/* ============================================================
   FlexGrid Lab — styles
   Dark developer-tool aesthetic. Accent color switches per mode.
   ============================================================ */

:root {
  --bg: #0a0d13;
  --bg-soft: #0e1219;
  --panel: #12161f;
  --panel-2: #171c27;
  --panel-3: #1d2331;
  --border: #242c3d;
  --border-soft: #1c2330;
  --text: #e8ecf4;
  --text-dim: #aab3c5;
  --muted: #7c8698;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, "Helvetica Neue", Arial, sans-serif;
  --radius: 10px;
  --radius-sm: 7px;
  --shadow: 0 10px 30px rgba(0, 0, 0, .35);
}

body[data-mode="flex"] {
  --accent: #38bdf8;
  --accent-strong: #0ea5e9;
  --accent-soft: rgba(56, 189, 248, .13);
  --accent-line: rgba(56, 189, 248, .45);
}

body[data-mode="grid"] {
  --accent: #a78bfa;
  --accent-strong: #8b5cf6;
  --accent-soft: rgba(167, 139, 250, .13);
  --accent-line: rgba(167, 139, 250, .45);
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  background:
    radial-gradient(1100px 500px at 85% -10%, var(--accent-soft), transparent 60%),
    radial-gradient(900px 500px at -10% 110%, rgba(56, 189, 248, .05), transparent 55%),
    var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 1.45;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

::selection { background: var(--accent-line); color: #fff; }

/* ---------- scrollbars ---------- */
* { scrollbar-width: thin; scrollbar-color: #2c3547 transparent; }
*::-webkit-scrollbar { width: 9px; height: 9px; }
*::-webkit-scrollbar-thumb { background: #2c3547; border-radius: 8px; border: 2px solid var(--panel); }
*::-webkit-scrollbar-track { background: transparent; }

/* ============================================================
   Header
   ============================================================ */

.app-header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 18px;
  border-bottom: 1px solid var(--border-soft);
  background: rgba(14, 18, 25, .8);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 40;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 650;
  font-size: 15px;
  letter-spacing: .01em;
  white-space: nowrap;
}

.brand-mark {
  width: 26px; height: 26px;
  border-radius: 7px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr 1fr;
  gap: 2px;
  padding: 3px;
  background: var(--panel-3);
  border: 1px solid var(--border);
}
.brand-mark i { border-radius: 2px; background: var(--accent); transition: background .3s; }
.brand-mark i:nth-child(2) { background: #46536e; }
.brand-mark i:nth-child(3) { background: #46536e; }

.brand small {
  color: var(--muted);
  font-weight: 450;
  font-size: 12px;
  margin-left: 2px;
}

.mode-tabs {
  display: flex;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
  gap: 2px;
}

.mode-tab {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--text-dim);
  font: inherit;
  font-weight: 600;
  font-size: 13px;
  padding: 6px 18px;
  border-radius: 999px;
  cursor: pointer;
  transition: color .18s, background .18s, box-shadow .18s;
}

.mode-tab:hover { color: var(--text); }

.mode-tab[aria-pressed="true"] {
  background: var(--accent);
  color: #08111c;
  box-shadow: 0 2px 10px var(--accent-line);
}

.header-spacer { flex: 1; }

.header-actions { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }

/* ============================================================
   Buttons, inputs, shared control chrome
   ============================================================ */

.btn {
  appearance: none;
  font: inherit;
  font-size: 13px;
  font-weight: 550;
  color: var(--text-dim);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background .15s, color .15s, border-color .15s, transform .05s;
  white-space: nowrap;
}

.btn:hover { color: var(--text); border-color: #33405a; background: var(--panel-3); }
.btn:active { transform: translateY(1px); }

.btn-accent {
  background: var(--accent);
  border-color: transparent;
  color: #08111c;
}
.btn-accent:hover { background: var(--accent-strong); color: #04101c; border-color: transparent; }

.btn-ghost { background: transparent; }
.btn-ghost:hover { background: var(--panel-2); }

.btn-sm { padding: 4px 9px; font-size: 12px; border-radius: 6px; }

.btn-icon { padding: 5px 8px; line-height: 1; }

.btn:disabled { opacity: .45; cursor: not-allowed; }
.btn:disabled:hover { background: var(--panel-2); color: var(--text-dim); border-color: var(--border); }

select.btn {
  padding-right: 26px;
  background-image: linear-gradient(45deg, transparent 50%, var(--muted) 50%), linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position: calc(100% - 14px) 55%, calc(100% - 9px) 55%;
  background-size: 5px 5px;
  background-repeat: no-repeat;
}

/* focus visibility everywhere */
:focus { outline: none; }
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ============================================================
   Main 3-pane layout
   ============================================================ */

.app-main {
  flex: 1;
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr) 360px;
  gap: 0;
  min-height: 0;
}

.controls-panel {
  border-right: 1px solid var(--border-soft);
  background: var(--bg-soft);
  overflow-y: auto;
  padding: 14px 14px 40px;
}

.code-panel {
  border-left: 1px solid var(--border-soft);
  background: var(--bg-soft);
  overflow-y: auto;
  padding: 14px 14px 40px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.canvas-panel {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
}

@media (max-width: 1240px) {
  .app-main { grid-template-columns: 280px minmax(0, 1fr); grid-template-rows: minmax(380px, 55vh) auto; }
  .canvas-panel { grid-column: 2; grid-row: 1; }
  .controls-panel { grid-column: 1; grid-row: 1 / span 2; }
  .code-panel { grid-column: 2; grid-row: 2; border-left: 0; border-top: 1px solid var(--border-soft); }
}

@media (max-width: 820px) {
  .app-main { display: flex; flex-direction: column; }
  .canvas-panel { order: -1; min-height: 420px; border-bottom: 1px solid var(--border-soft); }
  .controls-panel { border-right: 0; overflow: visible; }
  .code-panel { border-left: 0; overflow: visible; }
  .brand small { display: none; }
}

/* ============================================================
   Controls panel
   ============================================================ */

.control-section { margin-bottom: 20px; }

.control-section > h3 {
  margin: 0 0 10px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .09em;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 8px;
}

.control-section > h3::after { content: ""; flex: 1; height: 1px; background: var(--border-soft); }

.control-section h3 .tag {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .04em;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid var(--accent-line);
  padding: 1px 7px;
  border-radius: 99px;
  text-transform: none;
}

.control-group { margin-bottom: 12px; }

.control-label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--text-dim);
  margin-bottom: 6px;
}

.control-label .value {
  color: var(--accent);
  font-weight: 600;
  max-width: 62%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  text-align: right;
}

/* segmented control */
.seg {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  background: var(--panel);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  padding: 4px;
}

.seg-btn {
  appearance: none;
  font: inherit;
  flex: 1 1 auto;
  min-width: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  padding: 6px 4px;
  border: 1px solid transparent;
  border-radius: 6px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  transition: background .15s, color .15s, border-color .15s;
}

.seg-btn svg { display: block; }

.seg-btn .seg-caption { font-size: 9.5px; font-weight: 600; letter-spacing: .02em; line-height: 1; }

.seg-btn:hover { color: var(--text-dim); background: var(--panel-2); }

.seg-btn[aria-pressed="true"] {
  background: var(--accent-soft);
  border-color: var(--accent-line);
  color: var(--accent);
}

/* slider + number combo */
.slider-row { display: flex; align-items: center; gap: 10px; }

input[type="range"] {
  flex: 1;
  appearance: none;
  -webkit-appearance: none;
  height: 4px;
  border-radius: 4px;
  background: linear-gradient(to right, var(--accent) var(--fill, 50%), #2a3346 var(--fill, 50%));
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 15px; height: 15px;
  border-radius: 50%;
  background: var(--text);
  border: 3px solid var(--accent);
  box-shadow: 0 1px 6px rgba(0,0,0,.5);
  transition: transform .12s;
}
input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.15); }
input[type="range"]::-moz-range-thumb {
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--text); border: 3px solid var(--accent);
}

.num-input {
  width: 58px;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 5px 6px;
  text-align: right;
}
.num-input:hover { border-color: #33405a; }
.num-input:focus-visible { outline-offset: 0; border-color: var(--accent); }

/* stepper */
.stepper { display: inline-flex; align-items: stretch; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; background: var(--panel); }
.stepper button {
  appearance: none; border: 0; background: var(--panel-2); color: var(--text-dim);
  font: inherit; font-weight: 700; width: 26px; cursor: pointer;
}
.stepper button:hover { background: var(--panel-3); color: var(--text); }
.stepper input {
  width: 52px; border: 0; background: transparent; color: var(--text);
  font-family: var(--mono); font-size: 12px; text-align: center; padding: 5px 2px;
}
.stepper input:focus-visible { outline-offset: -2px; }

.field-row { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 10px; }
.field-row > .control-label { margin-bottom: 0; }

/* track editor */
.track-list { display: flex; flex-direction: column; gap: 6px; }

.track-row {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--panel);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  padding: 4px 6px;
}

.track-idx {
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--muted);
  width: 18px;
  text-align: center;
  flex: none;
}

.track-row .num-input { flex: 1; width: auto; min-width: 0; }

.track-unit {
  appearance: none;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--text-dim);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 5px;
  cursor: pointer;
}
.track-unit:hover { color: var(--text); border-color: #33405a; }

.track-del {
  appearance: none; border: 0; background: transparent; color: var(--muted);
  font: inherit; font-size: 14px; line-height: 1; cursor: pointer;
  width: 22px; height: 22px; border-radius: 5px; flex: none;
}
.track-del:hover { color: #f87171; background: rgba(248, 113, 113, .12); }

.track-add {
  width: 100%;
  justify-content: center;
  border-style: dashed;
  color: var(--muted);
  margin-top: 6px;
}
.track-add:hover { color: var(--accent); border-color: var(--accent-line); }

.mini-note { font-size: 11px; color: var(--muted); margin-top: 6px; line-height: 1.5; }
.mini-note code { font-family: var(--mono); font-size: 10.5px; color: var(--text-dim); background: var(--panel-2); padding: 1px 5px; border-radius: 4px; }

/* item chip list */
.item-chips { display: flex; flex-wrap: wrap; gap: 6px; }

.item-chip {
  appearance: none;
  font: inherit;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--text-dim);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 5px 9px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: border-color .15s, color .15s, background .15s;
}
.item-chip .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--chip-hue, var(--accent)); }
.item-chip:hover { border-color: #33405a; color: var(--text); }
.item-chip[aria-pressed="true"] { border-color: var(--accent-line); background: var(--accent-soft); color: var(--accent); }

.empty-hint {
  border: 1px dashed var(--border);
  border-radius: var(--radius-sm);
  color: var(--muted);
  font-size: 12px;
  padding: 14px;
  text-align: center;
  line-height: 1.6;
}

/* ============================================================
   Canvas
   ============================================================ */

.canvas-toolbar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 14px;
  border-bottom: 1px solid var(--border-soft);
  background: rgba(14, 18, 25, .6);
  flex-wrap: wrap;
}

.canvas-toolbar .tb-group { display: flex; align-items: center; gap: 6px; }
.canvas-toolbar .tb-label { font-size: 11px; color: var(--muted); font-weight: 600; text-transform: uppercase; letter-spacing: .07em; margin-right: 2px; }
.canvas-toolbar .tb-sep { width: 1px; height: 20px; background: var(--border-soft); }
.canvas-toolbar .spacer { flex: 1; }

.size-pill {
  appearance: none; font: inherit; font-family: var(--mono); font-size: 11px;
  color: var(--muted); background: transparent; border: 1px solid var(--border);
  border-radius: 99px; padding: 3px 10px; cursor: pointer;
  transition: color .15s, border-color .15s, background .15s;
}
.size-pill:hover { color: var(--text); border-color: #33405a; }
.size-pill[aria-pressed="true"] { color: var(--accent); border-color: var(--accent-line); background: var(--accent-soft); }

.toggle-pill {
  appearance: none; font: inherit; font-size: 11px; font-weight: 600;
  color: var(--muted); background: transparent; border: 1px solid var(--border);
  border-radius: 99px; padding: 3px 10px; cursor: pointer; display: inline-flex; align-items: center; gap: 5px;
}
.toggle-pill:hover { color: var(--text); }
.toggle-pill[aria-pressed="true"] { color: var(--accent); border-color: var(--accent-line); background: var(--accent-soft); }

.canvas-scroll {
  flex: 1;
  overflow: auto;
  padding: 26px;
  background-image: radial-gradient(circle, #1b2231 1px, transparent 1px);
  background-size: 22px 22px;
}

.stage {
  min-height: 100%;
  display: flex;
  align-items: flex-start;
  justify-content: center;
}

.stage-frame {
  position: relative;
  max-width: 100%;
}

.demo-container {
  position: relative;
  background: rgba(23, 28, 39, .55);
  border: 1.5px dashed #35415c;
  border-radius: var(--radius);
  padding: 10px;
  transition: border-color .2s;
  min-width: 120px;
  min-height: 90px;
  backdrop-filter: blur(2px);
}

.stage-frame:hover .demo-container { border-color: #43527a; }

.demo-container.grid-outline {
  background-image:
    linear-gradient(var(--accent-soft) 0 0);
  background-repeat: no-repeat;
}

.container-badge {
  position: absolute;
  top: -11px;
  left: 12px;
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--accent);
  background: var(--bg);
  border: 1px solid var(--accent-line);
  padding: 1px 8px;
  border-radius: 99px;
  pointer-events: none;
  white-space: nowrap;
  z-index: 3;
}

/* resize handles */
.rz-handle {
  position: absolute;
  z-index: 5;
  touch-action: none;
}
.rz-handle-x {
  top: 50%; right: -17px;
  width: 12px; height: 44px;
  transform: translateY(-50%);
  cursor: ew-resize;
}
.rz-handle-y {
  left: 50%; bottom: -17px;
  width: 44px; height: 12px;
  transform: translateX(-50%);
  cursor: ns-resize;
}
.rz-handle::before {
  content: "";
  position: absolute; inset: 0;
  border-radius: 99px;
  background: var(--panel-3);
  border: 1px solid var(--border);
  transition: background .15s, border-color .15s;
}
.rz-handle:hover::before, .rz-handle.active::before { background: var(--accent-soft); border-color: var(--accent); }
.rz-handle-x::after, .rz-handle-y::after {
  content: "";
  position: absolute;
  background: var(--muted);
  border-radius: 2px;
}
.rz-handle-x::after { left: 5px; top: 10px; width: 2px; height: 24px; box-shadow: 0 0 0 0; }
.rz-handle-y::after { top: 5px; left: 10px; height: 2px; width: 24px; }

/* demo items */
.demo-item {
  position: relative;
  border-radius: 8px;
  padding: 8px 10px;
  min-width: 44px;
  min-height: 36px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  cursor: pointer;
  border: 1.5px solid transparent;
  background:
    linear-gradient(var(--item-bg, rgba(56,189,248,.14)), var(--item-bg, rgba(56,189,248,.14))),
    var(--panel-2);
  color: var(--text);
  user-select: none;
  transition: border-color .18s, box-shadow .18s, filter .18s;
  overflow: hidden;
}

.demo-item:hover { filter: brightness(1.18); }

.demo-item .item-label {
  font-weight: 650;
  font-size: 12.5px;
  letter-spacing: .02em;
  text-align: center;
  pointer-events: none;
  white-space: nowrap;
}

.demo-item .item-size {
  font-family: var(--mono);
  font-size: 9.5px;
  color: var(--text-dim);
  background: rgba(0, 0, 0, .35);
  border-radius: 4px;
  padding: 0 5px;
  pointer-events: none;
  white-space: nowrap;
}

.demo-item.selected {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft), 0 4px 18px rgba(0,0,0,.35);
  z-index: 2;
}

.demo-item:focus-visible { outline-offset: 1px; }

.canvas-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  color: var(--muted);
  font-size: 13px;
  padding: 60px 40px;
  text-align: center;
  width: 100%;
  min-height: 200px;
}

/* ============================================================
   Code panel
   ============================================================ */

.code-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  flex-wrap: wrap;
}

.code-head h3 {
  margin: 0;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .09em;
  color: var(--muted);
}

.code-block-wrap { position: relative; }

.code-block {
  margin: 0;
  background: var(--panel);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 14px 14px;
  font-family: var(--mono);
  font-size: 11.8px;
  line-height: 1.62;
  overflow-x: auto;
  white-space: pre;
  color: #c9d4e6;
  tab-size: 2;
}

.code-block .c { color: #5d6b85; font-style: italic; }         /* comments */
.code-block .s { color: var(--accent); }                        /* selectors */
.code-block .p { color: #7dd3fc; }                              /* properties */
body[data-mode="grid"] .code-block .p { color: #c4b5fd; }
.code-block .v { color: #f0b98a; }                              /* values */
.code-block .t { color: #9aa7bd; }                              /* tags */
.code-block .a { color: #7dd3fc; }                              /* attrs */

.copy-row { display: flex; flex-wrap: wrap; gap: 6px; }

.btn.copied {
  background: rgba(52, 211, 153, .15) !important;
  border-color: rgba(52, 211, 153, .5) !important;
  color: #34d399 !important;
}

/* ============================================================
   Toast
   ============================================================ */

.toast {
  position: fixed;
  bottom: 22px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--panel-3);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 13px;
  padding: 9px 18px;
  border-radius: 99px;
  box-shadow: var(--shadow);
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s, transform .2s;
  z-index: 100;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

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