/* ════════════════════════════════════════════════════════════════
   Sheet Metal Bend Radius Calculator — press-brake bench UI
   (layout synthesised from the Refrigeration Cycle + Morse Test rigs)
   ════════════════════════════════════════════════════════════════ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --bg: #0d1117;
  --surface: #161b27;
  --surface2: #1f2535;
  --border: #2a3050;
  --accent: #d4922a;
  --accent-lo: rgba(212,146,42,.22);
  --green: #3ddc84;
  --red: #ff5555;
  --gold: #f5c842;
  --warn: #ff7043;
  --metal: #9fb2c8;
  --text: #dde3f0;
  --text-dim: #6b7a99;
  --font: 'Segoe UI', system-ui, sans-serif;
  --mono: 'Courier New', monospace;
  --radius: 12px;
}

body { background: var(--bg); color: var(--text); font-family: var(--font); min-height: 100vh; padding: 0 16px 60px; line-height: 1.5; }
#app { max-width: 1320px; margin: 0 auto; }

header { text-align: center; margin: 14px 0 16px; }
header h1 {
  font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 700;
  background: linear-gradient(120deg, #d4922a 0%, #f5cf6e 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.subtitle { color: var(--text-dim); font-size: .92rem; margin-top: 4px; }

/* ── Controls bar ── */
.controls-bar {
  display: flex; flex-wrap: wrap; gap: 12px; align-items: center;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 10px 14px; margin-bottom: 14px;
}
.ctrl-group { display: flex; align-items: center; gap: 8px; }
.ctrl-label { font-size: .72rem; color: var(--text-dim); font-weight: 700; text-transform: uppercase; letter-spacing: .05em; white-space: nowrap; }
.pill-tabs { display: inline-flex; flex-wrap: wrap; background: var(--bg); border-radius: 8px; padding: 3px; gap: 2px; }
.pill { background: transparent; border: none; color: var(--text-dim); padding: 7px 15px; border-radius: 6px; cursor: pointer; font-size: .82rem; font-weight: 600; transition: all .15s; min-height: 40px; }
.pill:hover:not(.active) { color: var(--text); background: var(--surface2); }
.pill.active { background: var(--accent); color: #fff; box-shadow: 0 0 10px var(--accent-lo); }

.unit-toggle { display: inline-flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
.unit-opt { padding: 7px 14px; border: none; background: var(--surface2); color: var(--text-dim); font-size: .82rem; font-weight: 600; cursor: pointer; transition: all .15s; min-height: 40px; }
.unit-opt + .unit-opt { border-left: 1px solid var(--border); }
.unit-opt.active { background: var(--accent); color: #fff; font-weight: 700; }
.unit-opt:not(.active):hover { background: var(--border); color: var(--text); }
.btn-guide { padding: 8px 16px; border-radius: 8px; cursor: pointer; font-size: .82rem; font-weight: 700; background: var(--gold); color: #1a1a2e; text-decoration: none; transition: filter .15s; }
.btn-guide:hover { filter: brightness(1.08); }

/* ── Buttons ── */
.btn { padding: 8px 15px; border-radius: 7px; border: 1px solid var(--border); background: var(--surface2); color: var(--text); cursor: pointer; font-size: .82rem; font-weight: 600; transition: all .15s; min-height: 40px; display: inline-flex; align-items: center; gap: 5px; }
.btn:hover { border-color: var(--accent); }
.btn:active { transform: scale(.96); }
.btn:disabled { opacity: .4; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn-primary:hover { filter: brightness(1.1); box-shadow: 0 0 10px var(--accent-lo); }
.btn-ghost { background: transparent; }
.btn-calc { background: linear-gradient(135deg, #e0a23a, #b9781d); color: #fff; border-color: #a96f17; font-weight: 700; }
.btn-calc:hover { filter: brightness(1.1); box-shadow: 0 0 12px var(--accent-lo); }

/* ── Canvas row ── */
.canvas-row { display: grid; grid-template-columns: 1.12fr 1fr; gap: 14px; margin-bottom: 14px; }
.canvas-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 10px; overflow-x: clip; position: relative; display: flex; flex-direction: column; }
.canvas-card canvas { display: block; width: 100%; height: auto; background: #0a0d14; border-radius: 8px; touch-action: none; cursor: grab; }
.canvas-card canvas:active { cursor: grabbing; }

/* ── Drawing-layer toggles under cross-section ── */
.mc-toggles { display: flex; flex-wrap: wrap; align-items: center; gap: 5px 10px; padding: 8px 4px 2px; border-top: 1px solid var(--border); margin-top: 8px; }
.mc-tog-label { font-size: .66rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-dim); white-space: nowrap; }
.cv-tog { display: inline-flex; align-items: center; gap: 5px; font-size: .73rem; color: var(--text-dim); cursor: pointer; user-select: none; padding: 3px 6px; border-radius: 5px; }
.cv-tog:hover { background: rgba(255,255,255,.05); color: var(--text); }
.cv-tog input { accent-color: var(--accent); width: 14px; height: 14px; cursor: pointer; }

/* ── Chart tabs (right view selector) ── */
.chart-tabs { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin-top: 8px; padding: 6px 8px; background: var(--surface2); border: 1px solid var(--border); border-radius: 8px; }
.chart-tabs-label { font-size: .66rem; color: var(--text-dim); font-weight: 700; text-transform: uppercase; letter-spacing: .06em; margin-right: 4px; }
.chart-tab { background: transparent; border: 1px solid var(--border); color: var(--text-dim); border-radius: 6px; padding: 5px 11px; font-size: .76rem; font-weight: 600; cursor: pointer; transition: all .15s; }
.chart-tab:hover { color: var(--text); border-color: var(--accent); }
.chart-tab.active { background: var(--accent); color: #fff; border-color: var(--accent); box-shadow: 0 0 6px var(--accent-lo); }

/* ── Graph badges ── */
.graph-badges { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 10px; }
.graph-badge { display: inline-flex; align-items: center; gap: 6px; padding: 5px 11px; background: var(--surface2); border: 1px solid var(--border); border-radius: 999px; font-size: .74rem; color: var(--text-dim); }
.graph-badge-val { font-family: var(--mono); font-weight: 700; color: var(--text); }
.rb-dot { width: 8px; height: 8px; border-radius: 50%; flex-shrink: 0; }
.rb-u { font-size: .66rem; color: var(--text-dim); }
.status-badge { font-weight: 700; text-transform: uppercase; letter-spacing: .05em; font-size: .72rem; }
.status-badge.ok { background: rgba(61,220,132,.15); color: var(--green); border-color: rgba(61,220,132,.35); }
.status-badge.bad { background: rgba(255,85,85,.15); color: var(--red); border-color: rgba(255,85,85,.35); }

/* ── Canvas action bar ── */
.canvas-action-bar { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin-top: 10px; padding-top: 10px; border-top: 1px solid var(--border); }

/* ── Setup form in the flat-pattern card (under Show Calculations) ── */
.flat-setup { margin-top: 10px; padding-top: 12px; border-top: 1px solid var(--border); display: flex; flex-direction: column; gap: 9px; }
.flat-setup .ctrl-mat { display: flex; align-items: center; gap: 10px; width: 100%; }
.flat-setup .ctrl-mat > .ctrl-label { width: 62px; flex-shrink: 0; }
.flat-setup .mat-sel { flex: 1; min-width: 0; }
.flat-setup .ctrl-selects { display: flex; flex-direction: column; gap: 9px; }
.flat-setup .mini-field { display: flex; align-items: center; gap: 10px; width: 100%; }
.flat-setup .mini-field > .ctrl-label { width: 62px; flex-shrink: 0; }
.flat-setup .mini-field .mini-sel { flex: 1; min-width: 0; }

/* ── Control deck ── */
.sim-controls { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 14px; margin-bottom: 14px; }
.ctrl-top-row { display: flex; flex-wrap: wrap; gap: 12px 18px; align-items: center; padding-bottom: 10px; margin-bottom: 12px; border-bottom: 1px solid var(--border); }
.ctrl-mat { align-items: center; }
.mat-sel { min-width: 200px; min-height: 38px; }
.ctrl-selects { display: flex; gap: 12px; flex-wrap: wrap; }
.mini-field { display: inline-flex; align-items: center; gap: 6px; }
.mini-sel, .mini-num {
  padding: 6px 9px; border: 1px solid var(--border); border-radius: 7px;
  background: var(--surface2); color: var(--text); font-size: .78rem; font-weight: 600;
  cursor: pointer; outline: none; min-height: 34px;
}
.mini-num { width: 64px; font-family: var(--mono); color: var(--accent); text-align: center; -moz-appearance: textfield; }
.mini-num::-webkit-outer-spin-button, .mini-num::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.mini-num:disabled { opacity: .4; }
.mini-sel:focus, .mini-num:focus { border-color: var(--accent); }
.mini-sel option { background: #141a2e; }

/* ── Material chips ── */
.mat-strip { display: flex; flex-wrap: wrap; gap: 5px; }
.mat-pill { display: inline-flex; align-items: center; gap: 6px; padding: 5px 12px; border: 1px solid var(--border); border-radius: 999px; background: var(--surface2); color: var(--text-dim); cursor: pointer; font-size: .75rem; font-weight: 600; transition: all .15s; white-space: nowrap; }
.mat-pill:hover:not(.active) { color: var(--text); border-color: var(--accent); background: rgba(255,255,255,.05); }
.mat-pill.active { background: var(--accent); border-color: var(--accent); color: #fff; box-shadow: 0 0 10px var(--accent-lo); }
.mat-custom { border-style: dashed; color: var(--accent); }

/* ── Slider groups (drag + stepper) ── */
.slider-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 10px; }
.sim-slider-group { display: flex; flex-direction: column; gap: 7px; min-width: 0; background: var(--bg); border: 1px solid var(--border); border-radius: 8px; padding: 8px 10px 10px; }
.sim-slider-header { display: flex; align-items: center; gap: 6px; }
.sim-slider-label { font-size: .72rem; font-weight: 700; color: var(--text-dim); flex: 1; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.stepper { display: flex; align-items: stretch; flex-shrink: 0; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; background: var(--bg); height: 26px; }
.step-btn { width: 24px; min-width: 24px; border: none; background: var(--surface2); color: var(--text-dim); font-size: .95rem; font-weight: 700; cursor: pointer; transition: all .15s; display: flex; align-items: center; justify-content: center; padding: 0; }
.step-btn:hover { background: var(--accent-lo); color: var(--accent); }
.step-btn:active { background: var(--accent); color: #fff; }
.step-input { width: 50px; flex: none; border: none; background: var(--bg); color: var(--accent); font-family: var(--mono); font-size: .78rem; font-weight: 700; text-align: center; outline: none; padding: 0; height: 100%; border-left: 1px solid var(--border); border-right: 1px solid var(--border); -moz-appearance: textfield; }
.step-input:focus { background: var(--surface2); }
.step-input::-webkit-outer-spin-button, .step-input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.sim-unit-badge { display: inline-flex; align-items: center; padding: 0 7px; height: 22px; border-radius: 5px; background: var(--accent-lo); color: var(--accent); font-size: .64rem; font-weight: 700; flex-shrink: 0; }
.sim-slider { width: 100%; -webkit-appearance: none; appearance: none; height: 6px; background: rgba(255,255,255,.12); border-radius: 3px; outline: none; border: 1px solid rgba(255,255,255,.08); cursor: pointer; padding: 5px 0; box-sizing: content-box; }
.sim-slider::-webkit-slider-runnable-track { height: 6px; border-radius: 3px; background: linear-gradient(to right, var(--accent-lo), rgba(255,255,255,.12)); }
.sim-slider::-webkit-slider-thumb { -webkit-appearance: none; width: 17px; height: 17px; margin-top: -6px; border-radius: 50%; background: var(--accent); cursor: grab; box-shadow: 0 0 8px var(--accent-lo); border: 2px solid rgba(255,255,255,.25); }
.sim-slider::-moz-range-track { height: 6px; border-radius: 3px; background: linear-gradient(to right, var(--accent-lo), rgba(255,255,255,.12)); }
.sim-slider::-moz-range-thumb { width: 15px; height: 15px; border: 2px solid rgba(255,255,255,.25); border-radius: 50%; background: var(--accent); cursor: grab; }

/* Out-of-range (radius below material minimum) indicator on the slider itself */
.sim-slider-group.danger { border-color: var(--red); box-shadow: inset 0 0 0 1px rgba(255,85,85,.45); }
.sim-slider-group.danger .sim-slider-label { color: var(--red); }
.sim-slider-group.danger .sim-unit-badge { background: rgba(255,85,85,.18); color: var(--red); }
.sim-slider-group.danger .step-input { color: var(--red); }
.sim-slider-group.danger .sim-slider::-webkit-slider-runnable-track { background: linear-gradient(to right, rgba(255,85,85,.55), rgba(255,85,85,.12)); }
.sim-slider-group.danger .sim-slider::-webkit-slider-thumb { background: var(--red); box-shadow: 0 0 8px rgba(255,85,85,.6); border-color: rgba(255,255,255,.35); }
.sim-slider-group.danger .sim-slider::-moz-range-track { background: linear-gradient(to right, rgba(255,85,85,.55), rgba(255,85,85,.12)); }
.sim-slider-group.danger .sim-slider::-moz-range-thumb { background: var(--red); }
.r-min-flag { font-size: .66rem; font-weight: 700; color: var(--red); min-height: 0; line-height: 1.3; }
.r-min-flag:empty { display: none; }

/* ── Dashboard ── */
.readout-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 10px; padding: 14px 16px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); margin-bottom: 14px; }
.readout-card { background: var(--surface2); border: 1px solid var(--border); border-radius: 9px; padding: 11px 10px; text-align: center; position: relative; }
.readout-card.rc-flat { border-color: var(--gold); box-shadow: 0 0 0 1px rgba(245,200,66,.25) inset; }
.readout-label { font-size: .65rem; text-transform: uppercase; letter-spacing: .04em; color: var(--text-dim); margin-bottom: 5px; font-weight: 600; }
.readout-value { font-family: var(--mono); font-size: 1.12rem; font-weight: 700; color: var(--accent); }
.readout-card.rc-flat .readout-value { color: var(--gold); }
.readout-value.warn { color: var(--red); }
.readout-unit { font-size: .66rem; color: var(--text-dim); margin-top: 3px; }

/* ── On-canvas KaTeX equation overlay ── */
.bend-eq { position: absolute; left: 18px; top: 60px; max-width: 44%; z-index: 2; pointer-events: none; background: rgba(10,13,20,.55); border-left: 3px solid var(--accent); border-radius: 8px; padding: 9px 12px 11px; box-shadow: 0 6px 18px rgba(0,0,0,.3); }
.bend-eq .eq-cap { font-size: .62rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: .07em; margin-bottom: 5px; font-weight: 700; }
.bend-eq .katex { color: #e1e7f3; }
.bend-eq .katex-display { margin: 5px 0; text-align: left; }
.bend-eq .katex-display:last-child { margin-bottom: 0; }

/* ── Floating Reset on the cross-section (bottom-right) ── */
.canvas-reset-fab {
  position: absolute; right: 16px; top: 320px; z-index: 3;
  display: inline-flex; align-items: center; gap: 5px;
  padding: 7px 13px; border-radius: 8px;
  background: rgba(10,13,20,.62); border: 1px solid var(--border);
  color: var(--text); font-size: .76rem; font-weight: 600; cursor: pointer;
  backdrop-filter: blur(2px); transition: all .15s;
}
.canvas-reset-fab:hover { border-color: var(--accent); color: #fff; background: var(--accent-lo); }
.canvas-reset-fab:active { transform: scale(.95); }
@media (max-width: 500px) { .canvas-reset-fab { right: 8px; bottom: 64px; padding: 6px 10px; } }

/* ── Floating mm/inch toggle on the cross-section (bottom-left) ── */
.canvas-unit-toggle {
  position: absolute; left: 16px; top: 320px; z-index: 3;
  display: inline-flex; border-radius: 8px; overflow: hidden;
  background: rgba(10,13,20,.62); border: 1px solid var(--border);
  backdrop-filter: blur(2px); box-shadow: 0 4px 12px rgba(0,0,0,.3);
}
.canvas-unit-toggle .unit-opt {
  padding: 6px 13px; min-height: 0; border: none; background: transparent;
  color: var(--text-dim); font-size: .76rem; font-weight: 700; cursor: pointer;
  transition: background .15s, color .15s; line-height: 1.3;
}
.canvas-unit-toggle .unit-opt + .unit-opt { border-left: 1px solid var(--border); }
.canvas-unit-toggle .unit-opt.active { background: var(--accent); color: #fff; }
.canvas-unit-toggle .unit-opt:not(.active):hover { background: rgba(255,255,255,.06); color: var(--text); }
@media (max-width: 500px) { .canvas-unit-toggle { left: 8px; } .canvas-unit-toggle .unit-opt { padding: 5px 10px; } }

/* ── Vertical bend-angle slider on the cross-section ── */
.angle-slider { position: absolute; right: 14px; top: 56px; z-index: 3; display: flex; flex-direction: column; align-items: center; gap: 6px; background: rgba(10,13,20,.5); border: 1px solid var(--border); border-radius: 12px; padding: 9px 6px; }
.angle-slider .as-val { font: 700 .8rem var(--mono); color: var(--accent); }
.angle-slider .as-cap { font-size: .56rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: .05em; text-align: center; line-height: 1.2; }
.as-rail { position: relative; width: 30px; height: 188px; }
.as-rail input[type="range"] { position: absolute; left: 50%; top: 50%; width: 188px; height: 22px; margin: 0; transform: translate(-50%,-50%) rotate(-90deg); -webkit-appearance: none; appearance: none; background: transparent; cursor: pointer; }
.as-rail input[type="range"]:focus { outline: none; }
.as-rail input[type="range"]::-webkit-slider-runnable-track { height: 6px; border-radius: 3px; background: linear-gradient(to right, var(--accent-lo), rgba(255,255,255,.12)); border: 1px solid rgba(255,255,255,.1); }
.as-rail input[type="range"]::-webkit-slider-thumb { -webkit-appearance: none; width: 20px; height: 20px; margin-top: -8px; border-radius: 50%; background: var(--accent); cursor: pointer; box-shadow: 0 0 8px var(--accent-lo); border: 2px solid rgba(255,255,255,.25); }
.as-rail input[type="range"]::-moz-range-track { height: 6px; border-radius: 3px; background: linear-gradient(to right, var(--accent-lo), rgba(255,255,255,.12)); border: 1px solid rgba(255,255,255,.1); }
.as-rail input[type="range"]::-moz-range-thumb { width: 18px; height: 18px; border: 2px solid rgba(255,255,255,.25); border-radius: 50%; background: var(--accent); cursor: pointer; box-shadow: 0 0 8px var(--accent-lo); }

/* ── Learning panels (KaTeX) ── */
.learn-panels { padding: 14px; background: linear-gradient(180deg, rgba(30,38,66,.5), rgba(20,26,46,.5)); border: 1px solid var(--border); border-radius: 12px; margin-bottom: 14px; }
.learn-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; padding-bottom: 10px; border-bottom: 1px solid var(--border); margin-bottom: 12px; }
.learn-head-title { font-size: .95rem; font-weight: 700; color: #e1e7f3; }
.learn-head-actions { display: flex; gap: 8px; }
.learn-toggle-all { padding: 5px 12px; background: var(--accent-lo); border: 1px solid rgba(212,146,42,.4); color: #f0c989; border-radius: 6px; font-size: .76rem; font-weight: 600; cursor: pointer; transition: all .15s; }
.learn-toggle-all:hover { background: rgba(212,146,42,.28); color: #e1e7f3; }
.learn-card-collapsible { border: 1px solid var(--border); border-radius: 10px; background: rgba(13,17,30,.5); margin-bottom: 10px; overflow: hidden; }
.learn-card-collapsible:last-child { margin-bottom: 0; }
.learn-card-collapsible[open] { border-color: rgba(212,146,42,.45); }
.learn-card-collapsible > summary { list-style: none; cursor: pointer; padding: 10px 14px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; font-size: .88rem; font-weight: 700; color: #e1e7f3; user-select: none; }
.learn-card-collapsible > summary::-webkit-details-marker { display: none; }
.learn-card-collapsible > summary::marker { content: ''; }
.learn-card-collapsible > summary:hover { background: rgba(212,146,42,.1); }
.learn-card-collapsible > summary::after { content: '▾'; margin-left: auto; color: var(--text-dim); font-size: .78rem; transition: transform .2s; }
.learn-card-collapsible[open] > summary::after { transform: rotate(180deg); color: var(--accent); }
.lp-badge { display: inline-flex; align-items: center; justify-content: center; width: 22px; height: 22px; border-radius: 6px; background: var(--accent-lo); font-size: .9rem; flex-shrink: 0; }
.lp-sub { color: var(--text-dim); font-weight: 500; font-size: .76rem; }
.learn-body-card { padding: 12px 14px 14px; }
.eq-line { margin: 6px 0; font-size: .92rem; color: #e1e7f3; line-height: 1.55; }
.coach-list { margin: 0; padding: 0 0 0 4px; list-style: none; }
.coach-list li { position: relative; padding: 5px 0 5px 18px; font-size: .84rem; color: var(--text-dim); line-height: 1.5; }
.coach-list li::before { content: '›'; position: absolute; left: 0; top: 4px; color: var(--accent); font-weight: 700; }
.coach-list strong { color: #e1e7f3; }

/* ── Step-by-step ── */
.step-content .calc-step { display: flex; gap: 10px; padding: 8px 0; border-bottom: 1px solid rgba(42,48,80,.5); }
.step-content .calc-step:last-child { border-bottom: none; }
.cs-num { flex: 0 0 22px; height: 22px; border-radius: 50%; background: var(--accent); color: #fff; font-size: .72rem; font-weight: 700; display: flex; align-items: center; justify-content: center; }
.cs-body { flex: 1; min-width: 0; }
.cs-title { font-size: .78rem; font-weight: 700; color: var(--text-dim); margin-bottom: 2px; }
.cs-text { font-size: .8rem; line-height: 1.5; color: var(--text); }
.cs-text code { font-family: var(--mono); background: rgba(255,255,255,.06); padding: 1px 5px; border-radius: 4px; color: var(--accent); }

/* ── Explore cards ── */
.explore-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 12px; }
.ex-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px; }
.ex-card h4 { font-size: .95rem; color: var(--accent); margin-bottom: 6px; }
.ex-card p { font-size: .84rem; line-height: 1.55; color: var(--text-dim); margin-bottom: 6px; }
.ex-card .ex-formula { font-family: var(--mono); font-size: .84rem; color: var(--gold); background: var(--surface2); border-left: 3px solid var(--accent); border-radius: 4px; padding: 7px 10px; margin: 6px 0; }
.ex-card .ex-note { font-size: .78rem; color: var(--gold); font-style: italic; background: rgba(245,200,66,.08); border-radius: 5px; padding: 6px 9px; }
.ex-card code { font-family: var(--mono); color: var(--accent); }

/* ── Practice & Quiz ── */
.question-panel, .quiz-result { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; margin-bottom: 14px; }
.pp-prompt, .qp-prompt { font-size: 1rem; color: var(--text); line-height: 1.6; margin-bottom: 14px; }
.qp-header { font-size: .82rem; color: var(--text-dim); font-weight: 700; margin-bottom: 10px; }
.q-designation { font-family: var(--mono); font-size: 1.4rem; font-weight: 700; color: #fff; margin-bottom: 12px; }
.pp-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; }
.pp-field { display: flex; align-items: center; gap: 8px; }
.pp-field label { width: 110px; font-size: .8rem; color: var(--text-dim); font-weight: 600; flex-shrink: 0; }
.pp-unit { font-size: .76rem; color: var(--text-dim); }
.qi-input { background: var(--surface2); border: 1.5px solid var(--border); border-radius: 7px; padding: 8px 11px; color: var(--text); font-family: var(--mono); font-size: .9rem; flex: 1; min-width: 0; transition: border-color .15s; }
.qi-input:focus { outline: none; border-color: var(--accent); }
.qi-input.pi-ok { border-color: var(--green); background: rgba(61,220,132,.06); }
.qi-input.pi-err { border-color: var(--red); background: rgba(255,85,85,.06); }
.pp-actions { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin-top: 14px; }
.pbar-score { margin-left: auto; font-size: .85rem; color: var(--text-dim); font-weight: 600; }
.feedback { margin-top: 12px; padding: 10px 14px; border-radius: 8px; font-size: .86rem; font-weight: 600; display: none; }
.feedback.show, .feedback.ok, .feedback.err { display: block; }
.feedback.ok { background: rgba(61,220,132,.12); color: var(--green); border-left: 3px solid var(--green); }
.feedback.err { background: rgba(255,85,85,.12); color: var(--red); border-left: 3px solid var(--red); }
.solution-panel { background: var(--surface); border: 1px solid var(--accent); border-radius: var(--radius); padding: 14px; margin-top: 12px; font-size: .86rem; }
.solution-panel h4 { color: var(--accent); margin-bottom: 8px; }
.sol-row { display: flex; justify-content: space-between; padding: 3px 0; font-size: .84rem; }
.sol-row span:first-child { color: var(--text-dim); }
.sol-row span:last-child { font-family: var(--mono); }
.sol-divider { height: 1px; background: var(--border); margin: 6px 0; }
.q-section { margin: 12px 0; }
.q-label { font-size: .82rem; color: var(--text-dim); font-weight: 600; margin-bottom: 6px; }
.answer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px; }
.answer-opt { background: var(--surface2); border: 1.5px solid var(--border); border-radius: 8px; padding: 11px 14px; color: var(--text); cursor: pointer; font-size: .88rem; font-weight: 600; transition: all .15s; text-align: center; min-height: 44px; }
.answer-opt:hover:not(:disabled) { border-color: var(--accent); }
.answer-opt.selected { border-color: var(--accent); background: var(--accent-lo); color: #fff; }
.answer-opt.q-ok { border-color: var(--green); background: rgba(61,220,132,.15); color: var(--green); }
.answer-opt.q-err { border-color: var(--red); background: rgba(255,85,85,.1); color: var(--red); }
.qr-header { text-align: center; margin-bottom: 14px; }
.qr-score { font-size: 2rem; font-weight: 700; font-family: var(--mono); color: var(--accent); }
.qr-score.perfect { color: var(--gold); } .qr-score.good { color: var(--green); } .qr-score.poor { color: var(--red); }
.qr-stars { font-size: 1.5rem; margin: 8px 0; color: var(--gold); }
.qr-verdict { color: var(--text-dim); font-size: .9rem; }
.qr-rows { margin-bottom: 14px; }
.qr-row { display: grid; grid-template-columns: 30px 1fr 1fr 1fr 24px; gap: 8px; align-items: center; padding: 7px 8px; border-left: 3px solid transparent; border-radius: 5px; font-size: .78rem; margin-bottom: 5px; background: rgba(255,255,255,.02); }
.qr-row.ok { border-left-color: var(--green); } .qr-row.err { border-left-color: var(--red); }
.qr-q { font-weight: 700; color: var(--text-dim); }
.qr-desig { font-family: var(--mono); font-weight: 600; }
.qr-given { color: var(--text-dim); } .qr-correct { font-weight: 600; } .qr-icon { text-align: center; }

/* ── Context menu ── */
.ctx-menu { display: none; position: fixed; z-index: 1300; min-width: 180px; background: #141a2e; border: 1px solid rgba(139,157,195,.3); border-radius: 8px; box-shadow: 0 12px 32px rgba(0,0,0,.5); padding: 4px; }
.ctx-menu .ctx-item { display: block; width: 100%; text-align: left; padding: 8px 12px; background: transparent; border: none; color: #e1e7f3; font-size: .84rem; font-weight: 500; border-radius: 5px; cursor: pointer; transition: background .12s; }
.ctx-menu .ctx-item:hover { background: var(--accent-lo); color: #fff; }

/* ── Modals ── */
.calc-modal { display: none; position: fixed; inset: 0; z-index: 1200; background: rgba(0,0,0,.72); backdrop-filter: blur(4px); align-items: flex-start; justify-content: center; padding: 24px 16px; overflow-y: auto; }
.calc-modal.active { display: flex; }
.calc-modal-box { background: #141a2e; border: 1px solid var(--border); border-radius: 12px; width: 100%; max-width: 760px; display: flex; flex-direction: column; box-shadow: 0 24px 64px rgba(0,0,0,.6); max-height: calc(100vh - 48px); overflow: hidden; }
.calc-modal-header { display: flex; align-items: center; justify-content: space-between; padding: 14px 20px; border-bottom: 1px solid var(--border); background: var(--surface2); flex-shrink: 0; }
.calc-modal-title { font-size: 1rem; font-weight: 800; color: var(--accent); }
.calc-modal-close { width: 34px; height: 34px; border: 1px solid var(--border); border-radius: 8px; background: var(--bg); color: var(--text-dim); font-size: 1.4rem; line-height: 1; padding: 0; display: flex; align-items: center; justify-content: center; cursor: pointer; transition: all .15s; }
.calc-modal-close:hover { border-color: var(--accent); color: var(--text); }
.calc-modal-body { padding: 16px 20px; overflow-y: auto; display: flex; flex-direction: column; gap: 12px; }
.calc-modal-body .cs-step { background: var(--bg); border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px; display: flex; flex-direction: column; gap: 6px; }
.cs-step-hd { display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.cs-num-pill { font-size: .64rem; font-weight: 800; text-transform: uppercase; letter-spacing: .06em; color: #f0c989; background: var(--accent-lo); padding: 2px 8px; border-radius: 20px; white-space: nowrap; }
.calc-modal-body .cs-title { font-size: .9rem; font-weight: 700; color: #e1e7f3; }
.cs-formula { font-family: "Cambria Math", "Times New Roman", serif; font-size: .92rem; color: #b6c3e0; background: var(--surface2); border-radius: 6px; padding: 8px 12px; border-left: 3px solid var(--accent); }
.cs-calc { font-family: var(--mono); font-size: .8rem; color: #e1e7f3; line-height: 1.7; }
.cs-result { font-size: .88rem; color: #b6c3e0; margin-top: 2px; }
.cs-result strong { font-family: var(--mono); font-size: .95rem; color: var(--green); }
.cm-field { display: flex; flex-direction: column; gap: 4px; }
.cm-field label { font-size: .8rem; color: var(--text-dim); font-weight: 600; }
.cm-rng { color: var(--accent); font-weight: 700; font-size: .72rem; }
.cm-field input { padding: 8px 10px; border: 1px solid var(--border); border-radius: 6px; background: var(--bg); color: var(--text); font-size: .88rem; font-family: var(--mono); }
.cm-field input:focus { outline: none; border-color: var(--accent); }
.cm-err { color: var(--red); font-size: .8rem; font-weight: 600; min-height: 1em; }
.cm-err:empty { display: none; }
.cm-actions { display: flex; gap: 10px; margin-top: 4px; }

/* ── Responsive ── */
@media (max-width: 920px) {
  .canvas-row { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .readout-grid { grid-template-columns: repeat(2, 1fr); }
  .slider-grid { grid-template-columns: 1fr 1fr; }
  .pp-field label { width: 90px; }
}
@media (max-width: 500px) {
  body { padding: 0 10px 50px; }
  .slider-grid { grid-template-columns: 1fr; }
  .readout-grid { grid-template-columns: 1fr 1fr; }
  .answer-grid { grid-template-columns: 1fr; }
  .q-designation { font-size: 1.15rem; }
  .bend-eq { left: 8px; max-width: 54%; padding: 6px 8px 8px; }
  .bend-eq .katex { font-size: .78em; }
  .angle-slider { right: 6px; padding: 7px 4px; }
  .as-rail { height: 150px; width: 26px; }
  .as-rail input[type="range"] { width: 150px; }
  .calc-modal { padding: 12px 8px; }
  .calc-modal-box { max-height: calc(100vh - 24px); }
  .ctrl-selects { gap: 8px; }
}