }
.sidebar-right { border-left:  1px solid var(--line); }

.sidebar-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-500);
  margin-bottom: var(--space-1);
}
.sidebar-subtitle {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-400);
  margin-top: var(--space-3);
}

/* ------------------------------------------------------------ */
/* Dropzone                                                     */
/* ------------------------------------------------------------ */
.dropzone {
  background: var(--bg);
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-md);
  padding: var(--space-5) var(--space-4);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  min-height: 100px;
  text-align: center;
  cursor: pointer;
  transition: border-color var(--t-base) var(--ease),
              background-color var(--t-base) var(--ease);
  outline: none;
}
.dropzone:hover,
.dropzone:focus-visible { border-color: var(--ink-700); }
.dropzone.drag-over {
  border-color: var(--ink-900);
  background: var(--bg-2);
}
.dropzone-primary { font-size: 13px; font-weight: 500; }
.dropzone-sub    { font-size: 12px; color: var(--ink-500); }
.dropzone-file   { margin-top: var(--space-2); color: var(--ink-900); word-break: break-all; }

/* ------------------------------------------------------------ */
/* Sample gallery                                               */
/* ------------------------------------------------------------ */
.sample-gallery {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-3);
}
.sample-card {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-1);
  padding: 4px;
  border: 1px solid var(--line);
  background: var(--bg);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: border-color var(--t-base) var(--ease),
              transform var(--t-fast) var(--ease);
}
.sample-card:hover {
  border-color: var(--ink-700);
}
.sample-card[aria-pressed="true"] {
  border-color: var(--ink-900);
  box-shadow: 0 0 0 1px var(--ink-900);
}
.sample-card img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: var(--radius-sm);
  background: var(--bg-2);
}
.sample-card .sample-label {
  font-size: 11px;
  color: var(--ink-700);
  text-align: center;
  line-height: 1.25;
  padding: 2px 0;
}

/* ------------------------------------------------------------ */
/* Viewport (main)                                              */
/* ------------------------------------------------------------ */
.viewport {
  background: var(--bg);
  overflow: auto;
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
}

.empty-state {
  margin: auto;
  text-align: center;
  color: var(--ink-500);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.empty-headline {
  font-size: 18px;
  font-weight: 500;
  color: var(--ink-700);
}
.empty-sub { font-size: 13px; }

/* Segmentation view */
.view-segmentation {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  width: 100%;
  max-width: 720px;
}
.seg-overlay { display: flex; justify-content: center; }
.seg-canvas-wrap {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  width: 100%;
  max-width: 560px;
  aspect-ratio: 1;
}
.seg-canvas-wrap canvas {
  width: 100%;
  height: 100%;
  border-radius: var(--radius-md);
  display: block;
}
.seg-thumbs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}
.seg-thumb {
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.seg-thumb img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: var(--radius-sm);
  background: var(--bg-2);
  border: 1px solid var(--line);
}
.seg-thumb figcaption {
  font-size: 11px;
  color: var(--ink-500);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-align: center;
}

/* Channels view (9-up) */
.view-channels { width: 100%; max-width: 820px; }
.tensor-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}
.channel-tile {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.channel-tile img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: var(--radius-sm);
  background: var(--bg-2);
  border: 1px solid var(--line);
  transition: opacity var(--t-base) var(--ease);
}
.channel-tile.is-disabled img { opacity: 0.35; }
.channel-tile .channel-name {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  font-size: 12px;
  color: var(--ink-700);
}
.channel-tile .channel-idx {
  font-family: var(--font-mono);
  color: var(--ink-400);
  font-size: 10px;
}
.channel-tile .disabled-tag {
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-900);
  font-weight: 500;
}

/* ------------------------------------------------------------ */
/* Right sidebar controls                                       */
/* ------------------------------------------------------------ */
.control-group {
  border-top: 1px solid var(--line);
  padding-top: var(--space-4);
}
.control-group:first-of-type {
  border-top: 0;
  padding-top: 0;
}
.control-group legend {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-500);
  margin-bottom: var(--space-3);
}
.control-cluster-label {
  font-size: 10px;
  color: var(--ink-400);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin: var(--space-3) 0 var(--space-2);
}
.control-cluster-label:first-child { margin-top: 0; }

.toggle-row {
  display: flex;
  gap: var(--space-3);
}
.toggle-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 13px;
  cursor: pointer;
  user-select: none;
  color: var(--ink-900);
}
.toggle input[type="checkbox"] {
  width: 14px;
  height: 14px;
  margin: 0;
  accent-color: var(--ink-900);
  cursor: pointer;
}
.toggle.inline { display: flex; }

.ablation-helper {
  display: block;
  margin-top: var(--space-3);
  padding: var(--space-2) var(--space-3);
  background: var(--bg-2);
  border-left: 2px solid var(--ink-700);
  color: var(--ink-700);
  font-size: 12px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.control-actions {
  margin-top: var(--space-3);
  display: flex;
  justify-content: flex-end;
}

.slider-row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}
.slider-row input[type="range"] {
  flex: 1;
  accent-color: var(--ink-900);
}

/* Run button */
.run-btn {
  margin-top: var(--space-2);
  width: 100%;
  padding: 10px 16px;
  background: var(--ink-900);
  color: var(--bg);
  border-radius: var(--radius-md);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: background-color var(--t-base) var(--ease),
              transform var(--t-fast) var(--ease);
}
.run-btn:hover { background: var(--accent-soft); }
.run-btn:active { transform: translateY(1px); }
.run-btn:disabled { background: var(--ink-300); cursor: not-allowed; }
.run-btn.is-loading::after {
  content: "";
  display: inline-block;
  width: 10px;
  height: 10px;
  margin-left: var(--space-2);
  border-radius: 50%;
  border: 2px solid var(--bg);
  border-right-color: transparent;
  animation: spin 600ms linear infinite;
  vertical-align: -1px;
}
@keyframes spin { to { transform: rotate(360deg); } }

.status-banner {
  margin-top: var(--space-2);
  font-size: 12px;
  color: var(--ink-900);
  background: var(--bg-2);
  border-left: 2px solid var(--ink-900);
  padding: var(--space-2) var(--space-3);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

/* ------------------------------------------------------------ */
/* Bottom strip                                                 */
/* ------------------------------------------------------------ */
.bottom-strip {
  height: var(--bottom-h);
  border-top: 1px solid var(--line);
  background: var(--bg-1);
  display: flex;
  align-items: center;
  gap: var(--space-6);
  padding: 0 var(--space-5);
}
.stat {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
}
.stat-label {
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-500);
}
.stat-value {
  font-size: 13px;
  color: var(--ink-900);
  font-weight: 500;
  font-feature-settings: "tnum";
}
.stat.right-aligned {
  margin-left: auto;
}
.stat.right-aligned .stat-label {
  text-transform: none;
  letter-spacing: 0;
  font-size: 11px;
}

/* ------------------------------------------------------------ */
/* Responsive                                                   */
/* ------------------------------------------------------------ */
@media (max-width: 1100px) {
  :root { --side-w: 240px; }
}

@media (max-width: 900px) {
  body { overflow: auto; }
  .workspace {
    grid-template-columns: 1fr;
    height: auto;
  }
  .sidebar {
    overflow: visible;
    border: 0;
    border-bottom: 1px solid var(--line);
  }
  .sidebar-right { border-bottom: 0; }
  .viewport { padding: var(--space-5); }
  .seg-thumbs { grid-template-columns: repeat(3, 1fr); }
  .tensor-grid { grid-template-columns: repeat(2, 1fr); }
  .bottom-strip {
    flex-wrap: wrap;
    height: auto;
    padding: var(--space-3) var(--space-5);
    gap: var(--space-4);
  }
}

@media (max-width: 560px) {
  .topbar {
    grid-template-columns: 1fr auto;
    gap: var(--space-3);
  }
  .mode-switch { grid-column: 1 / -1; order: 2; justify-self: stretch; }
  .topbar-right { display: none; }
  .seg-thumbs { grid-template-columns: 1fr; }
  .tensor-grid { grid-template-columns: 1fr; }
}