/* ═══════════════════════════════════════════════════════════════════════════
   TOUCH SYMPHONY — Stylesheet
   ═══════════════════════════════════════════════════════════════════════════

   Organised in sections from top-down:
     1. Design tokens (CSS custom properties)
     2. Global resets and body layout grid
     3. Header
     4. Stage (canvas area) and overlays
     5. Panel (sidebar)
     6. Panel content modules:
          - Telemetry stat rows
          - Touch list
          - Gesture library
          - Prediction box
          - Advanced controls
     7. Buttons and shared form elements
     8. Modal
     9. Footer
     10. Scrollbars
     11. Sparkline, capability badge, and other atoms

   All colours and fonts go through CSS custom properties (:root variables)
   so global theme changes only require editing one block at the top.

   Mobile rules live inline with each desktop rule as @media (max-width: 860px)
   blocks. The 860px breakpoint was chosen because below that width the
   sidebar panel (320px) consumes too much of the screen to fit comfortably
   alongside the stage.
   ═════════════════════════════════════════════════════════════════════════ */


/* ─── 1. DESIGN TOKENS ────────────────────────────────────────────────────
   Colours are deliberately desaturated (charcoals + dim greys) so the mint
   --accent pops against everything. --warm and --warn are used sparingly
   for status badges and destructive actions. */
:root {
  /* Backgrounds */
  --bg:         #0a0b0f;  /* Page base */
  --bg-raised: #12141a;  /* Header, panel, footer */
  --surface:   #1a1d26;  /* Buttons, inputs, list items */
  --border:    #242834;  /* Hairlines between sections */

  /* Text */
  --text:       #e8ebf0;  /* Primary body text */
  --text-dim:   #8891a3;  /* Labels, secondary text */
  --text-faint: #4a5062;  /* Captions, inactive states */

  /* Accent palette */
  --accent:     #7df5c5;  /* Primary mint — used for interactive highlights */
  --accent-dim: #3a9575;  /* Darker mint for hover/pressed states */
  --warm:       #f5a67d;  /* Amber — used only for the "no sensor" warning */
  --warn:       #f57d7d;  /* Red — destructive actions (recording, reset, delete) */

  /* Font families */
  --mono:    'JetBrains Mono', ui-monospace, monospace;
  --display: 'Fraunces', Georgia, serif;
}


/* ─── 2. GLOBAL RESETS AND BODY LAYOUT ────────────────────────────────────
   A universal box-sizing reset and margin/padding zero. */
* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  /* overflow:hidden prevents accidental page-level scrolling which would
     compete with canvas drag gestures. The panel handles its own scrolling
     on mobile via its own overflow-y:auto. */
  overflow: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
  font-size: 13px;
  -webkit-font-smoothing: antialiased;
  /* touch-action:none stops the browser from handling drags as scrolls or
     zooms — essential so canvas pointer events receive every movement.
     The panel re-enables pan-y explicitly on mobile. */
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

/*
  Body is a CSS Grid container. Desktop layout:
    +----------------------------+---------+
    |         header             | header  |
    +----------------------------+         |
    |                            |         |
    |          stage             |  panel  |
    |                            |         |
    +----------------------------+         |
    |         footer             |         |
    +----------------------------+---------+
  Column 1 is flexible, column 2 is a fixed 320px sidebar.
*/
body {
  display: grid;
  grid-template-columns: 1fr 320px;
  grid-template-rows: auto 1fr auto;
  grid-template-areas:
    "header header"
    "stage  panel"
    "footer panel";
  height: 100vh;
}

/*
  Mobile layout (single column):
    +----------+
    |  header  |
    +----------+
    |  stage   |  ← fixed 55vh so the panel is always partially visible
    +----------+
    |  panel   |  ← 1fr: fills remaining space, scrolls internally
    +----------+
    |  footer  |
    +----------+
  The "1fr" row for panel is critical: without it the panel would expand
  to its content height and get clipped by body's overflow:hidden. With
  it, the panel fills remaining space and handles scrolling internally.
*/
@media (max-width: 860px) {
  body {
    grid-template-columns: 1fr;
    grid-template-rows: auto 55vh 1fr auto;
    grid-template-areas: "header" "stage" "panel" "footer";
  }
}


/* ─── 3. HEADER ───────────────────────────────────────────────────────────
   Two zones (brand, mode tabs) laid out horizontally on desktop,
   vertically on mobile. z-index:10 keeps it above any stage content that
   bleeds over during rendering. */
header {
  grid-area: header;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-raised);
  z-index: 10;
  gap: 12px;
}

@media (max-width: 860px) {
  header {
    flex-direction: column;
    align-items: stretch;   /* So the mode tabs row stretches full width */
    padding: 12px 14px;
    gap: 10px;
  }
}

/* Brand zone: wordmark, tagline, capability badge, all on a baseline. */
.brand {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
}

@media (max-width: 860px) {
  .brand {
    /* Push badge to the right edge on mobile so it doesn't get crushed
       against the wordmark. */
    justify-content: space-between;
    gap: 8px;
  }
}

.brand-mark {
  font-family: var(--display);
  font-weight: 400;
  font-size: 22px;
  letter-spacing: -0.02em;
  font-style: italic;       /* Fraunces italic is characterful but legible */
  white-space: nowrap;
}

/* The <em> inside .brand-mark reads "Symphony" — override the italic
   Fraunces parent back to upright and recolor it accent-green. */
.brand-mark em {
  color: var(--accent);
  font-style: normal;
  font-weight: 500;
}

.brand-tag {
  font-size: 10px;
  color: var(--text-faint);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  white-space: nowrap;
}

/* Hide the tagline on mobile — there simply isn't room. */
@media (max-width: 860px) {
  .brand-tag { display: none; }
}

/* Pressure-capability badge (e.g. "Native Pressure" or "No Sensor").
   Starts neutral; JS adds .native or .synthesised class for colouring. */
.cap-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px 3px 8px;
  border-radius: 12px;
  border: 1px solid var(--border);
  color: var(--text-faint);
  font-size: 9px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  cursor: help;    /* Cursor hints at the title tooltip */
  transition: all 0.3s ease;
}

.cap-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
  opacity: 0.6;
}

/* Green variant: real pressure hardware detected. */
.cap-badge.native {
  color: var(--accent);
  border-color: var(--accent-dim);
}

/* Amber variant: no pressure sensor on this device. */
.cap-badge.synthesised {
  color: var(--warm);
  border-color: var(--warm);
  opacity: 0.8;
}


/* ─── Mode tabs ──
   Pill-grouped buttons. Active button has a raised background and accent
   text. On mobile the group stretches to full width. */
.modes {
  display: flex;
  gap: 4px;
  background: var(--surface);
  padding: 4px;
  border-radius: 8px;
  border: 1px solid var(--border);
  flex-shrink: 0;
}

@media (max-width: 860px) {
  .modes {
    width: 100%;
    justify-content: space-between;
  }
}

.mode-btn {
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-family: var(--mono);
  font-size: 11px;
  padding: 6px 12px;
  border-radius: 5px;
  cursor: pointer;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  transition: all 0.2s;
  flex: 1;              /* Equal width tabs */
  white-space: nowrap;
}

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

.mode-btn.active {
  background: var(--bg-raised);
  color: var(--accent);
  /* Subtle 1px outline so the active tab stays visibly distinct at a glance. */
  box-shadow: 0 0 0 1px var(--border);
}


/* ─── 4. STAGE ────────────────────────────────────────────────────────────
   The canvas-bearing centre column. The grid background is purely CSS —
   drawn via two crossed linear-gradients — so the canvas on top can be
   fully cleared each frame without wiping the grid. This architecture
   guarantees no ghost-pixel buildup from canvas alpha-blending.

   Layer stack (z-index):
      base (grid)       — background on .stage itself
      ::before overlay  — vignette (radial fade to dark corners), z=1
      #canvas           — touch visualisations, z=2
      .stage-hint       — "touch the surface" prompt, z=3
      .stage-overlay    — corner telemetry text, z=5
      .rec-banner       — recording indicator, z=6 */
.stage {
  grid-area: stage;
  position: relative;
  overflow: hidden;
  background: var(--bg);
  /* Two crossed gradients draw a 40×40 px grid of 1px lines. The
     offset position:-1px -1px aligns grid lines with the top-left pixel. */
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 40px 40px;
  background-position: -1px -1px;
}

/* Vignette: fades the grid out towards the corners for a spotlight feel. */
.stage::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, transparent 0%, var(--bg) 100%);
  pointer-events: none;   /* Must not intercept touch events */
  z-index: 1;
}

/* The drawing canvas fills the stage. z-index places it above the vignette. */
#canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 2;
}

/* First-touch hint. Centred, faded, non-interactive. JS adds .hidden
   after the first pointer event and the transition animates it out. */
.stage-hint {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  color: var(--text-faint);
  z-index: 3;
  pointer-events: none;
  transition: opacity 0.4s;
}

.stage-hint.hidden { opacity: 0; }

.stage-hint-big {
  font-family: var(--display);
  font-weight: 300;
  font-style: italic;
  font-size: 36px;
  color: var(--text-dim);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.stage-hint-small {
  font-size: 11px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

/* Corner overlay text (MODE · FREE, ACTIVE · 0, etc.). pointer-events:none
   is critical — these must not block touch events from reaching the canvas. */
.stage-overlay {
  position: absolute;
  z-index: 5;
  pointer-events: none;
  font-family: var(--mono);
  font-size: 10px;
  color: var(--text-faint);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.overlay-tl { top: 16px; left: 20px; }
.overlay-tr { top: 16px; right: 20px; text-align: right; }
.overlay-bl { bottom: 16px; left: 20px; }
.overlay-br { bottom: 16px; right: 20px; text-align: right; }

/* On mobile the stage is smaller so overlays tuck tighter and shrink. */
@media (max-width: 860px) {
  .stage-overlay { font-size: 9px; }
  .overlay-tl { top: 10px; left: 12px; }
  .overlay-tr { top: 10px; right: 12px; }
  .overlay-bl { bottom: 10px; left: 12px; }
  .overlay-br { bottom: 10px; right: 12px; }
  .stage-hint-big { font-size: 26px; }
  .stage-hint-small { font-size: 10px; }
}

/* The accent-coloured live value in each overlay line. */
.overlay-val {
  color: var(--accent);
  font-weight: 500;
}

/* Recording banner — appears during gesture capture. JS toggles .active
   to fade it in. The pulsing dot is animated via keyframes below. */
.rec-banner {
  position: absolute;
  top: 50px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 6;
  background: rgba(245, 125, 125, 0.1);   /* Transparent wash of --warn */
  border: 1px solid var(--warn);
  padding: 6px 14px;
  border-radius: 20px;
  color: var(--warn);
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 8px;
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}

.rec-banner.active { opacity: 1; }

.rec-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--warn);
  animation: pulse 1s ease-in-out infinite;
}

/* pulse keyframes for the recording dot. */
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}


/* ─── 5. PANEL ────────────────────────────────────────────────────────────
   Right-side sidebar on desktop (320px wide), full-width under stage on
   mobile. The panel is the scroll container on mobile — its children must
   not create their own scroll containers (see section 6). */
.panel {
  grid-area: panel;
  background: var(--bg-raised);
  border-left: 1px solid var(--border);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

@media (max-width: 860px) {
  .panel {
    border-left: none;
    border-top: 1px solid var(--border);
    max-height: none;
    /* min-height:0 is required for a flex/grid item to shrink below its
       content size. Without it the panel will always be as tall as its
       content and body's overflow:hidden will clip it. */
    min-height: 0;
    /* Re-enable vertical panning on this region only (body has touch-action:
       none to support canvas drawing). */
    touch-action: pan-y;
    /* iOS-only: enables momentum scrolling. */
    -webkit-overflow-scrolling: touch;
    /* Prevent scroll bubbling up to the body/page. */
    overscroll-behavior: contain;
  }

  .panel-section {
    padding: 14px 16px 12px;
  }

  .panel-title {
    margin-bottom: 10px;
  }

  .stat-row {
    padding: 4px 0;
    font-size: 12px;
  }

  /* IMPORTANT: Mobile layout shouldn't allow .touch-list to have its own scroll
     container. Nested scroll containers on mobile create dead zones
     where drag gestures get captured and never bubble to the panel. */
  .touch-list {
    max-height: none;
    overflow-y: visible;
  }
}

.panel-section {
  padding: 20px 20px 16px;
  border-bottom: 1px solid var(--border);
}

.panel-section:last-child {
  border-bottom: none;
  /* Extra bottom padding so the last control isn't cut off by browser
     UI (address bar, nav, home indicator). */
  padding-bottom: 40px;
}

@media (max-width: 860px) {
  .panel-section:last-child {
    padding-bottom: 80px;
  }
}


/* ─── 6. PANEL CONTENT MODULES ────────────────────────────────────────── */

/* Section title row ("Live Telemetry", "Pointer Stream", etc.). Small
   caps style with the title on the left and an optional badge on the right. */
.panel-title {
  font-size: 9px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--text-faint);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Variant for clickable titles (used by the Gesture Library collapse toggle). */
.panel-title.clickable {
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  transition: color 0.15s;
}

.panel-title.clickable:hover { color: var(--text-dim); }

/* Small ▾ chevron next to the collapsible title. Rotates when collapsed. */
.collapse-chevron {
  display: inline-block;
  transition: transform 0.2s ease;
  margin-right: 4px;
  color: var(--text-dim);
}

.collapse-chevron.collapsed {
  transform: rotate(-90deg);
}

/* ── Collapsible body ──
   CRITICAL BUG-FIX HISTORY: This rule had overflow:hidden + fixed
   max-height on the EXPANDED state. On mobile browsers, such a
   container inside a scrolling parent becomes a touch dead zone —
   drag gestures get captured and never bubble to the panel scroller,
   making content below unreachable. Fix: only apply overflow:hidden
   when collapsed or during the transition. In the expanded steady
   state, the element is visually and behaviourally transparent. */
.collapsible-body {
  transition: max-height 0.25s ease, opacity 0.2s ease;
  max-height: none;
  opacity: 1;
}

.collapsible-body.collapsed {
  overflow: hidden;
  max-height: 0;
  opacity: 0;
}

/* Applied briefly during the collapse animation so content doesn't spill
   out while max-height is transitioning. Removed by JS once animation
   completes. */
.collapsible-body.animating {
  overflow: hidden;
  max-height: 2000px;
}

/* Small rounded pill badge in the top-right of a panel title. */
.panel-title-badge {
  font-size: 9px;
  padding: 2px 8px;
  border-radius: 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-dim);
  letter-spacing: 0.1em;
}

/* "LIVE" variant — glows accent-green. */
.panel-title-badge.live {
  color: var(--accent);
  border-color: var(--accent-dim);
}


/* ── Telemetry stat row ──
   Label on the left, tabular-num value on the right. */
.stat-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 6px 0;
  font-size: 12px;
}

.stat-label {
  color: var(--text-dim);
  font-size: 11px;
}

.stat-value {
  color: var(--text);
  /* tabular-nums keeps digits the same width so rapidly-changing
     numbers don't wobble horizontally. */
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

.stat-value.accent { color: var(--accent); }


/* ── Touch list (live pointer rows) ── */
.touch-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 28px;
}

.touch-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 8px 10px;
  font-size: 10px;
  display: grid;
  grid-template-columns: auto 1fr auto;   /* id | coords | pressure bar */
  gap: 10px;
  align-items: center;
  animation: fadeIn 0.15s ease;
}

/* fade-in animation for new touch rows. */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-2px); }
  to   { opacity: 1; transform: translateY(0); }
}

.touch-id {
  color: var(--accent);
  font-weight: 500;
  font-size: 10px;
}

.touch-coords {
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
}

/* Mini pressure bar. The fill element is width-animated by JS. */
.touch-pressure-bar {
  width: 40px;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}

.touch-pressure-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  transition: width 0.1s;
}

.touch-empty {
  color: var(--text-faint);
  font-size: 10px;
  font-style: italic;
  text-align: center;
  padding: 8px;
}


/* ── Gesture library ── */
.gesture-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
  max-height: 140px;
  overflow-y: auto;
  margin-top: 8px;
  overscroll-behavior: contain;
}

@media (max-width: 860px) {
  /* On mobile, the whole panel scrolls. Making the inner list its own
     scroll container traps the outer drag gesture. Let it flow. */
  .gesture-list {
    max-height: none;
    overflow-y: visible;
  }
}

.gesture-item {
  display: grid;
  grid-template-columns: auto 1fr auto;   /* swatch | name | remove button */
  gap: 8px;
  align-items: center;
  padding: 6px 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 10px;
}

/* Mini preview of the saved gesture shape (rendered as a data-URL image). */
.gesture-swatch {
  width: 28px;
  height: 28px;
  background: var(--bg);
  border-radius: 3px;
  border: 1px solid var(--border);
}

.gesture-name {
  color: var(--text);
}

.gesture-remove {
  background: none;
  border: none;
  color: var(--text-faint);
  cursor: pointer;
  font-family: var(--mono);
  font-size: 12px;
  padding: 0 4px;
}

.gesture-remove:hover { color: var(--warn); }

.gesture-empty {
  color: var(--text-faint);
  font-size: 10px;
  font-style: italic;
  padding: 8px 0;
  text-align: center;
}


/* ── Prediction display (classify mode) ── */
.predict-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px;
  text-align: center;
  margin-top: 10px;
}

.predict-label {
  font-family: var(--display);
  font-size: 20px;
  font-weight: 500;
  color: var(--accent);
  margin-bottom: 4px;
  font-style: italic;
}

/* Dim + italic variant for "Draw to classify" / "Unknown gesture" states. */
.predict-label.none {
  color: var(--text-faint);
  font-style: italic;
}

.predict-confidence {
  font-size: 10px;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.predict-bar {
  width: 100%;
  height: 3px;
  background: var(--border);
  border-radius: 2px;
  margin-top: 8px;
  overflow: hidden;
}

.predict-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  transition: width 0.2s;
}


/* ── Advanced controls ── */

/* The outer toggle button that reveals/hides the group. Dashed border
   distinguishes it from regular action buttons. */
.adv-toggle {
  background: transparent;
  border: 1px dashed var(--border);
  color: var(--text-faint);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
  width: 100%;
  transition: all 0.15s;
}

.adv-toggle:hover {
  color: var(--accent);
  border-color: var(--accent-dim);
  border-style: solid;
}

/* The expanded controls group. display:none by default; .open class from
   JS reveals it. */
.adv-group {
  display: none;
  margin-top: 12px;
}

.adv-group.open { display: block; }

/* A subgroup of related sliders (e.g. "Heatmap Accumulation"). Dashed
   bottom border separates them visually. */
.adv-subgroup {
  margin-bottom: 14px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--border);
}

.adv-subgroup:last-of-type {
  border-bottom: none;
  margin-bottom: 4px;
}

.adv-subtitle {
  font-size: 9px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-faint);
  margin-bottom: 8px;
}

/* Container for one slider + its label + readout + hint. */
.adv-ctrl {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 10px;
}

.adv-ctrl-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 10px;
}

.adv-ctrl-label {
  color: var(--text-dim);
}

.adv-ctrl-val {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

/* Range slider — custom styled because default browser sliders look
   jarring against a dark theme. WebKit and Gecko need separate rules. */
.adv-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 3px;
  background: var(--border);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
  margin: 2px 0;
}

.adv-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  /* Double border: the outer bg-raised ring + inner accent halo */
  border: 2px solid var(--bg-raised);
  box-shadow: 0 0 0 1px var(--accent);
}

.adv-slider::-moz-range-thumb {
  width: 12px;
  height: 12px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid var(--bg-raised);
  box-shadow: 0 0 0 1px var(--accent);
}

/* Small italic description under each slider. */
.adv-hint {
  font-size: 9px;
  color: var(--text-faint);
  font-style: italic;
  line-height: 1.4;
  margin-top: 2px;
}


/* ─── 7. BUTTONS AND SHARED FORM ELEMENTS ─────────────────────────────── */

.btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s;
  width: 100%;
}

.btn:hover {
  background: var(--border);
  border-color: var(--text-dim);
}

/* Subtle press effect. */
.btn:active { transform: translateY(1px); }

/* Primary action (green fill). Used for "Save" in the modal. */
.btn-primary {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--bg);
  font-weight: 500;
}

.btn-primary:hover {
  background: var(--accent);
  color: var(--bg);
}

/* Warning/destructive variant (red outline). Used for "Reset". */
.btn-warn {
  background: transparent;
  border-color: var(--warn);
  color: var(--warn);
}

.btn-warn:hover {
  background: var(--warn);
  color: var(--bg);
}

/* Two-column button grid for paired action buttons. */
.btn-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-top: 10px;
}


/* ─── 8. MODAL (gesture naming dialog) ──────────────────────────────────
   Full-screen dim backdrop with a centred card. JS adds .active on the
   backdrop to show it. Clicking outside the card closes it. */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(10, 11, 15, 0.85);
  backdrop-filter: blur(4px);      /* Frosted glass behind the modal */
  z-index: 100;
  display: none;
  align-items: center;
  justify-content: center;
}

.modal-backdrop.active { display: flex; }

.modal {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  width: 90%;
  max-width: 360px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.5);
}

.modal h3 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 20px;
  margin-bottom: 6px;
}

.modal p {
  color: var(--text-dim);
  font-size: 11px;
  margin-bottom: 16px;
  line-height: 1.5;
}

.modal input {
  width: 100%;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--mono);
  font-size: 13px;
  padding: 10px 12px;
  border-radius: 6px;
  margin-bottom: 12px;
}

.modal input:focus {
  outline: none;
  border-color: var(--accent);
}

.modal-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}


/* ─── 9. FOOTER ───────────────────────────────────────────────────────── */
footer {
  grid-area: footer;
  padding: 10px 24px;
  border-top: 1px solid var(--border);
  background: var(--bg-raised);
  font-size: 10px;
  color: var(--text-faint);
  display: flex;
  justify-content: space-between;
  letter-spacing: 0.08em;
}

footer a {
  color: var(--text-dim);
  text-decoration: none;
  transition: color 0.2s;
}

footer a:hover { color: var(--accent); }


/* ─── 10. SCROLLBARS ──────────────────────────────────────────────────── */
/* WebKit-only thin dark scrollbars. */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-faint); }


/* ─── 11. SPARKLINE ───────────────────────────────────────────────────── */
/* Canvas element inside the telemetry section. JS draws pressure history
   on it; CSS just sets the container box. */
.sparkline {
  width: 100%;
  height: 40px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  margin-top: 6px;
}