:root {
  --ink: #17202a;
  --muted: #3e4c58;
  --paper: #f3efe4;
  --paper-2: #fffdf8;
  --line: #d9d1c3;
  --signal: #dff25a;
  --signal-ink: #1a2208;
  --tree: #101820;
  --tree-ink: #e7f0c8;
  --server: #1c6b45;
  --client: #8a4e10;
  --split: #3f3a78;
  --focus: #17202a;
  --grid: rgba(16, 24, 32, 0.045);
  color-scheme: light;
  font-family: "Segoe UI", system-ui, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #ece7dc;
    --muted: #a8b0b8;
    --paper: #141a21;
    --paper-2: #1c2530;
    --line: #31404e;
    --signal: #dff25a;
    --signal-ink: #1a2208;
    --tree: #0b1016;
    --tree-ink: #e7f0c8;
    --server: #8ed4b0;
    --client: #f0c27a;
    --split: #c9bef5;
    --focus: #dff25a;
    --grid: rgba(236, 231, 220, 0.04);
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

body {
  margin: 0;
  min-height: 100dvh;
  background: var(--paper);
  color: var(--ink);
  font: 17px/1.5 system-ui, "Segoe UI", sans-serif;
}

:focus { outline: none; }

:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.skip {
  position: absolute;
  left: 0.75rem;
  top: 0.75rem;
  transform: translateY(-150%);
  background: var(--signal);
  color: var(--signal-ink);
  padding: 0.4rem 0.7rem;
  border-radius: 8px;
  z-index: 2;
}

.skip:focus { transform: none; }

.top {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.35rem 1.5rem;
  align-items: end;
  padding: 1.15rem 1.4rem 0.85rem;
  border-bottom: 1px solid var(--line);
  background: var(--paper-2);
}

.brand {
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.brand img { border-radius: 8px; display: block; }

.kicker {
  margin: 0;
  font: 600 0.72rem/1.2 ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

h1 {
  margin: 0;
  font-size: 1.7rem;
  line-height: 1.1;
  letter-spacing: -0.03em;
}

.lede {
  margin: 0;
  max-width: 40rem;
  color: var(--muted);
}

.tabs {
  display: flex;
  gap: 0.35rem;
  grid-column: 2;
  grid-row: 1 / span 2;
  align-self: center;
}

.tabs button {
  appearance: none;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  border-radius: 999px;
  min-height: 44px;
  padding: 0 0.95rem;
  font: 600 0.95rem/1 system-ui, "Segoe UI", sans-serif;
  cursor: pointer;
}

.tabs button[aria-selected="true"] {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

main {
  padding: 1.1rem 1.4rem 1.5rem;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 22px 22px;
}

#panel-decide,
#panel-files,
#panel-boundary {
  display: grid;
  grid-template-columns: minmax(16rem, 22rem) minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
}

.stack, .result, .miss {
  min-width: 0;
}

fieldset {
  margin: 0 0 0.85rem;
  padding: 0;
  border: 0;
  display: grid;
  gap: 0.4rem;
}

legend {
  font-weight: 700;
  margin-bottom: 0.35rem;
  padding: 0;
}

.choice {
  display: flex;
  gap: 0.65rem;
  align-items: flex-start;
  border: 1px solid var(--line);
  background: var(--paper-2);
  border-radius: 12px;
  padding: 0.6rem 0.7rem;
  cursor: pointer;
}

.choice input { margin-top: 0.25rem; accent-color: var(--ink); }

.choice:has(input:checked) input { accent-color: var(--signal-ink); }

.choice strong { display: block; font-size: 0.98rem; }

.choice small {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1.35;
}

.choice:has(input:checked) {
  background: var(--signal);
  border-color: #c5d64a;
  color: var(--signal-ink);
}

.choice:has(input:checked) small { color: var(--signal-ink); }

.choice:has(input:focus-visible) {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

button, .back {
  font: 600 0.95rem/1 system-ui, "Segoe UI", sans-serif;
}

#reset, .tree-actions button, .back {
  appearance: none;
  border: 1px solid var(--line);
  background: var(--paper-2);
  color: var(--ink);
  border-radius: 10px;
  min-height: 44px;
  padding: 0 0.85rem;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
}

.tree-actions button {
  background: transparent;
  color: var(--tree-ink);
  border-color: rgba(231, 240, 200, 0.35);
}

.summary {
  margin: 0 0 0.35rem;
  font-size: 1.45rem;
  line-height: 1.15;
  letter-spacing: -0.03em;
  font-weight: 700;
}

.why, .hint, .status, footer p, .example, .files p { margin: 0; }

.why { color: var(--ink); margin-bottom: 0.75rem; }

.notes {
  margin: 0 0 0.8rem;
  padding-left: 1.1rem;
  display: grid;
  gap: 0.35rem;
}

.notes li { padding-left: 0.15rem; }

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 0.9rem;
}

.tags span, .kind {
  font: 600 0.75rem/1 ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.28rem 0.5rem;
  color: var(--muted);
}

.kind[data-kind="pattern"] { color: var(--split); border-color: color-mix(in srgb, var(--split) 45%, var(--line)); }
.kind[data-kind="directive"] { color: var(--client); border-color: color-mix(in srgb, var(--client) 45%, var(--line)); }
.kind[data-kind="suffix"] { color: var(--server); border-color: color-mix(in srgb, var(--server) 45%, var(--line)); }

.tree-card {
  background: var(--tree);
  color: var(--tree-ink);
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid #000;
}

.tree-bar {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  align-items: center;
  padding: 0.55rem 0.7rem 0.55rem 0.95rem;
  border-bottom: 1px solid rgba(231, 240, 200, 0.14);
}

.tree-bar h2 {
  margin: 0;
  font: 600 0.75rem/1 ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.tree-actions { display: flex; gap: 0.35rem; }

.tree {
  margin: 0;
  padding: 0.85rem 1rem 1rem;
  overflow: auto;
  font: 13px/1.55 ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  max-height: min(68vh, 40rem);
}

.tree-line {
  display: flex;
  gap: 1.5rem;
  align-items: baseline;
  white-space: pre;
}

.tree-note { color: #b7c7a1; }

.status { min-height: 1.4rem; margin-top: 0.55rem; color: var(--muted); }

.hint { margin-top: 0.7rem; color: var(--muted); font-size: 0.92rem; }

.search { font-weight: 700; }

input[type="search"] {
  width: 100%;
  margin: 0.4rem 0 0.55rem;
  min-height: 44px;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: var(--paper-2);
  color: var(--ink);
  font: 16px/1.4 system-ui, "Segoe UI", sans-serif;
  padding: 0.4rem 0.7rem;
}

.files {
  list-style: none;
  margin: 0.4rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.55rem;
}

.files li {
  background: var(--paper-2);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.7rem 0.8rem;
}

.file-top {
  display: flex;
  justify-content: space-between;
  gap: 0.6rem;
  align-items: baseline;
  margin-bottom: 0.25rem;
}

.file-top code {
  font: 600 0.95rem/1.3 ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}

.example {
  margin-top: 0.3rem;
  color: var(--muted);
  font: 0.86rem/1.4 ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}

.empty {
  margin-top: 0.8rem;
  padding: 0.9rem 1rem;
  border: 1px dashed var(--line);
  border-radius: 12px;
  background: var(--paper-2);
}

.directive {
  display: inline-block;
  margin: 0.2rem 0 0.7rem;
  padding: 0.35rem 0.6rem;
  border-radius: 8px;
  background: var(--tree);
  color: var(--tree-ink);
  font: 600 0.92rem/1.3 ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}

#verdict[data-verdict="server"] .kicker { color: var(--server); }
#verdict[data-verdict="client"] .kicker { color: var(--client); }
#verdict[data-verdict="split"] .kicker { color: var(--split); }

#verdict h2 {
  margin: 0.15rem 0 0.45rem;
  font-size: 1.6rem;
  letter-spacing: -0.03em;
}

.banner {
  margin: 0 0 1rem;
  padding: 0.75rem 0.9rem;
  border-radius: 12px;
  background: var(--signal);
  color: var(--signal-ink);
}

footer {
  padding: 0 1.4rem 1.4rem;
  color: var(--muted);
  font-size: 0.92rem;
}

.miss {
  max-width: 36rem;
  padding: 3rem 1.4rem;
}

.miss h1 { font-size: 2rem; margin: 0.3rem 0 0.6rem; }

.miss p { color: var(--muted); }

.miss .back { margin-top: 1rem; }

@media (max-width: 800px) {
  .tree-line { display: block; white-space: pre; }
  .tree-note {
    display: block;
    margin: 0 0 0.2rem 1.25rem;
    white-space: normal;
  }
}

@media (max-width: 800px) {
  .top { grid-template-columns: 1fr; padding: 1rem; }
  .tabs { grid-column: 1; grid-row: auto; margin-top: 0.35rem; }
  main, footer { padding-left: 1rem; padding-right: 1rem; }
  #panel-decide,
  #panel-files,
  #panel-boundary { grid-template-columns: 1fr; }
  .summary { font-size: 1.3rem; }
  .tabs button { flex: 1; }
}

@media (max-width: 380px) {
  .tree-bar { flex-wrap: wrap; }
  h1 { font-size: 1.45rem; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; scroll-behavior: auto !important; }
}