:root {
  --bg: #f4f5f7;
  --panel: #ffffff;
  --fg: #1c2128;
  --muted: #59636e;
  --border: #d0d7de;
  --accent: #0a58a8;
  --accent-fg: #ffffff;
  --input-bg: #ffffff;
  --code-bg: #eef0f3;
  --danger: #b3261e;
  --danger-bg: #fdecea;
  --warn: #7a4b00;
  --warn-bg: #fff3d1;
  --ok: #1a6b32;
  --ok-bg: #e2f5e7;
  --hl: #ffe27a;
  --m0: #bfdcfb;
  --m1: #ffd9a8;
  --g0: #d1242f; --g1: #1a7f37; --g2: #8250df; --g3: #bc4c00; --g4: #0969da; --g5: #bf3989;
  --rr-line: #57606a;
  --rr-term-bg: #e3eefb; --rr-term-bd: #2f6db5;
  --rr-sym-bg: #fbeed3; --rr-sym-bd: #a3670a;
  --rr-anchor-bg: #e9ebee; --rr-anchor-bd: #6e7781;
  --rr-group: #6e7781; --rr-capture: #2f6db5; --rr-look: #8250df;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Noto Sans Mono CJK TC", monospace;
  --sans: system-ui, -apple-system, "PingFang TC", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1216;
    --panel: #171b21;
    --fg: #e6e9ed;
    --muted: #9aa5b1;
    --border: #2f3843;
    --accent: #6cb2ff;
    --accent-fg: #0b1320;
    --input-bg: #0f1216;
    --code-bg: #232a33;
    --danger: #ff8a80;
    --danger-bg: #3a1a18;
    --warn: #ffd27a;
    --warn-bg: #3a2c0c;
    --ok: #6fdc8c;
    --ok-bg: #143221;
    --hl: #6b5a00;
    --m0: #1f4a75;
    --m1: #6b4a12;
    --g0: #ff7b72; --g1: #56d364; --g2: #bc8cff; --g3: #ffa657; --g4: #79c0ff; --g5: #f778ba;
    --rr-line: #9aa5b1;
    --rr-term-bg: #1b2f4a; --rr-term-bd: #6cb2ff;
    --rr-sym-bg: #3a2c12; --rr-sym-bd: #e0a24a;
    --rr-anchor-bg: #2a313a; --rr-anchor-bd: #9aa5b1;
    --rr-group: #9aa5b1; --rr-capture: #6cb2ff; --rr-look: #bc8cff;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--fg);
  font: 15px/1.6 var(--sans);
}
h1, h2, h3 { margin: 0; font-weight: 600; }
h1 { font-size: 18px; }
h2 { font-size: 15px; }
h3 { font-size: 13px; color: var(--muted); font-weight: 600; margin: 16px 0 6px; }
code, pre, textarea, input, select { font-family: var(--mono); }
code { background: var(--code-bg); padding: 0 4px; border-radius: 3px; font-size: 0.92em; }
a { color: var(--accent); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.top {
  display: flex; flex-wrap: wrap; gap: 12px 24px; align-items: center; justify-content: space-between;
  padding: 12px 16px; border-bottom: 1px solid var(--border); background: var(--panel);
}
.top p { margin: 0; color: var(--muted); font-size: 13px; }
.tools { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.tools select { max-width: 100%; }

main { max-width: 1320px; margin: 0 auto; padding: 16px; }
.panel { background: var(--panel); border: 1px solid var(--border); border-radius: 6px; padding: 14px 16px; margin-bottom: 16px; }
.panel > h2 { margin-bottom: 8px; }

button, select {
  font: 14px var(--sans); color: var(--fg); background: var(--panel);
  border: 1px solid var(--border); border-radius: 5px; padding: 6px 10px; min-height: 34px; cursor: pointer;
}
button:hover, select:hover { border-color: var(--muted); }
button.primary { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
input[type="text"], textarea {
  width: 100%; background: var(--input-bg); color: var(--fg); border: 1px solid var(--border);
  border-radius: 5px; padding: 8px 10px; font-size: 14px; line-height: 1.5;
}
textarea { resize: vertical; min-height: 88px; }
label.lbl { display: block; font-size: 13px; color: var(--muted); margin-bottom: 4px; }

.regex-row { display: flex; align-items: center; gap: 6px; }
.regex-row .slash { font: 20px var(--mono); color: var(--muted); }
.regex-row input { font-size: 17px; }
.flags { display: flex; flex-wrap: wrap; gap: 4px 10px; margin: 8px 0 0; padding: 0; border: 0; }
.flags legend { font-size: 13px; color: var(--muted); padding: 0; margin-right: 4px; float: left; line-height: 28px; }
.flags label { display: inline-flex; align-items: center; gap: 4px; font: 14px var(--mono); min-height: 28px; cursor: pointer; }
.flags input { width: 16px; height: 16px; margin: 0; }
.flags .fn { font: 12px var(--sans); color: var(--muted); }

.regexview {
  margin-top: 10px; font: 15px/1.7 var(--mono); white-space: pre-wrap; word-break: break-all;
  background: var(--code-bg); border-radius: 5px; padding: 6px 10px; min-height: 34px;
}
.regexview span.hl { background: var(--hl); border-radius: 2px; }
.viewcap { font-size: 12px; color: var(--muted); margin-top: 4px; }

.err { margin-top: 10px; padding: 8px 12px; border-radius: 5px; background: var(--danger-bg); color: var(--danger); border: 1px solid var(--danger); }
.err pre { margin: 6px 0 0; font-size: 14px; white-space: pre-wrap; word-break: break-all; }
.err .hint { color: var(--fg); font-size: 13px; margin-top: 4px; }
.warn { margin-top: 10px; padding: 8px 12px; border-radius: 5px; background: var(--warn-bg); color: var(--warn); border: 1px solid var(--warn); }
.warn ul { margin: 4px 0 0; padding-left: 20px; }
.warn .lv { font-weight: 700; }
.note { color: var(--muted); font-size: 13px; }
.notice { margin: 8px 0 0; padding: 8px 12px; border-radius: 5px; border: 1px solid var(--warn); background: var(--warn-bg); color: var(--warn); font-size: 14px; }

.grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: 0 16px; align-items: start; }
@media (min-width: 1000px) { .grid { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); } }

.legend { display: flex; flex-wrap: wrap; gap: 4px 14px; font-size: 13px; margin: 0 0 8px; padding: 0; list-style: none; }
.legend li { display: inline-flex; align-items: center; gap: 6px; }
.chip { display: inline-block; width: 22px; height: 14px; border-radius: 3px; border: 1px solid var(--border); }
.chip.m0 { background: var(--m0); } .chip.m1 { background: var(--m1); }
.chip.g { background: var(--panel); border: 0; border-bottom: 3px solid currentColor; height: 14px; border-radius: 0; }
.preview {
  margin: 0; padding: 10px 12px; background: var(--input-bg); border: 1px solid var(--border); border-radius: 5px;
  font: 14px/2 var(--mono); white-space: pre-wrap; word-break: break-word; max-height: 320px; overflow: auto; min-height: 44px;
}
.preview .m0 { background: var(--m0); } .preview .m1 { background: var(--m1); }
.preview .zero { display: inline-block; width: 0; border-left: 2px solid var(--fg); height: 1.1em; vertical-align: text-bottom; }

.tablewrap { overflow-x: auto; border: 1px solid var(--border); border-radius: 5px; max-height: 320px; overflow-y: auto; }
table { border-collapse: collapse; width: 100%; font-size: 13px; }
th, td { text-align: left; padding: 5px 10px; border-bottom: 1px solid var(--border); vertical-align: top; }
th { color: var(--muted); font-weight: 600; background: var(--code-bg); position: sticky; top: 0; }
td.mono { font-family: var(--mono); word-break: break-all; }
tr:last-child td { border-bottom: 0; }
.gtag { display: inline-block; margin: 0 8px 2px 0; }
.gtag b { font-weight: 700; }
.badge { display: inline-block; font-size: 12px; padding: 0 8px; border-radius: 10px; font-weight: 600; }
.badge.pass { background: var(--ok-bg); color: var(--ok); }
.badge.fail { background: var(--danger-bg); color: var(--danger); }

.unit { display: grid; grid-template-columns: minmax(0, 1fr); gap: 10px; }
@media (min-width: 560px) { .unit { grid-template-columns: 1fr 1fr; } }
.unit textarea { min-height: 96px; }
.cases { margin: 10px 0 0; padding: 0; list-style: none; font-size: 13px; }
.cases li { display: flex; gap: 8px; align-items: baseline; padding: 3px 0; border-bottom: 1px dashed var(--border); }
.cases li .t { font-family: var(--mono); word-break: break-all; }
.summary { font-size: 13px; margin-top: 8px; }

details.tpl { margin-top: 10px; font-size: 14px; }
details.tpl summary { cursor: pointer; color: var(--accent); }
details.tpl ul { margin: 6px 0 0; padding-left: 20px; color: var(--muted); }

/* 解釋樹 */
.flagex { margin: 0 0 8px; padding: 0; list-style: none; font-size: 13px; color: var(--muted); }
.flagex code { color: var(--fg); }
.tree, .tree ul { list-style: none; margin: 0; padding: 0; }
.tree ul { margin-left: 14px; border-left: 1px solid var(--border); padding-left: 10px; }
.tree li { margin: 2px 0; }
.tree details > summary { list-style: none; cursor: pointer; }
.tree details > summary::-webkit-details-marker { display: none; }
.tree details > summary::before { content: "▸"; display: inline-block; width: 1.1em; color: var(--muted); }
.tree details[open] > summary::before { content: "▾"; }
.tree .leafmark { display: inline-block; width: 1.1em; color: var(--border); }
.row { display: block; padding: 3px 6px; border-radius: 4px; }
.row:hover, .row.active { background: var(--hl); }
.row code { margin-right: 8px; word-break: break-all; }
.row .zh { overflow-wrap: anywhere; }

.scroll { overflow-x: auto; border: 1px solid var(--border); border-radius: 5px; background: var(--input-bg); padding: 4px; }
.railroad { display: block; max-width: none; }
.rr-line { fill: none; stroke: var(--rr-line); stroke-width: 1.6; }
.rr-terminal { fill: var(--rr-term-bg); stroke: var(--rr-term-bd); stroke-width: 1.4; }
.rr-symbol { fill: var(--rr-sym-bg); stroke: var(--rr-sym-bd); stroke-width: 1.4; }
.rr-anchor { fill: var(--rr-anchor-bg); stroke: var(--rr-anchor-bd); stroke-width: 1.2; }
.rr-group { fill: none; stroke: var(--rr-group); stroke-width: 1.3; stroke-dasharray: 6 4; }
.rr-group.rr-capture { stroke: var(--rr-capture); }
.rr-group.rr-look { stroke: var(--rr-look); stroke-dasharray: 2 3; }
.rr-text { font: 13px var(--mono); text-anchor: middle; fill: var(--fg); }
.rr-sub { font: 11px var(--sans); text-anchor: middle; fill: var(--muted); }
.rr-anchor-text { fill: var(--fg); font-size: 12px; }
.rr-label { font: 11.5px var(--sans); text-anchor: middle; fill: var(--muted); }
.rr-glabel { font: 11.5px var(--sans); fill: var(--muted); }
.rr-end { fill: var(--rr-line); }
.rr-end-in { fill: var(--input-bg); }
.rr-arrow { fill: var(--rr-line); }
.rr-node { cursor: default; }
.rr-node:hover .rr-terminal, .rr-node:hover .rr-symbol, .rr-node:hover .rr-anchor { stroke-width: 2.6; }
.rr-groupbox:hover .rr-group { stroke-width: 2.4; }

footer { max-width: 1320px; margin: 0 auto; padding: 0 16px 32px; color: var(--muted); font-size: 13px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
@media (max-width: 520px) {
  main { padding: 12px; }
  .panel { padding: 12px; }
  .regex-row input { font-size: 15px; }
}