/* Light theme is the default; dark is applied only when the OS/browser asks
   for it (prefers-color-scheme), never assumed. Every colour token used for
   meaning (severity, leaked/protected, captured/not) is always paired with an
   icon and a word in the markup — colour alone never carries information. */
:root {
  --bg: #f4f6f9;
  --panel: #ffffff;
  --edge: #d7dee6;
  --ink: #1b232c;
  --muted: #56616c;
  --accent: #0969da;
  --accent-ink: #ffffff;

  --good: #146c43;
  --good-bg: #e6f4ea;
  --bad: #b3261e;
  --bad-bg: #fbeae8;
  --warn: #8a5300;
  --warn-bg: #fff3cd;
  --low: #0b7285;
  --low-bg: #e3f6f5;
  --info: #3b4fc4;
  --info-bg: #ecefff;

  /* The 2G track badge needs its own token: the dark-theme pink (#ff9db1)
     reads fine on a near-black background but fails WCAG AA (~1.8:1) against
     the light theme's pale panel/bg, so light and dark get different values
     rather than sharing one hardcoded hex. */
  --track-2g: #c2255c;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1216;
    --panel: #171c23;
    --edge: #2a323d;
    --ink: #e6edf3;
    --muted: #9aa7b4;
    --accent: #6cc6ff;
    --accent-ink: #041018;

    --good: #4ec98a;
    --good-bg: rgba(78, 201, 138, 0.14);
    --bad: #ff7b72;
    --bad-bg: rgba(255, 123, 114, 0.16);
    --warn: #ffb454;
    --warn-bg: rgba(255, 180, 84, 0.16);
    --low: #4dd4c4;
    --low-bg: rgba(77, 212, 196, 0.14);
    --info: #8ab4f8;
    --info-bg: rgba(138, 180, 248, 0.14);

    --track-2g: #ff9db1;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

header, main, footer { max-width: 1100px; margin: 0 auto; padding: 0 20px; }
header { padding-top: 28px; }

.skip-link {
  position: absolute; left: -999px; top: auto;
  background: var(--accent); color: var(--accent-ink);
  padding: 8px 14px; border-radius: 0 0 8px 0; z-index: 100;
}
.skip-link:focus { left: 0; top: 0; }

/* Skip-link target and the stage heading (focused programmatically after a
   drill loads, see app.js) are otherwise-inert headings made focusable with
   tabindex="-1" purely so focus actually moves there — give them the same
   visible ring every other focusable element gets. */
[tabindex="-1"]:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

h1 { margin: 0; font-size: 26px; letter-spacing: .3px; }
h2 { font-size: 19px; margin: 0 0 6px; }
.tag { color: var(--muted); margin: 4px 0 16px; }

/* ---- About / Workshop panels ------------------------------------------ */
#about, #workshop {
  background: var(--panel); border: 1px solid var(--edge); border-radius: 10px;
  padding: 10px 14px; margin-bottom: 18px;
}
#about summary, #workshop summary {
  cursor: pointer; font-weight: 600; padding: 4px 0; list-style: revert;
}
#about summary:focus-visible, #workshop summary:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 2px;
}
.about-body, .workshop-body { margin-top: 8px; max-width: 72ch; }
.about-body p, .workshop-body > p { color: var(--muted); margin: 0 0 10px; }
.about-body a, .workshop-body a { color: var(--accent); }
.workshop-body h2 { font-size: 14px; font-weight: 600; margin: 18px 0 6px; }
.workshop-body h2:first-of-type { margin-top: 14px; }
.checkbox-label {
  display: flex; align-items: center; gap: 8px; margin: 4px 0 14px; cursor: pointer;
}
.checkbox-label input { width: 16px; height: 16px; }
#scoreboard-list { margin: 6px 0 14px; }
#scoreboard-list li { padding: 7px 0; border-bottom: 1px solid var(--edge); }
#scoreboard-list li:last-child { border-bottom: none; }
#scoreboard-list li.captured .flag-badge { background: var(--good-bg); color: var(--good); }
#scoreboard-list li.not-captured .flag-badge {
  background: var(--bg); color: var(--muted); border: 1px solid var(--edge);
}
#scoreboard-list li.captured b { color: var(--good); }

/* ---- The arc strip (decorative summary of the whole story) ----------- */
.arc {
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px;
  list-style: none; margin: 0 0 24px; padding: 0;
}
.arc li { display: flex; flex-direction: column; align-items: center; text-align: center; }
.arc-step {
  display: inline-block; background: var(--panel); border: 1px solid var(--edge);
  border-radius: 999px; padding: 6px 16px; font-weight: 700; font-size: 13px;
}
.arc small { color: var(--muted); font-size: 11px; margin-top: 3px; }
.arc-arrow { color: var(--muted); font-size: 16px; padding-bottom: 16px; }

/* ---- Guided course ------------------------------------------------------ */
#course {
  margin-bottom: 22px; padding-bottom: 20px; border-bottom: 1px solid var(--edge);
}
.course-progress {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px 16px; margin: 2px 0 10px;
}
.course-position { font-weight: 700; }
.course-completed {
  color: var(--muted); font-size: 12.5px; background: var(--bg); border: 1px solid var(--edge);
  border-radius: 999px; padding: 3px 10px;
}
.course-framing { max-width: 70ch; margin: 0 0 14px; }

/* ---- Catalogue / scenario groups -------------------------------------- */
.catalogue-hint, .course-hint { color: var(--muted); max-width: 74ch; margin: 0 0 18px; }

.track-group { margin-bottom: 20px; }
.track-group h3 {
  font-size: 13px; text-transform: uppercase; letter-spacing: .5px;
  color: var(--muted); margin: 0 0 10px; padding-bottom: 6px;
  border-bottom: 1px solid var(--edge);
}
.track-row { display: flex; flex-wrap: wrap; gap: 10px; }

.scenario {
  display: flex; flex-direction: column; align-items: flex-start; gap: 4px;
  text-align: left; background: var(--panel); color: var(--ink);
  border: 1px solid var(--edge); border-radius: 10px; padding: 10px 14px;
  cursor: pointer; font: inherit; width: 260px; max-width: 100%;
}
.scenario:hover { border-color: var(--accent); }
.scenario:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.scenario.active {
  border-color: var(--accent); border-width: 2px; padding: 9px 13px;
  box-shadow: 0 0 0 1px var(--accent) inset;
}
.scenario-title { font-weight: 700; }
.scenario-brief { color: var(--muted); font-size: 12.5px; line-height: 1.4; }

.track-badge {
  font-size: 10px; font-weight: 700; letter-spacing: .4px; text-transform: uppercase;
  padding: 2px 7px; border-radius: 999px; background: var(--bg); color: var(--muted);
  border: 1px solid var(--edge);
}
.track-2g .track-badge, .track-badge.track-2g { color: var(--track-2g); border-color: var(--track-2g); }
.track-4g .track-badge, .track-badge.track-4g { color: var(--warn); border-color: var(--warn); }
.track-5g .track-badge, .track-badge.track-5g { color: var(--good); border-color: var(--good); }
.track-defend .track-badge, .track-badge.track-defend { color: var(--accent); border-color: var(--accent); }

/* ---- Stage ------------------------------------------------------------- */
#stage { margin-top: 8px; padding-top: 22px; border-top: 1px solid var(--edge); }
.brief { color: var(--muted); max-width: 70ch; }

.controls { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0 10px; }
button#run, button#reset, button#course-open, button#course-prev, button#course-next,
button#scoreboard-reset, button#print-worksheet {
  border-radius: 8px; padding: 10px 18px; cursor: pointer;
  border: 1px solid var(--edge); font-size: 14px; font: inherit;
}
button#run, button#course-open {
  background: var(--accent); color: var(--accent-ink); border-color: var(--accent); font-weight: 700;
}
button#run:hover, button#course-open:hover { filter: brightness(1.05); }
button.secondary { background: transparent; color: var(--ink); }
button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.status {
  color: var(--muted); font-size: 13.5px; margin: 0 0 16px; min-height: 1.4em;
}

.panels { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
@media (max-width: 860px) { .panels { grid-template-columns: 1fr; } }

.panel { background: var(--panel); border: 1px solid var(--edge); border-radius: 10px; padding: 14px; }
.panel h3 {
  margin: 0 0 8px; font-size: 13px; text-transform: uppercase;
  letter-spacing: .6px; color: var(--muted);
}
.panel h3 + h3 { margin-top: 16px; }

ul, ol { margin: 0; padding-left: 0; list-style: none; }
#cells li, #findings li, #flags li { padding: 8px 0; border-bottom: 1px solid var(--edge); }
#cells li:last-child, #findings li:last-child, #flags li:last-child { border-bottom: none; }
#events li { padding: 9px 0; border-bottom: 1px solid var(--edge); }
#events li:last-child { border-bottom: none; }

.muted { color: var(--muted); }
.good { color: var(--good); }
.bad { color: var(--bad); }

/* ---- Cells -------------------------------------------------------------- */
#cells li { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 10px; }
.cell-id { font-weight: 700; }
.cell-rat {
  font-size: 11px; font-weight: 700; background: var(--bg); color: var(--muted);
  border: 1px solid var(--edge); border-radius: 4px; padding: 1px 5px;
}
.cell-signal, .cell-area, .cell-plmn { color: var(--muted); font-size: 13px; }
.camped-cell { background: var(--info-bg); border-radius: 6px; margin: 0 -6px; padding: 8px 6px !important; }
.camped-badge { color: var(--accent); font-size: 12px; font-weight: 600; }

/* ---- Events --------------------------------------------------------------- */
.event-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px; margin-bottom: 3px; }
code { color: var(--accent); font-size: 12px; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }
.dir {
  font-size: 11px; padding: 1px 6px; border-radius: 4px; background: var(--bg);
  color: var(--muted); border: 1px solid var(--edge); white-space: nowrap;
}
.dir-net_to_ue { color: var(--warn); border-color: var(--warn); }
.dir-ue_to_net { color: var(--good); border-color: var(--good); }
.dir-observed { color: var(--info); border-color: var(--info); }

/* ---- Findings: colour + icon + word, never colour alone ------------------ */
.sev-badge {
  display: inline-flex; align-items: center; gap: 4px; font-weight: 700;
  font-size: 12px; padding: 2px 8px; border-radius: 999px; margin-right: 6px;
}
.sev-high { border-left: 4px solid var(--bad); padding-left: 10px; }
.sev-high .sev-badge { background: var(--bad-bg); color: var(--bad); }
.sev-medium { border-left: 4px solid var(--warn); padding-left: 10px; }
.sev-medium .sev-badge { background: var(--warn-bg); color: var(--warn); }
.sev-low { border-left: 4px solid var(--low); padding-left: 10px; }
.sev-low .sev-badge { background: var(--low-bg); color: var(--low); }
.sev-info { border-left: 4px solid var(--info); padding-left: 10px; }
.sev-info .sev-badge { background: var(--info-bg); color: var(--info); }

/* ---- Flags ------------------------------------------------------------- */
.flags, #instructor-notes, #tinker { margin-top: 14px; }
.flag-badge {
  display: inline-flex; align-items: center; gap: 4px; font-weight: 700;
  font-size: 12px; padding: 2px 8px; border-radius: 999px; margin-right: 6px;
}
#flags li.captured .flag-badge { background: var(--good-bg); color: var(--good); }
#flags li.not-captured .flag-badge { background: var(--bg); color: var(--muted); border: 1px solid var(--edge); }
#flags li.captured b { color: var(--good); }

/* ---- Instructor notes: a facilitator-only callout, visually distinct from
   the learner-facing panels above it ------------------------------------- */
#instructor-notes { border-left: 4px solid var(--accent); }
#instructor-notes h3 { color: var(--accent); }
#instructor-notes-list { list-style: disc; padding-left: 20px; }
#instructor-notes-list li { padding: 3px 0; }

/* ---- Tinker panel: an opt-in <details>, styled like the panels above --- */
#tinker summary { cursor: pointer; font-weight: 600; list-style: revert; }
#tinker summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.tinker-body { margin-top: 10px; }
.tinker-body > p { color: var(--muted); max-width: 70ch; }
.tinker-controls {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin: 10px 0;
}
.tinker-controls select {
  padding: 6px 8px; border-radius: 6px; border: 1px solid var(--edge);
  background: var(--panel); color: var(--ink); font: inherit; font-size: 13.5px;
}
.tinker-controls select:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.tinker-readout { font-size: 13px; margin: 6px 0 0; }

footer { color: var(--muted); padding: 30px 20px 44px; font-size: 13px; }
footer a { color: var(--accent); }

/* ---- Print worksheet: hidden on screen, shown only via @media print ---- */
#worksheet { display: none; }

@media print {
  body { background: #fff; color: #000; }
  .skip-link, header, #course, #catalogue, #stage, footer { display: none !important; }
  #worksheet { display: block !important; max-width: none; padding: 0 24px; }
  #worksheet h2 { font-size: 20px; margin: 0 0 6px; }
  #worksheet > p { margin: 0 0 20px; color: #333; }
  #worksheet-list { list-style: decimal; padding-left: 22px; margin: 0; }
  #worksheet-list li { break-inside: avoid; margin-bottom: 22px; padding-bottom: 12px; border-bottom: 1px solid #999; }
  #worksheet-list h3 { font-size: 14px; margin: 0 0 4px; }
  #worksheet-list h3 small { font-weight: normal; color: #333; }
  #worksheet-list p { margin: 0 0 6px; font-size: 12.5px; color: #000; }
  .worksheet-framing { color: #333 !important; }
  .worksheet-rule { border-bottom: 1px solid #bbb; height: 20px; margin: 0 0 4px; }
}

/* ---- Mobile ------------------------------------------------------------- */
@media (max-width: 560px) {
  header, main, footer { padding: 0 14px; }
  h1 { font-size: 22px; }
  .scenario { width: 100%; }
  .arc { gap: 6px; }
  .arc-step { padding: 5px 12px; font-size: 12px; }
  .arc-arrow { display: none; }
  .controls { flex-direction: column; align-items: stretch; }
  .controls button { width: 100%; }
  .course-progress { flex-direction: column; align-items: flex-start; gap: 6px; }
  .tinker-controls { flex-direction: column; align-items: stretch; }
  .tinker-controls select, .tinker-controls button { width: 100%; }
}