/* ===== Smith Chart Studio ===== */
:root {
  --bg: #0f141b;
  --panel: #161d27;
  --panel-2: #1c2531;
  --border: #273245;
  --text: #e8edf4;
  --muted: #93a0b4;
  --accent: #e4573d;
  --accent-soft: rgba(228, 87, 61, 0.14);
  --good: #2fae72;
  --bad: #e05555;
  --blue: #4a90d9;
  --mono: "Cascadia Mono", Consolas, "Courier New", monospace;
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
}

body {
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", system-ui, sans-serif;
  font-size: 14px;
  overflow: hidden;
}

h1, h2 { margin: 0; font-weight: 600; }

/* ---------- top bar ---------- */
.topbar {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 8px 18px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  flex: 0 0 auto;
}

.brand { display: flex; align-items: center; gap: 12px; }
.brand h1 { font-size: 17px; letter-spacing: 0.2px; }
.brand .tagline { font-size: 11.5px; color: var(--muted); }
.brand .tagline b { color: var(--accent); font-weight: 600; }

.tabs { display: flex; gap: 6px; margin-left: 12px; }

.tab-btn {
  padding: 8px 18px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}
.tab-btn:hover { color: var(--text); background: var(--panel-2); }
.tab-btn.active {
  color: var(--text);
  background: var(--accent-soft);
  border-color: var(--accent);
}

.top-actions { margin-left: auto; }

.ghost-btn {
  padding: 7px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 12.5px;
}
.ghost-btn:hover { color: var(--text); border-color: var(--muted); }

/* ---------- layout ---------- */
main { flex: 1 1 auto; min-height: 0; }

.tab-panel {
  display: none;
  height: 100%;
}
.tab-panel.active { display: flex; }

.chart-wrap {
  flex: 1 1 auto;
  min-width: 0;
  position: relative;
  display: flex;
  align-items: stretch;
  justify-content: center;
  padding: 8px;
}

.chart-wrap canvas {
  width: 100%;
  height: 100%;
  display: block;
  border-radius: 12px;
  outline: none;
  cursor: crosshair;
}

.chart-note {
  position: absolute;
  left: 18px;
  bottom: 14px;
  font-size: 11px;
  color: var(--muted);
  background: rgba(15, 20, 27, 0.75);
  padding: 4px 10px;
  border-radius: 6px;
  pointer-events: none;
  max-width: 60%;
}

/* ---------- sidebar ---------- */
.sidebar {
  flex: 0 0 370px;
  overflow-y: auto;
  padding: 10px 12px 20px 4px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
}

.card h2 {
  font-size: 12.5px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--muted);
  margin-bottom: 10px;
}

details.card summary {
  cursor: pointer;
  font-size: 12.5px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--muted);
  user-select: none;
}

.field-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px 10px;
}

.field-grid label, .preset-row {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 12px;
  color: var(--muted);
}

.preset-row { margin-bottom: 8px; }

input[type="number"], select {
  width: 100%;
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--panel-2);
  color: var(--text);
  font-family: var(--mono);
  font-size: 13px;
}
input[type="number"]:focus, select:focus {
  border-color: var(--accent);
  outline: none;
}

.joined { display: flex; gap: 6px; }
.joined input { flex: 1 1 auto; min-width: 0; }
.joined select { flex: 0 0 74px; }

.hint { font-size: 11.5px; color: var(--muted); margin: 8px 0 0; line-height: 1.5; }

/* readouts */
.readouts {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 14px;
  margin: 0;
  font-size: 13px;
}
.readouts dt { color: var(--muted); }
.readouts dd {
  margin: 0;
  font-family: var(--mono);
  text-align: right;
  white-space: nowrap;
}
.readouts dd.em { color: var(--accent); font-weight: 600; }

.radio-row { display: flex; gap: 16px; font-size: 12.5px; color: var(--muted); margin-bottom: 8px; }
.radio-row label { display: flex; align-items: center; gap: 5px; }

.slider-row { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.slider-row input[type="range"] { flex: 1 1 auto; accent-color: var(--accent); }
.narrow { width: 78px !important; flex: 0 0 78px; }
.unit { color: var(--muted); }

.check-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 7px 10px;
  font-size: 12.5px;
  color: var(--muted);
}
.check-grid label { display: flex; align-items: center; gap: 6px; cursor: pointer; }
.check-grid input { accent-color: var(--accent); }

.btn-row { display: flex; gap: 8px; margin-top: 10px; flex-wrap: wrap; }

.small-btn {
  padding: 7px 13px;
  border: 1px solid var(--accent);
  border-radius: 7px;
  background: var(--accent-soft);
  color: var(--text);
  font-size: 12.5px;
  font-weight: 600;
  cursor: pointer;
}
.small-btn:hover { background: var(--accent); }
.small-btn.ghost {
  border-color: var(--border);
  background: transparent;
  color: var(--muted);
}
.small-btn.ghost:hover { color: var(--text); border-color: var(--muted); background: var(--panel-2); }
.small-btn:disabled { opacity: 0.45; cursor: default; }

.ref-list {
  margin: 10px 0 0;
  padding-left: 18px;
  font-size: 12.5px;
  color: var(--muted);
  line-height: 1.9;
}

/* ---------- matching lab ---------- */
.el-list { display: flex; flex-direction: column; gap: 8px; margin-bottom: 10px; }

.el-card {
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  background: var(--panel-2);
  padding: 8px 10px;
}

.el-head {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 6px;
  font-size: 12.5px;
  font-weight: 600;
}
.el-head .el-title { flex: 1 1 auto; }
.el-head button {
  border: none;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
  padding: 2px 5px;
  border-radius: 4px;
}
.el-head button:hover { color: var(--text); background: var(--border); }

.el-fields { display: flex; gap: 8px; align-items: end; }
.el-fields label {
  display: flex;
  flex-direction: column;
  gap: 3px;
  font-size: 11px;
  color: var(--muted);
  flex: 1;
}
.el-note { font-size: 11px; color: var(--muted); margin-top: 6px; font-family: var(--mono); }

.add-row { display: flex; gap: 8px; }
.add-row select { flex: 1 1 auto; }

.auto-out { margin-top: 10px; display: flex; flex-direction: column; gap: 8px; }
.auto-sol {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 10px;
  background: var(--panel-2);
  font-size: 12.5px;
}
.auto-sol .sol-name { color: var(--muted); font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; }
.auto-sol .sol-parts { font-family: var(--mono); margin: 4px 0 6px; }

.verdict {
  font-size: 13px;
  font-weight: 600;
  padding: 8px 10px;
  border-radius: 7px;
  margin-bottom: 10px;
  background: var(--panel-2);
  border: 1px solid var(--border);
}
.verdict.good { color: var(--good); border-color: var(--good); }
.verdict.warn { color: #e0a53d; }

.stages { margin-top: 10px; font-size: 12px; color: var(--muted); font-family: var(--mono); line-height: 1.8; }
.stages .dot { display: inline-block; width: 9px; height: 9px; border-radius: 50%; margin-right: 7px; }

/* ---------- learn tab ---------- */
.lesson-nav {
  flex: 0 0 225px;
  padding: 14px 10px 14px 14px;
  overflow-y: auto;
  border-right: 1px solid var(--border);
  background: var(--panel);
}
.lesson-nav h2 {
  font-size: 12.5px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--muted);
  margin-bottom: 10px;
}
.lesson-nav ul { list-style: none; margin: 0 0 12px; padding: 0; display: flex; flex-direction: column; gap: 4px; }
.lesson-nav li {
  padding: 8px 10px;
  border-radius: 7px;
  font-size: 12.5px;
  cursor: pointer;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 8px;
  border: 1px solid transparent;
}
.lesson-nav li:hover { background: var(--panel-2); color: var(--text); }
.lesson-nav li.active { background: var(--accent-soft); border-color: var(--accent); color: var(--text); }
.lesson-nav li .tick { color: var(--good); font-weight: 700; visibility: hidden; }
.lesson-nav li.done .tick { visibility: visible; }
.lesson-nav li .num { color: var(--muted); font-size: 11px; }

.lesson-panel { flex-basis: 390px; }

.lesson-head { padding: 10px 14px; }
.lesson-head .l-title { font-size: 15px; font-weight: 600; }
.lesson-head .l-step { font-size: 11.5px; color: var(--muted); margin-top: 2px; }

.lesson-body-card { flex: 0 0 auto; }
.lesson-body { font-size: 13.5px; line-height: 1.65; }
.lesson-body p { margin: 0 0 10px; }
.lesson-body b, .lesson-body strong { color: var(--accent); }
.lesson-body code {
  font-family: var(--mono);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 5px;
  font-size: 12.5px;
}
.lesson-body ul { margin: 6px 0 10px; padding-left: 20px; }
.lesson-body li { margin-bottom: 4px; }

.task-box {
  border: 1px dashed var(--accent);
  border-radius: 8px;
  background: var(--accent-soft);
  padding: 10px 12px;
  font-size: 13px;
  margin-top: 6px;
}
.task-box .task-label {
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--accent);
}

.quiz-opts { display: flex; flex-direction: column; gap: 6px; margin-top: 8px; }
.quiz-opts button {
  text-align: left;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: var(--panel-2);
  color: var(--text);
  font-size: 13px;
  cursor: pointer;
  font-family: var(--mono);
}
.quiz-opts button:hover { border-color: var(--accent); }
.quiz-opts button.correct { border-color: var(--good); color: var(--good); }
.quiz-opts button.wrong { border-color: var(--bad); color: var(--bad); }

.feedback { margin-top: 10px; font-size: 13px; min-height: 20px; line-height: 1.5; }
.feedback.ok { color: var(--good); }
.feedback.no { color: var(--bad); }

.progress-dots { display: flex; gap: 6px; padding: 4px 6px; flex-wrap: wrap; }
.progress-dots span {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: var(--border);
}
.progress-dots span.done { background: var(--good); }
.progress-dots span.cur { background: var(--accent); }

/* ---------- status bar ---------- */
.statusbar {
  flex: 0 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 6px 18px;
  background: var(--panel);
  border-top: 1px solid var(--border);
  font-size: 12px;
  color: var(--muted);
  font-family: var(--mono);
}
.status-right { font-family: "Segoe UI", system-ui, sans-serif; }

/* scrollbars */
::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: var(--muted); }

/* ============================================================
   MOBILE / NARROW  (≤ 900px)
   Desktop uses a fixed-height, non-scrolling split view, but the
   370px control panel starves the chart on anything narrow. Below
   this width we let the whole page scroll and stack everything:
   a big chart on top, controls below.
   ============================================================ */
@media (max-width: 900px) {
  html, body { height: auto; overflow: visible; }
  body { overflow-x: hidden; }

  /* top bar wraps instead of overflowing */
  .topbar {
    position: sticky; top: 0; z-index: 20;
    gap: 10px 14px;
    flex-wrap: wrap;
    padding: 8px 12px;
  }
  .brand h1 { font-size: 15px; }
  .brand .tagline { display: none; }
  .tabs { margin-left: 0; order: 3; width: 100%; }
  .tab-btn { flex: 1 1 0; padding: 9px 10px; text-align: center; }
  .top-actions { margin-left: auto; }
  #homeLink { display: none; }   /* browser back covers this on mobile; keeps the header to two rows */
  .top-actions .ghost-btn { padding: 6px 10px; }

  main { flex: 0 0 auto; min-height: 0; }

  /* ---- Explore: chart over sidebar ---- */
  .tab-panel.active { flex-direction: column; height: auto; }

  .chart-wrap {
    flex: 0 0 auto;
    height: min(92vw, 520px);
    padding: 6px;
  }
  .chart-wrap canvas { touch-action: none; }   /* drag the point without scrolling the page */
  .chart-note {
    left: 10px; bottom: 10px;
    max-width: calc(100% - 20px);
    font-size: 10px;
  }

  .sidebar {
    flex: 0 0 auto;
    width: 100%;
    overflow: visible;
    padding: 10px 12px 22px;
  }

  /* ---- Learn: nav over chart over lesson ---- */
  .lesson-nav {
    flex: 0 0 auto;
    width: 100%;
    border-right: 0;
    border-bottom: 1px solid var(--border);
    padding: 12px;
  }
  .lesson-nav ul {
    flex-direction: row;
    flex-wrap: nowrap;
    overflow-x: auto;
    gap: 6px;
    padding-bottom: 4px;
    -webkit-overflow-scrolling: touch;
  }
  .lesson-nav li { flex: 0 0 auto; white-space: nowrap; }
  .lesson-panel { flex-basis: auto; width: 100%; }

  /* status bar: drop the hover hint (no mouse), keep the credit */
  #statusHover { display: none; }
  .statusbar { justify-content: flex-end; padding: 6px 12px; }
}

@media (max-width: 420px) {
  .field-grid, .check-grid { grid-template-columns: 1fr; }
  .chart-wrap { height: 96vw; }
}