/* EDU-REGEX · Regex Playground — same visual language as EDU-16 and EDU-NET:
   a tribute to Olivetti's desktop machines (Programma 101): warm putty chassis,
   engraved labels, mechanical keycaps, and dark phosphor-green display insets
   for everything the machine "shows" (here: the automaton, the tape, the log). */

:root {
  --chassis: #e3ddcd;
  --chassis-deep: #d3ccb8;
  --panel: #f1ede1;
  --panel-edge: #c4bca6;
  --ink: #34322b;
  --ink-soft: #7c7663;
  --olivetti: #c8442c;
  --olivetti-dark: #a83620;
  --screen: #20251e;
  --screen-edge: #14170f;
  --phosphor: #93e8bb;
  --phosphor-dim: #5d8f74;
  --phosphor-soft: #b9f0d3;
  --amber: #e4b04a;
  --led-off: #4a3f38;
  --pass: #3d7a4f;
  --fail: #b23a2c;
  --mono: ui-monospace, "SF Mono", "Cascadia Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: "Avenir Next", "Segoe UI", system-ui, -apple-system, sans-serif;
  /* capture-group colours */
  --cap-0: #7ad4e8;
  --cap-1: #e4b04a;
  --cap-2: #c8a6e8;
  --cap-3: #f0b8a0;
  --cap-4: #93e8bb;
  --cap-5: #e8e3c0;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }
html, body { height: 100%; }

body {
  font-family: var(--sans);
  color: var(--ink);
  background: radial-gradient(ellipse at 30% -10%, #efeadb 0%, var(--chassis) 55%, var(--chassis-deep) 100%);
  display: flex;
  flex-direction: column;
}

button { font: inherit; cursor: pointer; }
a { color: var(--olivetti-dark); }

/* ---------- header ---------- */

.top {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; padding: 0.7rem 1.2rem;
  border-bottom: 2px solid var(--panel-edge); flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: 0.75rem; }
.brand-mark {
  font-family: var(--mono); font-weight: 700; font-size: 0.95rem;
  color: var(--panel); background: var(--olivetti); border-radius: 6px;
  padding: 0.45rem 0.5rem; letter-spacing: 0.02em;
  box-shadow: inset 0 -2px 0 rgb(0 0 0 / 0.25);
}
.brand-text h1 { font-family: var(--mono); font-size: 1.15rem; letter-spacing: 0.06em; line-height: 1.1; }
.brand-sub { font-size: 0.62rem; letter-spacing: 0.3em; color: var(--ink-soft); font-weight: 600; vertical-align: 0.15em; }
.brand-tag { font-size: 0.72rem; color: var(--ink-soft); font-style: italic; }
.top-nav { display: flex; align-items: center; gap: 0.5rem; }
.lang-switch { display: flex; border: 1px solid var(--panel-edge); border-radius: 6px; overflow: hidden; margin-left: 0.4rem; }
.lang-switch button { border: 0; background: var(--panel); color: var(--ink-soft); font-size: 0.7rem; font-weight: 700; letter-spacing: 0.08em; padding: 0.35rem 0.55rem; }
.lang-switch button.active { background: var(--ink); color: var(--panel); }

/* ---------- keycap buttons ---------- */

.btn {
  font-size: 0.78rem; font-weight: 600; letter-spacing: 0.06em; color: var(--ink);
  background: linear-gradient(#faf7ee, #eae5d5); border: 1px solid var(--panel-edge);
  border-radius: 7px; padding: 0.42rem 0.85rem;
  box-shadow: 0 2px 0 var(--panel-edge), 0 3px 4px rgb(0 0 0 / 0.08);
  transition: transform 60ms, box-shadow 60ms; display: inline-block;
}
.btn:hover { filter: brightness(1.03); }
.btn:active { transform: translateY(2px); box-shadow: 0 0 0 var(--panel-edge); }
.btn:disabled { opacity: 0.45; cursor: default; transform: none; }
.btn-primary { color: #fff; background: linear-gradient(#d9563c, var(--olivetti)); border-color: var(--olivetti-dark); box-shadow: 0 2px 0 var(--olivetti-dark), 0 3px 4px rgb(0 0 0 / 0.15); }
.btn-ghost { background: transparent; box-shadow: none; border-color: transparent; color: var(--ink-soft); }
.btn-ghost:active { transform: none; }
.btn-mini { font-size: 0.64rem; padding: 0.28rem 0.5rem; }
:focus-visible { outline: 2px solid var(--olivetti); outline-offset: 2px; }

/* ---------- cards & engraved labels ---------- */

.card {
  background: var(--panel); border: 1px solid var(--panel-edge); border-radius: 10px;
  box-shadow: 0 1px 0 #fff inset, 0 4px 10px rgb(60 50 20 / 0.08);
  padding: 0.7rem 0.8rem 0.8rem;
}
.card-head { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 0.55rem; }
.card-title, .lesson-eyebrow {
  font-size: 0.62rem; font-weight: 700; letter-spacing: 0.26em; text-transform: uppercase;
  color: var(--ink-soft); text-shadow: 0 1px 0 rgb(255 255 255 / 0.7);
}
.chip { border-radius: 4px; padding: 0.08rem 0.45rem; white-space: nowrap; }
.chip-rule { font-family: var(--mono); font-size: 0.68rem; background: var(--chassis-deep); border: 1px solid var(--panel-edge); color: var(--ink); }

/* ---------- lesson panel ---------- */

.lesson { display: flex; flex-direction: column; gap: 0.7rem; }
.lesson-eyebrow { display: flex; align-items: center; gap: 0.5rem; }
.lesson-title { font-size: 1.25rem; line-height: 1.2; }
.lesson-text { font-size: 0.86rem; line-height: 1.55; }
.lesson-text p + p { margin-top: 0.5rem; }
.lesson-text code, .goal code, .hint code, .help-body code {
  font-family: var(--mono); font-size: 0.85em; background: rgb(60 50 20 / 0.08);
  border-radius: 4px; padding: 0.05em 0.3em;
}
.lesson-text pre, .help-body pre {
  font-family: var(--mono); font-size: 0.78rem; line-height: 1.5;
  background: var(--screen); color: var(--phosphor); border-radius: 7px;
  padding: 0.6rem 0.8rem; overflow-x: auto; margin: 0.4rem 0;
}
.goal { font-size: 0.86rem; line-height: 1.5; background: rgb(200 68 44 / 0.07); border-left: 3px solid var(--olivetti); border-radius: 0 7px 7px 0; padding: 0.5rem 0.7rem; }
.goal-label { display: block; font-size: 0.6rem; font-weight: 700; letter-spacing: 0.26em; text-transform: uppercase; color: var(--olivetti); margin-bottom: 0.15rem; }
.rule-chips { display: flex; flex-wrap: wrap; gap: 0.3rem; }
.hints { display: flex; flex-direction: column; gap: 0.4rem; align-items: flex-start; }
.hint { font-size: 0.82rem; line-height: 1.5; background: rgb(228 176 74 / 0.14); border-left: 3px solid var(--amber); border-radius: 0 7px 7px 0; padding: 0.45rem 0.65rem; }
.hint code { background: rgb(60 50 20 / 0.12); }
.banner { border-radius: 8px; padding: 0.7rem 0.8rem; font-size: 0.86rem; font-weight: 600; display: flex; flex-direction: column; gap: 0.55rem; }
.banner-pass { background: rgb(61 122 79 / 0.12); border: 1px solid var(--pass); color: var(--pass); }
.banner-fail { background: rgb(178 58 44 / 0.1); border: 1px solid var(--fail); color: var(--fail); }
.done-mark { color: var(--pass); font-weight: 700; }
.btn-reset-code { align-self: flex-start; font-size: 0.68rem; }
.btn-hint { font-size: 0.72rem; border: 1px dashed var(--panel-edge); }

/* ---------- modals ---------- */

.overlay { position: fixed; inset: 0; background: rgb(40 35 20 / 0.45); display: flex; align-items: center; justify-content: center; padding: 1rem; z-index: 10; }
.modal { background: var(--panel); border: 1px solid var(--panel-edge); border-radius: 12px; box-shadow: 0 20px 60px rgb(0 0 0 / 0.3); max-width: 860px; width: 100%; max-height: 88vh; overflow-y: auto; padding: 1rem 1.2rem 1.2rem; }
.modal-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 0.8rem; }
.modal-head h2 { font-size: 1.1rem; letter-spacing: 0.02em; }
.level-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 0.6rem; }
.level-card { position: relative; display: flex; flex-direction: column; align-items: flex-start; gap: 0.25rem; text-align: left; background: linear-gradient(#faf7ee, #eee9da); border: 1px solid var(--panel-edge); border-radius: 9px; padding: 0.7rem 0.8rem; box-shadow: 0 2px 0 var(--panel-edge); transition: transform 80ms; }
.level-card:hover { transform: translateY(-2px); }
.level-card.current { border-color: var(--olivetti); box-shadow: 0 2px 0 var(--olivetti); }
.level-card .level-num { font-family: var(--mono); font-size: 0.7rem; font-weight: 700; color: var(--olivetti); letter-spacing: 0.1em; }
.level-card .level-name { font-weight: 600; font-size: 0.85rem; }
.level-card .level-desc { font-size: 0.72rem; color: var(--ink-soft); }
.level-card .done-mark { position: absolute; top: 0.55rem; right: 0.7rem; }
.level-card.done { background: linear-gradient(#f2f7ee, #e4ecdc); }
.sandbox-card { border-style: dashed; }
.help-body { font-size: 0.86rem; line-height: 1.55; }
.help-body h3 { font-size: 0.66rem; font-weight: 700; letter-spacing: 0.26em; text-transform: uppercase; color: var(--olivetti); margin: 1rem 0 0.4rem; }
.help-body p { margin-bottom: 0.5rem; }
.help-body table { border-collapse: collapse; width: 100%; font-size: 0.8rem; }
.help-body th, .help-body td { text-align: left; padding: 0.3rem 0.5rem; border-bottom: 1px solid rgb(60 50 20 / 0.12); }
.help-body th { font-size: 0.62rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--ink-soft); }
.intro-foot { display: flex; justify-content: flex-end; margin-top: 1rem; }

/* ---------- workbench layout ---------- */

.workbench {
  flex: 1; display: grid;
  grid-template-columns: minmax(250px, 330px) minmax(440px, 1fr) minmax(300px, 380px);
  gap: 0.9rem; padding: 0.9rem 1.2rem 1.2rem; align-items: start;
  max-width: 1750px; width: 100%; margin: 0 auto;
}
.col-main, .col-inspect { display: flex; flex-direction: column; gap: 0.9rem; }
.toolbar { display: flex; align-items: center; gap: 0.4rem; flex-wrap: wrap; }
.speed { display: flex; align-items: center; gap: 0.4rem; font-size: 0.62rem; font-weight: 700; letter-spacing: 0.18em; text-transform: uppercase; color: var(--ink-soft); margin-left: 0.3rem; }
.speed input { width: 84px; accent-color: var(--olivetti); }

/* ---------- screen inset (shared) ---------- */

.netscreen { position: relative; background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 8px; box-shadow: inset 0 2px 10px rgb(0 0 0 / 0.55); overflow: hidden; }
.netscreen::after { content: ''; position: absolute; inset: 0; background: repeating-linear-gradient(rgb(0 0 0 / 0.09) 0 1px, transparent 1px 3px); pointer-events: none; border-radius: 6px; }

/* ---------- the automaton (signature element) ---------- */

.aut-host { min-height: 150px; padding: 0.3rem; transition: opacity 150ms; }
.aut-host.faded { opacity: 0.25; }
.aut-wrap { position: relative; }
.aut-title { position: absolute; top: 4px; left: 8px; z-index: 2; font-family: var(--mono); font-size: 0.58rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--phosphor-dim); }
.aut-svg svg.aut { display: block; width: 100%; height: auto; max-height: 320px; }

.aut-edge { fill: none; stroke: var(--phosphor-dim); stroke-width: 1.1; stroke-opacity: 0.7; }
.aut-edge-back { stroke-dasharray: 3 2; stroke-opacity: 0.55; }
.aut-label text { font-family: var(--mono); font-size: 10px; fill: var(--phosphor-soft); paint-order: stroke; stroke: var(--screen); stroke-width: 3px; stroke-linejoin: round; }
.aut-start-arrow { fill: none; stroke: var(--phosphor-dim); stroke-width: 1.1; }

.aut-state { fill: rgb(147 232 187 / 0.06); stroke: var(--phosphor-dim); stroke-width: 1.4; transition: fill 120ms, stroke 120ms; }
.aut-ring { fill: none; stroke: var(--phosphor-dim); stroke-width: 1.1; }
.aut-state-label { font-family: var(--mono); font-size: 10px; fill: var(--phosphor-dim); }
.aut-node.active .aut-state { fill: var(--phosphor); stroke: var(--phosphor-soft); filter: drop-shadow(0 0 5px var(--phosphor)); }
.aut-node.active .aut-state-label { fill: var(--screen); font-weight: 700; }
.aut-node.dying .aut-state { fill: rgb(178 58 44 / 0.5); stroke: var(--fail); animation: aut-die 360ms ease-out; }
.aut-node.accept-lit .aut-state { fill: var(--amber); stroke: #fff; filter: drop-shadow(0 0 8px var(--amber)); }
.aut-node.accept-lit .aut-ring { stroke: var(--amber); }

@keyframes aut-die { 0% { fill: var(--fail); } 100% { fill: rgb(147 232 187 / 0.06); } }

/* ---------- the tape ---------- */

.tape-host { padding: 0.5rem 0.6rem; }
.tape { display: flex; flex-wrap: wrap; gap: 3px; font-family: var(--mono); }
.tape-empty { color: var(--phosphor-dim); font-family: var(--mono); font-size: 1rem; }
.tape-cell {
  position: relative; min-width: 1.3em; height: 1.7em; display: inline-flex; align-items: center; justify-content: center;
  color: var(--phosphor); background: rgb(147 232 187 / 0.05); border: 1px solid rgb(147 232 187 / 0.14);
  border-radius: 3px; font-size: 0.9rem; transition: background 100ms, color 100ms, border-color 100ms;
}
.tape-cell.tape-end { color: var(--phosphor-dim); }
.tape-cell.consumed { border-color: rgb(147 232 187 / 0.4); }
.tape-cell.cursor { border-color: var(--amber); box-shadow: 0 0 0 2px rgb(228 176 74 / 0.4); color: var(--phosphor-soft); }
.tape-cell.cursor::after { content: '▾'; position: absolute; top: -0.85em; left: 50%; transform: translateX(-50%); color: var(--amber); font-size: 0.7rem; }
.tape-cell.matched { background: rgb(228 176 74 / 0.28); border-color: var(--amber); color: #fff; }
.tape-cell.dead { background: rgb(178 58 44 / 0.55); border-color: var(--fail); animation: aut-die 300ms ease-out; }
.tape-cell.restart { border-color: var(--phosphor-soft); }
.tape-cell.cap-0 { box-shadow: inset 0 -3px 0 var(--cap-0); }
.tape-cell.cap-1 { box-shadow: inset 0 -3px 0 var(--cap-1); }
.tape-cell.cap-2 { box-shadow: inset 0 -3px 0 var(--cap-2); }
.tape-cell.cap-3 { box-shadow: inset 0 -3px 0 var(--cap-3); }
.tape-cell.cap-4 { box-shadow: inset 0 -3px 0 var(--cap-4); }
.tape-cell.cap-5 { box-shadow: inset 0 -3px 0 var(--cap-5); }

/* ---------- regex bar ---------- */

.rx-editor { display: flex; flex-direction: column; gap: 0.5rem; }
.rx-field { display: flex; align-items: center; gap: 0.3rem; background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 8px; box-shadow: inset 0 2px 10px rgb(0 0 0 / 0.55); padding: 0.4rem 0.6rem; }
.rx-slash { color: var(--olivetti); font-family: var(--mono); font-size: 1.1rem; font-weight: 700; }
.rx-pattern, .rx-input { flex: 1; background: transparent; border: 0; color: var(--phosphor); caret-color: var(--phosphor-soft); font-family: var(--mono); font-size: 0.95rem; text-shadow: 0 0 6px rgb(147 232 187 / 0.25); }
.rx-pattern:focus, .rx-input:focus { outline: none; }
.rx-pattern.has-error { color: #f0b8a0; }
.rx-tag { font-family: var(--mono); font-size: 0.6rem; letter-spacing: 0.14em; color: var(--phosphor-dim); }
.rx-input { font-size: 0.88rem; }
.rx-squiggle { font-family: var(--mono); font-size: 0.75rem; border-left: 3px solid var(--fail); background: rgb(178 58 44 / 0.08); border-radius: 0 6px 6px 0; padding: 0.4rem 0.6rem; }
.rx-echo { color: var(--ink-soft); white-space: pre; overflow-x: auto; margin-bottom: 0.2rem; }
.rx-echo { color: var(--fail); }
.rx-errmsg { color: var(--fail); font-weight: 600; }

.status-line { font-size: 0.78rem; color: var(--ink-soft); min-height: 1.3em; padding-top: 0.5rem; }
.status-line[data-kind="err"] { color: var(--fail); font-weight: 600; }
.status-line[data-kind="ok"] { color: var(--pass); font-weight: 600; }
.status-line[data-kind="run"] { color: var(--ink); }

/* ---------- match inspector ---------- */

.insp-out { margin-bottom: 0.45rem; }
.chip-out { display: inline-block; font-family: var(--mono); font-size: 0.66rem; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; border-radius: 5px; padding: 0.15rem 0.55rem; }
.chip-idle { background: var(--chassis-deep); color: var(--ink-soft); }
.chip-match { background: rgb(61 122 79 / 0.2); color: var(--pass); border: 1px solid var(--pass); }
.chip-nomatch { background: rgb(124 118 99 / 0.15); color: var(--ink-soft); border: 1px solid var(--panel-edge); }
.chip-budget { background: rgb(178 58 44 / 0.15); color: var(--fail); border: 1px solid var(--fail); }
.net-screenbox { background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 7px; box-shadow: inset 0 2px 6px rgb(0 0 0 / 0.5); padding: 0.45rem 0.55rem; overflow-x: auto; min-height: 2.4em; }
.net-tbl { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: 0.74rem; color: var(--phosphor); }
.net-tbl td { padding: 0.16rem 0.5rem 0.16rem 0; white-space: nowrap; }
.net-tbl td.k, .net-tbl td.cap-key { color: var(--phosphor-dim); }
.cap-tbl { margin-top: 0.4rem; border-top: 1px solid rgb(147 232 187 / 0.15); padding-top: 0.3rem; }
.cap-swatch { display: inline-block; width: 9px; height: 9px; border-radius: 2px; margin-right: 0.35rem; vertical-align: middle; }
.cap-swatch.cap-0 { background: var(--cap-0); } .cap-swatch.cap-1 { background: var(--cap-1); }
.cap-swatch.cap-2 { background: var(--cap-2); } .cap-swatch.cap-3 { background: var(--cap-3); }
.cap-swatch.cap-4 { background: var(--cap-4); } .cap-swatch.cap-5 { background: var(--cap-5); }
.tbl-empty { color: var(--phosphor-dim); font-family: var(--mono); font-size: 0.75rem; }

/* ---------- cases panel ---------- */

.cases { display: grid; grid-template-columns: 1fr 1fr; gap: 0.5rem; }
.case-col { display: flex; flex-direction: column; gap: 0.25rem; }
.case-head { font-size: 0.58rem; font-weight: 700; letter-spacing: 0.14em; text-transform: uppercase; margin-bottom: 0.15rem; }
.case-col.must .case-head { color: var(--pass); }
.case-col.mustnot .case-head { color: var(--fail); }
.case-row { display: flex; justify-content: space-between; align-items: center; gap: 0.3rem; font-family: var(--mono); font-size: 0.74rem; background: var(--screen); color: var(--phosphor); border: 1px solid var(--screen-edge); border-radius: 5px; padding: 0.2rem 0.4rem; text-align: left; }
.case-row:hover { border-color: var(--phosphor-dim); }
.case-str { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.case-row.ok { border-color: var(--pass); }
.case-row.ok .case-mark { color: var(--pass); }
.case-row.bad { border-color: var(--fail); background: rgb(178 58 44 / 0.15); }
.case-row.bad .case-mark { color: var(--fail); }

/* ---------- event log tape ---------- */

.evt-tape { background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 7px; box-shadow: inset 0 2px 6px rgb(0 0 0 / 0.5); height: 200px; overflow-y: auto; font-family: var(--mono); font-size: 0.7rem; padding: 0.35rem 0.45rem; }
.evt-row { display: flex; align-items: baseline; gap: 0.4rem; padding: 0.05rem 0.15rem; color: var(--phosphor); white-space: nowrap; border-radius: 3px; }
.evt-time { color: var(--phosphor-dim); flex: 0 0 2.6em; text-align: right; }
.evt-lane { color: var(--amber); flex: 0 0 auto; font-size: 0.6rem; }
.evt-consume { color: var(--phosphor-soft); }
.evt-drop { color: #e88a7a; }
.evt-back { color: var(--amber); }
.evt-cap { color: var(--cap-0); }
.evt-look { color: var(--cap-2); }
.evt-cand { color: var(--phosphor-dim); }
.evt-pass { color: var(--phosphor); font-weight: 700; }
.evt-cmd { color: var(--phosphor-dim); }

/* ---------- responsive ---------- */

@media (max-width: 1240px) {
  .workbench { grid-template-columns: minmax(240px, 300px) 1fr; }
  .col-inspect { grid-column: 1 / -1; flex-direction: row; flex-wrap: wrap; }
  .col-inspect .card { flex: 1 1 300px; }
}
@media (max-width: 800px) {
  .workbench { grid-template-columns: 1fr; padding: 0.7rem; }
  .col-inspect { flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}