/* ------------------------------------------------------------------
   Interactive teaching aids (교보재) for lecture pages.

   Loaded after lecture-lab.css, whose tokens it reuses. Every rule is
   scoped under .app so it cannot reach the site nav or footer.
   ------------------------------------------------------------------ */

.app {
  max-width: 1120px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 28px;
  font-family: var(--sans);
}

.app h1, .app h2, .app h3, .app p { margin: 0; }
.app p { max-width: 70ch; }
.app b { font-weight: 600; }

.app .masthead {
  padding-top: 40px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.app .eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .13em;
  text-transform: uppercase;
  color: var(--ink-3);
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
}

.app .eyebrow b { color: var(--accent); }

.app .masthead h1 {
  font-size: clamp(32px, 5.4vw, 46px);
  line-height: 1.12;
  letter-spacing: -.025em;
  text-wrap: balance;
}

.app .standfirst { font-size: 17px; color: var(--ink-2); max-width: 64ch; }
.app .standfirst strong { color: var(--ink); }

/* ---- module launcher ---- */

.app .launcher {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.app .tile {
  position: relative;
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 4px 14px;
  align-items: start;
  padding: 16px 16px 14px;
  border: 1px solid var(--rule);
  border-radius: 14px;
  background: var(--surface);
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: border-color .15s ease, box-shadow .15s ease, transform .15s ease;
}

.app .tile:hover { border-color: var(--rule-strong); box-shadow: var(--shadow); transform: translateY(-1px); }
.app .tile:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.app .tile[aria-selected="true"] {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent) inset, var(--shadow);
}

.app .tile-ico {
  grid-row: span 3;
  width: 44px;
  height: 44px;
  border-radius: 11px;
  background: var(--accent-soft);
  color: var(--accent-ink);
  display: grid;
  place-items: center;
  font-family: var(--mono);
  font-weight: 700;
  font-size: 15px;
}

.app .tile-t { font-weight: 700; font-size: 15.5px; letter-spacing: -.01em; line-height: 1.35; }
.app .tile-d { font-size: 13.5px; color: var(--ink-2); line-height: 1.45; }

.app .tile-meta {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-top: 4px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--ink-3);
}

.app .tile-status {
  margin-left: auto;
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--rule);
}

.app .tile.done .tile-status {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
}

.app .progress {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 13.5px;
  color: var(--ink-2);
}

.app .progress-bar {
  flex: 1;
  height: 6px;
  border-radius: 999px;
  background: var(--surface-2);
  border: 1px solid var(--rule);
  overflow: hidden;
}

.app .progress-bar > span {
  display: block;
  height: 100%;
  width: 0;
  background: var(--accent);
  transition: width .3s ease;
}

/* ---- module panel ---- */

.app .module {
  border: 1px solid var(--rule);
  border-radius: 18px;
  background: var(--surface);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.app .module[hidden] { display: none; }
.app .module { scroll-margin-top: 92px; }

.app .mod-head {
  padding: 22px 24px 18px;
  border-bottom: 1px solid var(--rule);
  display: flex;
  flex-direction: column;
  gap: 8px;
  background: linear-gradient(180deg, var(--surface-2), var(--surface));
}

.app .mod-tag {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-3);
  display: flex;
  flex-wrap: wrap;
  gap: 4px 14px;
}

.app .mod-tag b { color: var(--accent); }
.app .mod-head h2 { font-size: 23px; letter-spacing: -.02em; }
.app .mod-head p { color: var(--ink-2); font-size: 15px; }

.app .goal {
  display: inline-flex;
  align-self: flex-start;
  gap: 8px;
  align-items: baseline;
  padding: 6px 12px;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-size: 13.5px;
  font-weight: 600;
}

.app .goal::before { content: "목표"; white-space: nowrap; font-family: var(--mono); font-size: 11px; letter-spacing: .1em; opacity: .8; }

.app .mod-body {
  padding: 22px 24px 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.app .mod-foot {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 14px 24px;
  border-top: 1px solid var(--rule);
  background: var(--surface-2);
}

.app h3.sub {
  font-size: 16.5px;
  letter-spacing: -.01em;
  display: flex;
  gap: 10px;
  align-items: baseline;
}

.app h3.sub .n {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--accent);
}

/* ---- generic widgets ---- */

.app .btn {
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  padding: 8px 14px;
  border-radius: 9px;
  border: 1px solid var(--rule-strong);
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
  transition: background .15s ease, border-color .15s ease, color .15s ease;
  white-space: nowrap;
}

.app .btn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent-ink); }
.app .btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.app .btn:disabled { opacity: .45; cursor: not-allowed; }

.app .btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.app .btn.primary:hover:not(:disabled) { background: var(--accent-ink); color: #fff; }
.app .btn.warn { border-color: var(--signal); color: var(--signal); }
.app .btn.warn:hover:not(:disabled) { background: var(--signal-soft); color: var(--signal); border-color: var(--signal); }
.app .btn.ghost { border-color: transparent; background: transparent; color: var(--ink-2); }

.app .row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.app .row.spread { justify-content: space-between; }

.app .seg {
  display: inline-flex;
  border: 1px solid var(--rule-strong);
  border-radius: 9px;
  overflow: hidden;
}

.app .seg button {
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  padding: 6px 11px;
  border: 0;
  border-right: 1px solid var(--rule);
  background: var(--surface);
  color: var(--ink-2);
  cursor: pointer;
}

.app .seg button:last-child { border-right: 0; }
.app .seg button[aria-pressed="true"] { background: var(--accent-soft); color: var(--accent-ink); }
.app .seg button:focus-visible { outline: 2px solid var(--accent); outline-offset: -2px; }

.app .chips { display: flex; flex-wrap: wrap; gap: 6px; }

.app .chip {
  font: inherit;
  font-size: 13.5px;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--rule-strong);
  background: var(--surface);
  color: var(--ink-2);
  cursor: pointer;
}

.app .chip i {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--c, var(--accent));
  font-style: normal;
}

.app .chip[aria-pressed="true"] {
  border-color: var(--c, var(--accent));
  color: var(--ink);
  box-shadow: 0 0 0 1px var(--c, var(--accent)) inset;
}

.app .chip:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.app label.field { display: flex; flex-direction: column; gap: 5px; font-size: 13.5px; color: var(--ink-2); }
.app label.field span.u { color: var(--ink-3); font-family: var(--mono); font-size: 12px; }

.app input[type="number"], .app input[type="text"], .app select, .app textarea {
  font: inherit;
  font-size: 15px;
  padding: 8px 10px;
  border: 1px solid var(--rule-strong);
  border-radius: 8px;
  background: var(--surface);
  color: var(--ink);
  min-width: 0;
}

.app textarea { width: 100%; min-height: 96px; resize: vertical; line-height: 1.6; }
.app input:focus-visible, .app select:focus-visible, .app textarea:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

.app input[type="range"] { width: 100%; accent-color: var(--accent); }

.app .note {
  font-size: 13.5px;
  color: var(--ink-2);
}

.app .callout {
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 10px 10px 0;
  padding: 12px 16px;
  font-size: 14.5px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.app .callout .h {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--accent-ink);
}

.app .callout.signal { border-left-color: var(--signal); background: var(--signal-soft); }
.app .callout.signal .h { color: var(--signal); }

.app .formula {
  font-family: var(--mono);
  font-size: 15px;
  padding: 10px 14px;
  border: 1px solid var(--rule);
  border-radius: 10px;
  background: var(--surface-2);
  display: flex;
  flex-wrap: wrap;
  gap: 6px 28px;
}

.app .feedback { font-size: 14px; padding: 9px 12px; border-radius: 8px; display: none; line-height: 1.55; }
.app .feedback.show { display: block; }
.app .feedback.ok { background: var(--accent-soft); color: var(--accent-ink); }
.app .feedback.bad { background: var(--signal-soft); color: var(--signal); }
.app .feedback.info { background: var(--surface-2); color: var(--ink-2); border: 1px solid var(--rule); }

.app .tablewrap { overflow-x: auto; border: 1px solid var(--rule); border-radius: 10px; background: var(--surface); }
.app table { border-collapse: collapse; width: 100%; font-size: 14px; }
.app th {
  text-align: left;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .06em;
  color: var(--ink-3);
  padding: 9px 12px;
  border-bottom: 1px solid var(--rule);
  white-space: nowrap;
  background: var(--surface-2);
}
.app th button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; letter-spacing: inherit; }
.app th button:hover { color: var(--accent-ink); }
.app td { padding: 9px 12px; border-bottom: 1px solid var(--rule); vertical-align: top; }
.app td.num { font-family: var(--mono); font-size: 13px; white-space: nowrap; }
.app tr:last-child td { border-bottom: 0; }
.app td .dot { display: inline-block; width: 9px; height: 9px; border-radius: 50%; margin-right: 7px; }
.app .empty-row td { color: var(--ink-3); text-align: center; font-size: 13.5px; }

/* ---- calculator (module 1) ---- */

.app .calc {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 18px;
}

.app .sliders { display: flex; flex-direction: column; gap: 14px; }
.app .slider-row { display: grid; grid-template-columns: 1fr auto; gap: 2px 10px; align-items: baseline; }
.app .slider-row .lbl { font-size: 14px; font-weight: 600; }
.app .slider-row .val { font-family: var(--mono); font-size: 14px; color: var(--accent-ink); }
.app .slider-row input { grid-column: 1 / -1; }

.app .outs { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; align-content: start; }

.app .out {
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 10px 12px;
  background: var(--surface-2);
}

.app .out .k { font-size: 12.5px; color: var(--ink-2); }
.app .out .v { font-family: var(--mono); font-size: 19px; font-weight: 600; color: var(--ink); }
.app .out .v small { font-size: 12px; color: var(--ink-3); font-weight: 500; }
.app .out.wide { grid-column: 1 / -1; }

.app .problem {
  border: 1px solid var(--rule-strong);
  border-radius: 12px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.app .problem .q { font-size: 15.5px; line-height: 1.65; }
.app .problem .answer-row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.app .problem .answer-row input { width: 160px; }
.app .score { font-family: var(--mono); font-size: 13px; color: var(--ink-2); }

/* ---- tensile tester ---- */

.app .tester { display: flex; flex-direction: column; gap: 14px; }

.app .t-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 14px;
  align-items: start;
}

.app .pane {
  border: 1px solid var(--rule);
  border-radius: 12px;
  background: var(--surface);
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-width: 0;
}

.app .pane-h {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: none;
  color: var(--ink-3);
  display: flex;
  justify-content: space-between;
  gap: 8px;
  align-items: center;
}

.app .graph { position: relative; width: 100%; height: 380px; }
.app .graph canvas { display: block; width: 100%; height: 100%; }
.app .graph.short { height: 320px; }

.app .cursor-read {
  position: absolute;
  right: 18px;
  top: 18px;
  font-family: var(--mono);
  font-size: 12px;
  padding: 4px 8px;
  border-radius: 6px;
  background: rgba(255, 255, 255, .92);
  border: 1px solid var(--rule);
  color: var(--ink);
  pointer-events: none;
  display: none;
}

.app .readouts { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }

.app .ro { border: 1px solid var(--rule); border-radius: 9px; padding: 7px 10px; background: var(--surface-2); }
.app .ro .k { font-size: 11.5px; color: var(--ink-2); }
.app .ro .v { font-family: var(--mono); font-size: 16px; font-weight: 600; }
.app .ro.el .v { color: #1b5fa8; }
.app .ro.pl .v { color: var(--signal); }

.app .stages {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  border: 1px solid var(--rule);
  border-radius: 9px;
  overflow: hidden;
}

.app .stages span {
  text-align: center;
  font-size: 12px;
  font-weight: 600;
  padding: 6px 2px;
  color: var(--ink-3);
  border-right: 1px solid var(--rule);
  background: var(--surface);
}

.app .stages span:last-child { border-right: 0; }
.app .stages span.past { color: var(--ink-2); background: var(--surface-2); }
.app .stages span.now { color: #fff; background: var(--accent); }
.app .stages span.now.bad { background: var(--signal); }

.app .status {
  font-size: 14px;
  line-height: 1.55;
  min-height: 3.1em;
  padding: 9px 12px;
  border-radius: 9px;
  background: var(--surface-2);
  border: 1px solid var(--rule);
}

.app .specimen svg, .app .atoms svg { width: 100%; height: auto; display: block; }

.app .atoms-cap { font-size: 13px; color: var(--ink-2); line-height: 1.5; }

.app .legend { display: flex; flex-wrap: wrap; gap: 4px 14px; font-size: 12px; color: var(--ink-2); }
.app .legend i { display: inline-block; width: 14px; height: 3px; vertical-align: middle; margin-right: 5px; border-radius: 2px; }

.app .lock {
  position: relative;
}

.app .lock.locked > .tester { opacity: .35; pointer-events: none; filter: grayscale(.6); }

.app .lock-msg {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  z-index: 3;
  pointer-events: none;
}

.app .lock-msg span {
  padding: 12px 18px;
  border-radius: 10px;
  background: var(--ink);
  color: #fff;
  font-weight: 600;
  font-size: 14.5px;
}

.app .lock:not(.locked) .lock-msg { display: none; }

/* ---- POE (module 3) ---- */

.app .poe-steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }

.app .poe-steps div {
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 13px;
  color: var(--ink-3);
  background: var(--surface);
}

.app .poe-steps div b { display: block; font-size: 15px; color: var(--ink-3); }
.app .poe-steps div.on { border-color: var(--accent); background: var(--accent-soft); color: var(--accent-ink); }
.app .poe-steps div.on b { color: var(--accent-ink); }
.app .poe-steps div.fin b::after { content: " ✓"; color: var(--accent); }

.app fieldset.mc {
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 14px 16px;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.app fieldset.mc legend { font-size: 15px; font-weight: 600; padding: 0 6px; line-height: 1.5; }
.app fieldset.mc .opt {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 8px 10px;
  border-radius: 8px;
  border: 1px solid transparent;
  cursor: pointer;
  font-size: 14.5px;
  line-height: 1.5;
}
.app fieldset.mc .opt:hover { background: var(--surface-2); }
.app fieldset.mc .opt input { margin-top: 4px; accent-color: var(--accent); }
.app fieldset.mc .opt.correct { border-color: var(--accent); background: var(--accent-soft); }
.app fieldset.mc .opt.wrong { border-color: var(--signal); background: var(--signal-soft); }
.app fieldset.mc:disabled .opt { cursor: default; }

.app .compare td.you { color: var(--ink-2); }

/* ---- quiz (module 6) ---- */

.app .quiz { display: flex; flex-direction: column; gap: 14px; }
.app .quiz .qn { font-family: var(--mono); color: var(--accent); margin-right: 6px; }
.app .quiz .num-ans { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; padding: 4px 6px; }
.app .quiz .num-ans input { width: 150px; }

/* ---- instructor notes ---- */

.app details.guide {
  border: 1px solid var(--rule);
  border-radius: 14px;
  background: var(--surface);
}

.app details.guide > summary {
  cursor: pointer;
  padding: 14px 18px;
  font-weight: 700;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 12px;
}

.app details.guide > summary::-webkit-details-marker { display: none; }
.app details.guide > summary::after { content: "펼치기 +"; font-family: var(--mono); font-size: 12px; color: var(--ink-3); font-weight: 500; }
.app details.guide[open] > summary::after { content: "접기 −"; }
.app details.guide > div { padding: 0 18px 18px; display: flex; flex-direction: column; gap: 14px; font-size: 14.5px; }
.app details.guide ol, .app details.guide ul { margin: 0; padding-left: 20px; display: flex; flex-direction: column; gap: 4px; }

.app .colophon {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--ink-3);
  letter-spacing: .03em;
  line-height: 1.8;
}

@media (max-width: 960px) {
  .app .launcher { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .app .t-grid { grid-template-columns: 1fr; }
  .app .side { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
}

@media (max-width: 680px) {
  .app .launcher { gap: 8px; }
  .app .tile { grid-template-columns: 1fr; padding: 12px; }
  .app .tile-ico { grid-row: auto; width: 34px; height: 34px; font-size: 13px; }
  .app .tile-d { display: none; }
  .app .calc { grid-template-columns: 1fr; }
  .app .side { grid-template-columns: 1fr; }
  .app .poe-steps { grid-template-columns: 1fr; }
  .app .mod-head, .app .mod-body, .app .mod-foot { padding-left: 14px; padding-right: 14px; }
  .app .graph { height: 300px; }
  .app .graph.short { height: 260px; }
  .app .stages span { font-size: 10.5px; }
}

@media (prefers-reduced-motion: reduce) {
  .app * { transition: none !important; }
}

/* ---- XRD aid (교보재 02) ---- */

.app .x-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 14px;
  align-items: start;
}

.app .crystal { position: relative; width: 100%; aspect-ratio: 1 / 1; max-height: 440px; touch-action: none; cursor: grab; }
.app .crystal:active { cursor: grabbing; }
.app .crystal canvas { display: block; width: 100%; height: 100%; }
.app .crystal-hint {
  position: absolute; left: 10px; bottom: 8px;
  font-size: 11.5px; color: var(--ink-3); pointer-events: none;
}
.app .crystal-tag {
  position: absolute; right: 10px; top: 8px;
  font-family: var(--mono); font-size: 18px; font-weight: 700; color: var(--accent-ink);
  pointer-events: none;
}

.app .big-read { font-family: var(--mono); font-size: 26px; font-weight: 700; letter-spacing: -.01em; }
.app .big-read small { font-size: 13px; color: var(--ink-3); font-weight: 500; }

.app .meter { height: 10px; border-radius: 999px; background: var(--surface-2); border: 1px solid var(--rule); overflow: hidden; }
.app .meter > span { display: block; height: 100%; width: 0; background: var(--accent); transition: width .08s linear; }
.app .meter.bad > span { background: var(--signal); }

.app .angle-row { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: 10px; align-items: center; }
.app .angle-row input[type="number"] { width: 92px; font-family: var(--mono); }

.app .peakcard { border: 1px solid var(--rule); border-radius: 10px; padding: 10px 12px; background: var(--surface-2); font-size: 14px; line-height: 1.6; min-height: 5.2em; }
.app .peakcard.hit { border-color: var(--accent); background: var(--accent-soft); }
.app .peakcard .hkl { font-family: var(--mono); font-weight: 700; color: var(--accent-ink); font-size: 16px; }

.app td.hidden-val { color: var(--ink-3); }
.app tr.found td { background: var(--accent-soft); }

.app .powder svg, .app .bragg svg, .app .diffr svg, .app .phasor svg { width: 100%; height: auto; display: block; }

.app .num-in { width: 110px; }
.app .ok-mark { color: var(--accent); font-weight: 700; }
.app .bad-mark { color: var(--signal); font-weight: 700; }

@media (max-width: 960px) {
  .app .x-grid { grid-template-columns: 1fr; }
}