/* ==============================================================
   SYSTEM DESIGN ARCHITECTURE STUDIO — STYLES
   ============================================================== */

:root {
  --bg-dark: #0b0f19;
  --bg-panel: #111827;
  --bg-card: #1f293d;
  --border-color: #2b3648;
  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --accent-cyan: #38bdf8;
  --accent-purple: #c084fc;
  --accent-green: #34d399;
  --accent-amber: #fbbf24;
  --accent-red: #f87171;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: var(--font);
  background: var(--bg-dark);
  color: var(--text-main);
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

/* ---------- Header ---------- */
header {
  height: 54px;
  flex: 0 0 54px;
  background: var(--bg-panel);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 14px;
  gap: 12px;
  z-index: 30;
}
.logo-section { display: flex; align-items: center; gap: 12px; min-width: 0; }
.logo-badge {
  background: linear-gradient(135deg, var(--accent-purple), #60a5fa);
  color: #fff; font-weight: 700; padding: 4px 8px; border-radius: 6px;
  font-size: 11px; letter-spacing: 0.5px; white-space: nowrap;
}
.title-block { display: flex; flex-direction: column; min-width: 0; }
.app-title { font-size: 14px; font-weight: 700; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.app-tagline { font-size: 11px; color: var(--text-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 46vw; }
.toolbar { display: flex; align-items: center; gap: 6px; flex-shrink: 0; }
.template-select { width: 230px; height: 30px; font-size: 12px; }

/* ---------- Buttons ---------- */
.btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  font-family: var(--font);
  font-size: 12px; font-weight: 600;
  padding: 6px 10px; border-radius: 7px; cursor: pointer;
  transition: background .15s, border-color .15s, transform .05s;
  white-space: nowrap;
}
.btn:hover { background: #2a3752; border-color: #46536b; }
.btn:active { transform: scale(0.97); }
.btn-danger { border-color: #7f1d1d; color: #fca5a5; }
.btn-danger:hover { background: #450a0a; border-color: #b91c1c; }
.btn-mini { padding: 2px 8px; font-size: 11px; }

/* ---------- Flow bar ---------- */
.flow-bar {
  flex: 0 0 44px;
  background: #0d1322;
  border-bottom: 1px solid var(--border-color);
  display: flex; align-items: center; gap: 8px;
  padding: 0 14px;
  overflow-x: auto;
  z-index: 25;
}
.flow-bar::-webkit-scrollbar { height: 0; }
.chip-active {
  border-color: var(--chip);
  color: #fff;
  background: color-mix(in srgb, var(--chip) 16%, transparent);
  box-shadow: 0 0 10px color-mix(in srgb, var(--chip) 35%, transparent);
}
.flowbar-spacer { flex: 1; }
.player-btn { padding: 5px 9px; font-size: 12px; }
.play-btn { min-width: 74px; border-color: var(--accent-green); color: var(--accent-green); }
.play-btn:hover { background: rgba(52, 211, 153, 0.12); }

/* ---------- Layout ---------- */
.studio-container { flex: 1; display: flex; min-height: 0; }

/* ---------- Sidebar palette ---------- */

/* ---------- Canvas ---------- */

/* ---------- Nodes ---------- */

/* ---------- Edges ---------- */
text.edge-dim { opacity: 0.15; }

/* ---------- Connection banner ---------- */

/* ---------- Player card ---------- */

/* ---------- Zoom controls ---------- */

/* ---------- Inspector ---------- */
.insp-section-title {
  font-size: 10px; font-weight: 700; letter-spacing: 0.8px; text-transform: uppercase;
  color: var(--text-muted);
  margin: 16px 0 8px;
  padding-bottom: 5px;
  border-bottom: 1px solid var(--border-color);
  display: flex; justify-content: space-between; align-items: baseline;
}
.insp-section-title:first-child { margin-top: 0; }
.insp-hint { font-size: 9px; text-transform: none; letter-spacing: 0; font-weight: 500; }
.insp-empty { font-size: 12px; color: var(--text-muted); line-height: 1.7; }
.kbd-hints { font-size: 10.5px; color: #6b7280; }

.form-group { margin-bottom: 10px; }
.form-group label {
  display: block; font-size: 10.5px; font-weight: 600; color: var(--text-muted); margin-bottom: 4px;
}
.form-control {
  width: 100%;
  background: var(--bg-dark);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  font-family: var(--font); font-size: 12.5px;
  padding: 6px 8px; border-radius: 7px;
  outline: none;
}
.form-control:focus { border-color: var(--accent-cyan); }
.estimator-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }

.metric-card {
  background: var(--bg-dark);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 8px 10px;
  margin-bottom: 7px;
  display: flex; flex-direction: column; gap: 2px;
}
.metric-label { font-size: 10px; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.4px; }
.metric-value { font-size: 15px; font-weight: 700; color: var(--accent-cyan); }
.metric-green { color: var(--accent-green); }
.metric-subtext { font-size: 10.5px; color: var(--text-muted); }

/* ---------- Step list ---------- */
.step-list { max-height: 300px; overflow-y: auto; display: flex; flex-direction: column; gap: 5px; }
.step-row {
  display: flex; gap: 8px; align-items: flex-start;
  background: var(--bg-dark);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 7px 8px;
  cursor: pointer;
  transition: border-color .15s, opacity .15s;
}
.step-row:hover { border-color: #46536b; }
.step-row.step-done { opacity: 0.55; }
.step-row.step-current { border-color: var(--accent-cyan); background: #14203a; }
.step-num {
  --chip: #38bdf8;
  flex-shrink: 0;
  width: 20px; height: 20px; border-radius: 50%;
  background: color-mix(in srgb, var(--chip) 20%, transparent);
  color: var(--chip);
  font-size: 10.5px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.step-body { min-width: 0; }
.step-route { font-size: 10.5px; font-weight: 700; margin-bottom: 2px; line-height: 1.3; }
.step-desc { font-size: 10.5px; color: var(--text-muted); line-height: 1.45; }
.step-desc b { color: #cfd6e0; }

/* ---------- Modal ---------- */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(4, 7, 14, 0.75);
  backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center;
  z-index: 100;
}
.modal-content {
  width: 680px; max-width: 92vw; max-height: 84vh;
  overflow-y: auto;
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 20px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.6);
}
.modal-content h3 { font-size: 15px; margin-bottom: 12px; }
.modal-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.template-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 11px 12px;
  cursor: pointer;
  transition: border-color .15s, transform .1s;
  display: flex; align-items: flex-start; gap: 8px;
  margin-bottom: 8px;
}
.modal-grid .template-card { margin-bottom: 0; }
.template-card:hover { border-color: var(--accent-cyan); transform: translateY(-1px); }
.template-card-main { flex: 1; min-width: 0; }
.template-title { font-size: 13px; font-weight: 700; margin-bottom: 3px; }
.template-desc { font-size: 11px; color: var(--text-muted); line-height: 1.5; }
.template-meta { font-size: 10px; color: #6b7280; margin-top: 5px; }
.diff-badge {
  font-size: 9px; font-weight: 700; padding: 2px 6px; border-radius: 999px;
  vertical-align: middle; margin-left: 4px; text-transform: uppercase; letter-spacing: 0.4px;
}
.diff-easy { background: rgba(52, 211, 153, 0.15); color: var(--accent-green); }
.diff-medium { background: rgba(251, 191, 36, 0.15); color: var(--accent-amber); }
.diff-hard { background: rgba(248, 113, 113, 0.15); color: var(--accent-red); }

/* ---------- Toast ---------- */
.toast {
  position: fixed; bottom: 20px; left: 50%;
  transform: translate(-50%, 20px);
  background: var(--bg-card);
  border: 1px solid var(--accent-green);
  color: var(--text-main);
  font-size: 12.5px; font-weight: 600;
  padding: 9px 16px; border-radius: 9px;
  opacity: 0; pointer-events: none;
  transition: opacity .25s, transform .25s;
  z-index: 200;
}
.toast-show { opacity: 1; transform: translate(-50%, 0); }

/* ---------- Scrollbars ---------- */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #2b3648; border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #46536b; }

/* ---------- Architecture layers (swim lanes) ---------- */
.btn-primary { border-color: var(--accent-green); color: var(--accent-green); }
.btn-primary:hover { background: rgba(52, 211, 153, 0.12); }
.btn-on { border-color: var(--accent-cyan); color: var(--accent-cyan); background: rgba(56, 189, 248, 0.10); }

/* ---------- Practice problem card ---------- */
.practice-card {
  position: absolute; top: 14px; left: 14px;
  width: 380px; max-width: calc(100% - 140px);
  background: rgba(13, 19, 34, 0.95);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent-green);
  border-radius: 12px;
  padding: 11px 13px;
  z-index: 16;
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.5);
}
.pc-head { display: flex; justify-content: space-between; align-items: baseline; cursor: pointer; gap: 8px; }
.pc-title { font-size: 13px; font-weight: 700; }
.pc-collapse { color: var(--text-muted); font-size: 12px; }
.pc-brief { font-size: 12px; line-height: 1.55; color: #d6dbe4; margin-top: 7px; }
.pc-hints { margin: 8px 0 0 16px; font-size: 11.5px; color: var(--accent-amber); line-height: 1.6; }
.pc-btns { display: flex; gap: 5px; margin-top: 10px; flex-wrap: wrap; }
.btn-check { border-color: var(--accent-green); color: var(--accent-green); }
.btn-check:hover { background: rgba(52, 211, 153, 0.12); }

/* ---------- Practice catalog modal ---------- */
.modal-sub { font-size: 12px; color: var(--text-muted); line-height: 1.55; margin-bottom: 12px; }
.cat-title {
  font-size: 11px; font-weight: 700; letter-spacing: 0.8px; text-transform: uppercase;
  color: var(--accent-cyan); margin: 14px 0 7px;
  display: flex; align-items: center; gap: 7px;
}
.cat-count {
  background: var(--bg-card); color: var(--text-muted);
  font-size: 10px; padding: 1px 7px; border-radius: 999px;
}
.practice-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 5px; }
.practice-row {
  display: flex; justify-content: space-between; align-items: center; gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 8px 10px;
  cursor: pointer;
  transition: border-color .15s;
}
.practice-row:hover { border-color: var(--accent-green); }
.practice-title { font-size: 12px; font-weight: 600; min-width: 0; }
.practice-badges { display: flex; gap: 4px; align-items: center; flex-shrink: 0; }
.badge-attempted { font-size: 9px; font-weight: 700; color: var(--accent-cyan); background: rgba(56,189,248,0.12); padding: 2px 6px; border-radius: 999px; }
.badge-ref { font-size: 9px; font-weight: 700; color: var(--text-muted); background: rgba(148,163,184,0.15); padding: 2px 6px; border-radius: 999px; }

/* ---------- Self-check report ---------- */
.score-row { display: flex; align-items: baseline; gap: 12px; margin-bottom: 14px; }
.score-num { font-size: 34px; font-weight: 800; }
.score-grade { font-size: 13px; color: var(--text-main); font-weight: 600; }
.check-block { border: 1px solid var(--border-color); border-radius: 10px; padding: 10px 12px; margin-bottom: 9px; }
.check-block ul { margin: 4px 0 0 16px; }
.check-block li { font-size: 12px; line-height: 1.6; color: #cfd6e0; margin-bottom: 3px; }
.check-head { font-size: 12px; font-weight: 700; }
.check-bad { border-color: rgba(248, 113, 113, 0.45); background: rgba(248, 113, 113, 0.05); }
.check-warn { border-color: rgba(251, 191, 36, 0.4); background: rgba(251, 191, 36, 0.04); }
.check-good { border-color: rgba(52, 211, 153, 0.35); background: rgba(52, 211, 153, 0.04); }
.check-sug { border-color: rgba(56, 189, 248, 0.35); background: rgba(56, 189, 248, 0.04); }

/* ---------- Flow recorder ---------- */

/* ==============================================================
   LEARNING MODE — Revision / Patterns / Progress
   ============================================================== */
.mode-tabs { display: flex; gap: 4px; background: var(--bg-dark); padding: 3px; border-radius: 9px; border: 1px solid var(--border-color); }
.mode-tab {
  background: none; border: none; color: var(--text-muted);
  font-family: var(--font); font-size: 12.5px; font-weight: 600;
  padding: 6px 13px; border-radius: 7px; cursor: pointer; white-space: nowrap;
  transition: background .15s, color .15s;
}
.mode-tab:hover { color: var(--text-main); }
.mode-active { background: var(--bg-card); color: #fff; box-shadow: 0 1px 4px rgba(0,0,0,.35); }
.learn-hint { font-size: 11px; color: var(--text-muted); white-space: nowrap; }

.learn-root { flex: 1; display: flex; min-height: 0; }
.learn-nav {
  width: 268px; flex: 0 0 268px;
  background: var(--bg-panel); border-right: 1px solid var(--border-color);
  overflow-y: auto; padding: 14px 12px;
}
.learn-main { flex: 1; overflow-y: auto; padding: 26px 34px 80px; }

.nav-head { margin-bottom: 12px; }
.nav-title { font-size: 13px; font-weight: 700; margin-bottom: 6px; }
.nav-overall { display: flex; justify-content: space-between; font-size: 11px; color: var(--text-muted); margin-bottom: 5px; }
.nav-pct { color: var(--accent-green); font-weight: 700; }
.bar { height: 5px; background: var(--bg-dark); border-radius: 3px; overflow: hidden; }
.bar-fill { height: 100%; background: linear-gradient(90deg, var(--accent-cyan), var(--accent-green)); transition: width .3s; }
.nav-search { margin-bottom: 10px; }
.nav-cat {
  display: flex; justify-content: space-between; align-items: center; gap: 6px;
  padding: 7px 9px; border-radius: 7px; cursor: pointer;
  font-size: 12px; color: var(--text-muted);
  transition: background .12s, color .12s;
}
.nav-cat:hover { background: var(--bg-card); color: var(--text-main); }
.nav-cat-active { background: var(--bg-card); color: #fff; font-weight: 600; box-shadow: inset 2px 0 0 var(--accent-cyan); }
.nav-cat-n { font-size: 10px; color: var(--text-muted); background: var(--bg-dark); padding: 1px 7px; border-radius: 999px; flex-shrink: 0; }
.nav-note { font-size: 11px; color: var(--text-muted); line-height: 1.6; margin: 10px 2px; }

.learn-intro { margin-bottom: 22px; max-width: 860px; }
.learn-intro h2 { font-size: 21px; font-weight: 700; margin-bottom: 7px; }
.learn-intro p { font-size: 13px; color: var(--text-muted); line-height: 1.65; }

.concept-group { margin-bottom: 28px; }
.group-title {
  font-size: 11px; font-weight: 700; letter-spacing: 0.9px; text-transform: uppercase;
  color: var(--accent-cyan); margin-bottom: 11px;
  padding-bottom: 6px; border-bottom: 1px solid var(--border-color);
}
.concept-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(310px, 1fr)); gap: 10px; }
.concept-card {
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 10px; padding: 12px 13px; cursor: pointer;
  transition: border-color .15s, transform .1s;
  display: flex; flex-direction: column; gap: 7px;
}
.concept-card:hover { border-color: var(--accent-cyan); transform: translateY(-1px); }
.cc-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 8px; }
.cc-title { font-size: 13px; font-weight: 700; line-height: 1.35; }
.cc-mastery { font-size: 14px; font-weight: 700; flex-shrink: 0; }
.cc-one { font-size: 11.5px; color: var(--text-muted); line-height: 1.55; }
.cc-one b { color: #cfd6e0; }
.cc-foot { display: flex; gap: 5px; flex-wrap: wrap; margin-top: auto; }
.cc-tag { font-size: 9.5px; font-weight: 600; color: var(--text-muted); background: var(--bg-dark); padding: 2px 7px; border-radius: 999px; }
.cc-pattern { color: var(--accent-purple); background: rgba(192,132,252,0.13); }

/* ---------- concept page ---------- */
.cp { max-width: 880px; }
.cp-back { font-size: 12px; color: var(--text-muted); cursor: pointer; margin-bottom: 16px; display: inline-block; }
.cp-back:hover { color: var(--accent-cyan); }
.cp-header { margin-bottom: 16px; }
.cp-header h1 { font-size: 26px; font-weight: 700; line-height: 1.25; margin-bottom: 10px; }
.cp-one {
  font-size: 15px; line-height: 1.6; color: #dfe4ec;
  padding: 12px 15px; background: var(--bg-panel);
  border-left: 3px solid var(--accent-cyan); border-radius: 0 9px 9px 0;
}
.cp-one b { color: #fff; }

.cp-mastery { display: flex; align-items: center; gap: 6px; flex-wrap: wrap; margin: 16px 0 24px; }
.cp-mastery-label { font-size: 11px; color: var(--text-muted); font-weight: 600; margin-right: 4px; }
.mastery-btn {
  --mc: #6b7280;
  background: none; border: 1px solid var(--border-color); color: var(--text-muted);
  font-family: var(--font); font-size: 11.5px; font-weight: 600;
  padding: 5px 11px; border-radius: 999px; cursor: pointer; transition: all .15s;
}
.mastery-btn:hover { border-color: var(--mc); color: var(--mc); }
.mastery-on { border-color: var(--mc); color: var(--mc); background: color-mix(in srgb, var(--mc) 14%, transparent); }

.cp-sec { margin-bottom: 22px; }
.cp-sec h3 {
  font-size: 11px; font-weight: 700; letter-spacing: 0.9px; text-transform: uppercase;
  color: var(--text-muted); margin-bottom: 9px;
  display: flex; align-items: baseline; gap: 8px;
}
.cp-hint { font-size: 10px; font-weight: 500; text-transform: none; letter-spacing: 0; color: #6b7280; }
.cp-sec p { font-size: 13.5px; line-height: 1.75; color: #d6dbe4; }
.cp-sec p b, .cp-sec li b { color: #fff; }
.cp-sec ul { margin-left: 17px; }
.cp-sec li { font-size: 13px; line-height: 1.7; color: #d6dbe4; margin-bottom: 4px; }
.cp-two { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 900px) { .cp-two { grid-template-columns: 1fr; } }
.cp-use, .cp-avoid, .cp-good, .cp-bad, .cp-example {
  background: var(--bg-panel); border: 1px solid var(--border-color);
  border-radius: 10px; padding: 13px 15px;
}
.cp-use { border-left: 3px solid var(--accent-green); }
.cp-avoid { border-left: 3px solid var(--accent-red); }
.cp-good { border-left: 3px solid var(--accent-green); }
.cp-bad { border-left: 3px solid var(--accent-amber); }
.cp-example { border-left: 3px solid var(--accent-purple); }

.cp-flow {
  display: flex; align-items: center; gap: 7px; flex-wrap: wrap;
  margin-top: 13px; padding: 13px; background: var(--bg-dark);
  border: 1px solid var(--border-color); border-radius: 9px;
}
.flow-step {
  background: var(--bg-card); border: 1px solid var(--border-color);
  padding: 6px 11px; border-radius: 7px; font-size: 11.5px; font-weight: 600; color: #dfe4ec;
}
.flow-arrow { color: var(--accent-cyan); font-size: 13px; font-weight: 700; }

.qa { margin-bottom: 8px; border: 1px solid var(--border-color); border-radius: 9px; overflow: hidden; background: var(--bg-panel); }
.qa-q {
  display: flex; gap: 9px; align-items: flex-start;
  padding: 11px 13px; cursor: pointer; font-size: 13px; font-weight: 600; line-height: 1.55;
  transition: background .12s;
}
.qa-q:hover { background: var(--bg-card); }
.qa-mark {
  flex-shrink: 0; width: 19px; height: 19px; border-radius: 5px;
  background: rgba(56,189,248,0.15); color: var(--accent-cyan);
  font-size: 10px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.qa-mark-a { background: rgba(52,211,153,0.15); color: var(--accent-green); }
.qa-toggle { margin-left: auto; font-size: 10px; color: var(--text-muted); font-weight: 600; flex-shrink: 0; }
.qa-a {
  display: flex; gap: 9px; align-items: flex-start;
  padding: 0 13px 13px 13px; font-size: 12.5px; line-height: 1.7; color: #cfd6e0;
}
.qa-a b { color: #fff; }

.chip-row { display: flex; gap: 6px; flex-wrap: wrap; }
.chip {
  background: var(--bg-card); border: 1px solid var(--border-color);
  padding: 5px 11px; border-radius: 999px; font-size: 11.5px; font-weight: 600;
  cursor: pointer; transition: all .15s; color: var(--text-muted);
}
.chip:hover { border-color: var(--accent-cyan); color: #fff; }
.chip-problem:hover { border-color: var(--accent-green); }

/* ---------- patterns extras ---------- */
.pattern-problems { display: flex; flex-direction: column; gap: 6px; }
.pp-row {
  display: flex; align-items: center; gap: 12px;
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 9px; padding: 10px 13px; cursor: pointer; transition: border-color .15s;
}
.pp-row:hover { border-color: var(--accent-green); }
.pp-title { font-size: 12.5px; font-weight: 700; min-width: 190px; }
.pp-pats { display: flex; gap: 4px; flex-wrap: wrap; }

/* ---------- progress ---------- */
.prog-row {
  display: flex; align-items: center; gap: 12px;
  padding: 9px 11px; border-radius: 9px; cursor: pointer;
  background: var(--bg-card); border: 1px solid var(--border-color); margin-bottom: 6px;
  transition: border-color .15s;
}
.prog-row:hover { border-color: var(--accent-cyan); }
.prog-name { font-size: 12.5px; font-weight: 600; width: 240px; flex-shrink: 0; }
.prog-bar { flex: 1; height: 7px; background: var(--bg-dark); border-radius: 4px; overflow: hidden; }
.prog-fill { height: 100%; border-radius: 4px; transition: width .3s; }
.prog-pct { font-size: 12px; font-weight: 700; width: 40px; text-align: right; }
.prog-n { font-size: 10px; color: var(--text-muted); width: 26px; text-align: right; }

/* ---------- Section-0+ learning fields (optional per concept) ---------- */
.cp-simple {
  background: var(--bg-panel); border: 1px solid var(--border-color);
  border-left: 3px solid #2dd4bf; border-radius: 10px; padding: 13px 15px;
}
.cp-mistakes {
  background: var(--bg-panel); border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent-amber); border-radius: 10px; padding: 13px 15px;
}
.cp-sayit {
  background: rgba(56, 189, 248, 0.05); border: 1px solid rgba(56, 189, 248, 0.25);
  border-radius: 10px; padding: 13px 15px;
}
.cp-sayit p { font-style: italic; color: #e5eaf2; }
.part {
  background: var(--bg-panel); border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent-purple);
  border-radius: 9px; padding: 11px 14px; margin-bottom: 8px;
}
.part-name { font-size: 12.5px; font-weight: 700; color: #fff; margin-bottom: 4px; }
.part-text { font-size: 13px; line-height: 1.7; color: #d6dbe4; }
.part-text b { color: #fff; }

/* ---------- Interview Loop: whiteboard ---------- */
/* body is a flex column: header, #flow-bar, #studio-root, #learn-root — order puts the drawer bar under the canvas */
#studio-root { order: 2; }
#flow-bar { order: 3; }
#learn-root { order: 2; }
.drawer-bar { align-items: center; gap: 6px; padding: 6px 12px; }
.bar-hidden { display: none !important; }
.drawer-btn { font-size: 12px; }
.bar-hint { font-size: 11px; color: var(--text-muted); font-family: ui-monospace, Menlo, monospace; }
.save-status { font-size: 11px; color: var(--text-muted); margin-right: 8px; }

/* left panel */
.side { width: 264px; flex-shrink: 0; background: var(--bg-panel); border-right: 1px solid var(--border-color); display: flex; flex-direction: column; min-height: 0; overflow-y: auto; }
.side-section { padding: 10px 12px; border-bottom: 1px solid var(--border-color); }
.side-section:last-child { border-bottom: none; }
.side-grow { flex: 1; }
.side-foot { display: flex; gap: 4px; flex-wrap: wrap; }
.side-new { width: 100%; }
.side-back { width: 100%; text-align: left; }
.side-current { font-size: 13px; font-weight: 700; margin-top: 8px; line-height: 1.35; }
.side-title { font-size: 10.5px; font-weight: 700; letter-spacing: .6px; text-transform: uppercase; color: var(--text-muted); margin-bottom: 6px; display: flex; align-items: center; gap: 6px; }
.side-count { font-size: 10px; color: var(--text-muted); font-weight: 500; }
.side-empty { font-size: 12px; color: var(--text-muted); padding: 4px 0; }
.side-hint { font-size: 11px; color: var(--text-muted); line-height: 1.5; margin-top: 8px; }
.side-hint b { color: var(--accent-cyan); font-family: ui-monospace, monospace; }
.side-row { display: flex; align-items: center; gap: 6px; padding: 6px 8px; border-radius: 7px; cursor: pointer; font-size: 12.5px; line-height: 1.3; }
.side-row:hover { background: var(--bg-card); }
.side-row-title { flex: 1; min-width: 0; }
.side-row-badges { display: flex; gap: 4px; align-items: center; flex-shrink: 0; }
.side-x { background: none; border: none; color: var(--text-muted); cursor: pointer; font-size: 11px; padding: 0 3px; }
.side-x:hover { color: var(--accent-red); }
.side-cat { margin-top: 4px; }
.side-cat summary { cursor: pointer; font-size: 12px; font-weight: 600; padding: 5px 4px; color: #d6dbe4; list-style: none; display: flex; align-items: center; gap: 6px; }
.side-cat summary::before { content: '▸'; color: var(--text-muted); font-size: 10px; }
.side-cat[open] summary::before { content: '▾'; }
.side-cat .side-row { padding-left: 18px; }

.comp-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 5px; margin-top: 8px; }
.comp-item { display: flex; align-items: center; gap: 6px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 8px; padding: 7px 8px; font-size: 11.5px; cursor: grab; user-select: none; line-height: 1.2; }
.comp-item:hover { border-color: var(--accent-cyan); }
.comp-item:active { cursor: grabbing; }
.comp-dot { width: 9px; height: 9px; border-radius: 50%; flex-shrink: 0; }
.comp-label { min-width: 0; }

/* canvas */
.canvas-view { flex: 1; display: flex; min-height: 0; min-width: 0; }
.canvas-area { flex: 1; min-width: 0; position: relative; display: flex; min-height: 0; }
.excalidraw-host { flex: 1; min-width: 0; height: 100%; position: relative; background: #121212; }
.excalidraw-host .excalidraw { --color-primary: #38bdf8; }
.canvas-empty { position: absolute; inset: 0; z-index: 3; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; pointer-events: none; padding: 40px; }
.canvas-empty-title { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.canvas-empty-sub { font-size: 13px; color: var(--text-muted); line-height: 1.6; max-width: 520px; }
.canvas-empty-sub b { color: var(--accent-cyan); font-family: ui-monospace, monospace; }

/* Strip Excalidraw's chrome down to: select · box · arrow · text, plus zoom + undo/redo */
.excalidraw .main-menu-trigger, .excalidraw .sidebar-trigger, .excalidraw .HintViewer, .excalidraw .help-icon,
.excalidraw .App-toolbar__extra-tools-trigger, .excalidraw .App-toolbar__divider,
.excalidraw .App-toolbar label:has([data-testid="toolbar-lock"]), .excalidraw .App-toolbar label:has([data-testid="toolbar-hand"]),
.excalidraw .App-toolbar label:has([data-testid="toolbar-diamond"]), .excalidraw .App-toolbar label:has([data-testid="toolbar-ellipse"]),
.excalidraw .App-toolbar label:has([data-testid="toolbar-line"]), .excalidraw .App-toolbar label:has([data-testid="toolbar-freedraw"]),
.excalidraw .App-toolbar label:has([data-testid="toolbar-image"]), .excalidraw .App-toolbar label:has([data-testid="toolbar-eraser"]),
.excalidraw .App-toolbar label:has([data-testid="toolbar-frame"]), .excalidraw .App-toolbar label:has([data-testid="toolbar-laser"]),
.excalidraw .App-toolbar [data-testid="dropdown-menu-button"], .excalidraw .App-toolbar .dropdown-menu-button,
.excalidraw .welcome-screen-center, .excalidraw .welcome-screen-decor { display: none !important; }
.excalidraw .App-toolbar, .excalidraw .App-toolbar-container, .excalidraw .FixedSideContainer.FixedSideContainer_side_top { display: none !important; }

/* notes drawer */
.drawer { width: 360px; flex-shrink: 0; background: var(--bg-panel); border-left: 1px solid var(--border-color); display: flex; flex-direction: column; min-height: 0; }
.drawer-head { display: flex; align-items: center; justify-content: space-between; padding: 10px 12px; border-bottom: 1px solid var(--border-color); }
.drawer-title { font-size: 13px; font-weight: 700; }
.drawer-body { flex: 1; overflow-y: auto; padding: 12px; }
.phase-guide { font-size: 12px; color: var(--text-muted); line-height: 1.6; margin: 6px 0 10px; }
.notes-area { width: 100%; min-height: 220px; resize: vertical; background: var(--bg-dark); color: var(--text-main); border: 1px solid var(--border-color); border-radius: 8px; padding: 10px; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 12.5px; line-height: 1.55; outline: none; }
.notes-area:focus { border-color: var(--accent-cyan); }
.notes-short { min-height: 96px; }
.notes-tiny { min-height: 56px; }
.pc-brief-block { margin-bottom: 12px; }
.pc-details { margin-top: 8px; }
.pc-details summary { cursor: pointer; font-size: 12px; color: var(--accent-amber); }
.insp-btn-row { display: flex; gap: 6px; flex-wrap: wrap; }
.entry { border: 1px solid var(--border-color); border-radius: 10px; padding: 8px; margin-bottom: 8px; display: flex; flex-direction: column; gap: 6px; }
.entry-row { display: flex; gap: 6px; align-items: flex-end; }
.entry-row .form-group { flex: 1; margin-bottom: 0; }
.entry-row .form-control { flex: 1; }
.entry-method { flex: 0 0 90px !important; }
.estimator { display: block; }

/* reference viewer */
.ref-overlay { position: fixed; inset: 0; z-index: 900; background: var(--bg-dark); display: flex; flex-direction: column; }
.ref-head { display: flex; align-items: center; gap: 10px; padding: 8px 14px; border-bottom: 1px solid var(--border-color); background: var(--bg-panel); }
.ref-title { font-size: 15px; font-weight: 700; }
.ref-tagline { font-size: 12px; color: var(--text-muted); }
.ref-body { flex: 1; display: flex; min-height: 0; }
.ref-side { width: 380px; flex-shrink: 0; border-left: 1px solid var(--border-color); background: var(--bg-panel); overflow-y: auto; padding: 12px; }
.ref-flow { margin-bottom: 14px; }
.ref-flow-name { font-size: 12.5px; font-weight: 700; margin-bottom: 6px; }
.ref-side .step-row { cursor: default; }

/* ---------- practice pad: list + design screens ---------- */
.list-view { flex: 1; display: flex; min-height: 0; }
.list-wrap { max-width: 860px; margin: 0 auto; padding: 0 24px; }
.list-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin: 18px 0 8px; }
.list-head h2 { font-size: 16px; font-weight: 700; }
.list-count { font-size: 11px; color: var(--text-muted); }
.list-block { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.list-row { display: flex; align-items: center; gap: 8px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 9px; padding: 10px 12px; cursor: pointer; }
.list-row:hover { border-color: var(--accent-cyan); }
.list-row-title { flex: 1; min-width: 0; font-size: 13px; font-weight: 600; }
.list-row-sub { font-size: 11px; color: var(--text-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 55%; }
.list-row-badges { display: flex; gap: 4px; align-items: center; flex-shrink: 0; }
.list-x { background: none; border: none; color: var(--text-muted); cursor: pointer; font-size: 12px; padding: 0 4px; }
.list-x:hover { color: var(--accent-red); }
.list-empty { font-size: 12.5px; color: var(--text-muted); padding: 10px 2px; grid-column: 1 / -1; }
.list-cat { margin-top: 6px; }
.list-cat summary { cursor: pointer; font-size: 13px; font-weight: 600; padding: 6px 2px; color: #d6dbe4; list-style: none; display: flex; align-items: center; gap: 6px; }
.list-cat summary::before { content: '▸'; color: var(--text-muted); font-size: 11px; }
.list-cat[open] summary::before { content: '▾'; }
.list-cat .list-block { margin: 4px 0 8px; }

.design-view { flex: 1; display: flex; min-height: 0; min-width: 0; }
.side-brief { font-size: 12.5px; line-height: 1.55; color: #d6dbe4; margin-top: 10px; }
.side-hints { margin-top: 8px; }
.side-hints summary { cursor: pointer; font-size: 12px; color: var(--accent-amber); }
.side-hints ul { margin: 6px 0 0 16px; font-size: 11.5px; color: var(--accent-amber); line-height: 1.55; }
.side-actions { display: flex; gap: 4px; flex-wrap: wrap; margin-top: 10px; }
.comp-grid-top { margin-bottom: 6px; }
.comp-custom { border-style: dashed; }
.comp-tool { justify-content: center; font-weight: 600; color: var(--accent-cyan); }

/* ---------- sidebar: layers + components with icons ---------- */
.layer-list { display: flex; flex-direction: column; gap: 4px; }
.layer-item { display: flex; align-items: center; gap: 8px; padding: 6px 8px; border-radius: 8px; border: 1px solid var(--border-color); border-left: 4px solid var(--lc); background: var(--bg-card); cursor: grab; user-select: none; font-size: 12px; }
.layer-item:hover { border-color: var(--lc); }
.layer-num { font-weight: 800; color: var(--lc); font-size: 12px; width: 12px; }
.layer-name { font-weight: 600; letter-spacing: .3px; font-size: 11.5px; }
.comp-tools { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 4px; margin: 8px 0 4px; }
.comp-group { margin-top: 8px; }
.comp-group-title { font-size: 10px; font-weight: 800; letter-spacing: .6px; text-transform: uppercase; margin: 6px 0 3px; }
.comp-row { display: flex; align-items: center; gap: 8px; padding: 5px 8px; border-radius: 7px; border: 1px solid transparent; cursor: grab; user-select: none; font-size: 12.5px; }
.comp-row:hover { background: var(--bg-card); border-color: var(--border-color); }
.comp-row:active { cursor: grabbing; }
.comp-row svg { flex-shrink: 0; }
.comp-row.tool { justify-content: center; background: var(--bg-card); border-color: var(--border-color); cursor: pointer; font-weight: 600; font-size: 12px; }
.tool-glyph { color: var(--accent-cyan); font-weight: 800; }
.excalidraw-host { background: #ffffff; }

/* ---------- systems list as cards ---------- */
.list-wrap { max-width: 1180px; }
.list-sub { font-size: 12px; color: var(--text-muted); margin-top: 2px; }
.list-cat-title { font-size: 11px; font-weight: 800; letter-spacing: .6px; text-transform: uppercase; color: var(--accent-cyan); margin: 18px 0 8px; }
.sys-card { cursor: pointer; }
.sys-desc { display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; margin: 6px 0 10px; }
.cc-saved { color: var(--accent-green); background: rgba(52,211,153,0.12); }
.cc-ref { color: var(--accent-amber); background: rgba(251,191,36,0.12); }
.cc-easy { color: var(--accent-green); } .cc-medium { color: var(--accent-amber); } .cc-hard { color: var(--accent-red); }

.edit-box { background: rgba(56,189,248,0.06); border-top: 1px solid var(--accent-cyan); border-bottom: 1px solid var(--accent-cyan); }
.edit-box .form-group { margin-bottom: 8px; }

.todo-side { width: 264px; flex-shrink: 0; background: var(--bg-panel); border-right: 1px solid var(--border-color); overflow-y: auto; padding: 12px; }
.todo-row { display: flex; align-items: center; gap: 8px; padding: 6px 8px; border-radius: 7px; cursor: pointer; font-size: 12.5px; line-height: 1.3; }
.todo-row:hover { background: var(--bg-card); }
.todo-check { color: var(--text-muted); width: 12px; flex-shrink: 0; }
.todo-done { color: var(--text-muted); }
.todo-done .todo-check { color: var(--accent-green); }
.list-view .list-wrap { flex: 1; overflow-y: auto; padding: 22px 28px; max-width: none; margin: 0; }