:root {
  --bg: #0e1116;
  --bg-elev: #161b22;
  --bg-elev-2: #1c2230;
  --border: #2a313c;
  --text: #e6edf3;
  --text-dim: #8b95a5;
  --accent: #6ea8fe;
  --accent-2: #b58cff;
  --success: #3fb950;
  --danger: #f85149;
  --warn: #d29922;
  --hl-1: rgba(110, 168, 254, 0.35);
  --hl-2: rgba(181, 140, 255, 0.35);
  --hl-3: rgba(63, 185, 80, 0.30);
  --hl-4: rgba(210, 153, 34, 0.30);
  --hl-5: rgba(248, 81, 73, 0.30);
  --shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  --radius: 10px;
  --mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;
}

[data-theme="light"] {
  --bg: #f6f8fa;
  --bg-elev: #ffffff;
  --bg-elev-2: #f0f3f7;
  --border: #d9dee5;
  --text: #1f2328;
  --text-dim: #656d76;
  --accent: #0969da;
  --accent-2: #8250df;
  --success: #1a7f37;
  --danger: #cf222e;
  --warn: #9a6700;
  --hl-1: rgba(9, 105, 218, 0.22);
  --hl-2: rgba(130, 80, 223, 0.22);
  --hl-3: rgba(26, 127, 55, 0.22);
  --hl-4: rgba(154, 103, 0, 0.22);
  --hl-5: rgba(207, 34, 46, 0.22);
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

* { box-sizing: border-box; }

html, body {
  margin: 0; padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 14px;
  min-height: 100vh;
  transition: background 0.2s, color 0.2s;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 10;
}

.brand { display: flex; align-items: center; gap: 14px; }
.logo {
  font-family: var(--mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--accent);
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
}
.brand h1 { margin: 0; font-size: 18px; font-weight: 600; }
.subtitle { margin: 2px 0 0; color: var(--text-dim); font-size: 12px; }

.actions { display: flex; align-items: center; gap: 8px; }

select, .icon-btn {
  background: var(--bg-elev-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 7px 12px;
  cursor: pointer;
  font-size: 13px;
  transition: background 0.15s, border-color 0.15s;
}
select:hover, .icon-btn:hover { border-color: var(--accent); }
.icon-btn { display: inline-flex; align-items: center; justify-content: center; padding: 7px; }
.icon-btn svg { width: 18px; height: 18px; }

.layout {
  display: grid;
  grid-template-columns: 1fr 360px;
  grid-template-rows: auto 1fr auto;
  gap: 16px;
  padding: 16px 24px;
  max-width: 1600px;
  margin: 0 auto;
}

.panel {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  box-shadow: var(--shadow);
}

.regex-panel { grid-column: 1 / 2; }
.test-panel  { grid-column: 1 / 2; }
.sub-panel   { grid-column: 1 / 2; }
.info-panel  { grid-column: 2 / 3; grid-row: 1 / 4; display: flex; flex-direction: column; }

.panel-title {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.regex-input-wrap {
  display: flex;
  align-items: center;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 4px 10px;
  font-family: var(--mono);
  transition: border-color 0.15s;
}
.regex-input-wrap:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(110,168,254,0.15); }
.regex-input-wrap.error { border-color: var(--danger); box-shadow: 0 0 0 3px rgba(248,81,73,0.15); }

.delim { color: var(--accent); font-size: 18px; font-weight: 600; padding: 0 4px; }

#pattern {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text);
  font-family: var(--mono);
  font-size: 15px;
  padding: 8px 4px;
}
#flags {
  width: 70px;
  background: transparent;
  border: none;
  outline: none;
  color: var(--accent-2);
  font-family: var(--mono);
  font-size: 15px;
  padding: 8px 4px;
}

.flag-toggles {
  display: flex; flex-wrap: wrap; gap: 8px;
  margin-top: 10px;
}
.flag-toggles label {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 5px 10px;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  font-size: 12px;
  transition: all 0.15s;
}
.flag-toggles label:hover { border-color: var(--accent); }
.flag-toggles label:has(input:checked) {
  background: rgba(110,168,254,0.12);
  border-color: var(--accent);
}
.flag-toggles input { accent-color: var(--accent); }
.flag-toggles span { font-family: var(--mono); font-weight: 600; color: var(--accent); }
.flag-toggles em { color: var(--text-dim); font-style: normal; }

.error-box {
  margin-top: 10px;
  padding: 8px 12px;
  background: rgba(248, 81, 73, 0.1);
  border: 1px solid var(--danger);
  color: var(--danger);
  border-radius: 6px;
  font-family: var(--mono);
  font-size: 12px;
}

.editor {
  position: relative;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  min-height: 220px;
  overflow: hidden;
}
.editor:focus-within { border-color: var(--accent); }

.highlight, #testString {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 12px 14px;
  font-family: var(--mono);
  font-size: 14px;
  line-height: 1.55;
  white-space: pre-wrap;
  word-wrap: break-word;
  border: none;
  overflow-y: auto;
}
.highlight { color: transparent; pointer-events: none; }
.highlight mark {
  color: inherit;
  border-radius: 3px;
  padding: 1px 0;
}
.highlight mark.m0 { background: var(--hl-1); }
.highlight mark.m1 { background: var(--hl-2); }
.highlight mark.m2 { background: var(--hl-3); }
.highlight mark.m3 { background: var(--hl-4); }
.highlight mark.m4 { background: var(--hl-5); }

#testString {
  background: transparent;
  color: var(--text);
  outline: none;
  resize: vertical;
  min-height: 220px;
  caret-color: var(--accent);
}

.match-count {
  font-size: 11px;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  padding: 3px 8px;
  border-radius: 20px;
  color: var(--text-dim);
  text-transform: none;
  letter-spacing: 0;
}

#replacement {
  width: 100%;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 10px 12px;
  font-family: var(--mono);
  font-size: 14px;
  outline: none;
}
#replacement:focus { border-color: var(--accent); }

.sub-result-label {
  margin-top: 10px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
}
.sub-result {
  margin: 6px 0 0;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font-family: var(--mono);
  font-size: 13px;
  min-height: 50px;
  white-space: pre-wrap;
  word-wrap: break-word;
  color: var(--text);
}

.tabs {
  display: flex;
  gap: 4px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 12px;
}
.tab {
  background: transparent;
  border: none;
  color: var(--text-dim);
  padding: 8px 12px;
  cursor: pointer;
  font-size: 13px;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: color 0.15s;
}
.tab:hover { color: var(--text); }
.tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.tab-content { display: none; flex: 1; overflow-y: auto; max-height: 70vh; }
.tab-content.active { display: block; }

.matches-list { display: flex; flex-direction: column; gap: 8px; }
.match-item {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 6px;
  padding: 8px 10px;
}
.match-header {
  font-size: 11px;
  color: var(--text-dim);
  margin-bottom: 4px;
  display: flex; justify-content: space-between;
}
.match-value {
  font-family: var(--mono);
  font-size: 13px;
  word-break: break-all;
  color: var(--text);
}
.match-groups {
  margin-top: 6px;
  border-top: 1px dashed var(--border);
  padding-top: 6px;
}
.group-row {
  display: flex;
  font-size: 12px;
  font-family: var(--mono);
  padding: 2px 0;
  gap: 8px;
}
.group-row .gname { color: var(--accent-2); min-width: 40px; }
.group-row .gval  { color: var(--text); word-break: break-all; }

.empty {
  text-align: center;
  color: var(--text-dim);
  padding: 30px 10px;
  font-size: 13px;
}

.explanation { font-family: var(--mono); font-size: 13px; line-height: 1.7; }
.exp-token {
  display: flex;
  gap: 10px;
  padding: 4px 0;
  border-bottom: 1px dashed var(--border);
}
.exp-token code {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  padding: 1px 6px;
  border-radius: 4px;
  color: var(--accent);
  min-width: 50px;
  text-align: center;
  font-size: 12px;
}
.exp-token span { color: var(--text-dim); flex: 1; }

.cheat h4 {
  margin: 12px 0 6px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-2);
}
.cheat h4:first-child { margin-top: 0; }
.cheat-row {
  display: flex;
  gap: 10px;
  padding: 3px 0;
  font-size: 12px;
}
.cheat-row code {
  font-family: var(--mono);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  padding: 1px 6px;
  border-radius: 4px;
  color: var(--accent);
  min-width: 70px;
  text-align: center;
}
.cheat-row span { color: var(--text-dim); }

.footer {
  text-align: center;
  padding: 16px;
  color: var(--text-dim);
  font-size: 12px;
  border-top: 1px solid var(--border);
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  align-items: center;
}
.footer a {
  color: var(--accent);
  text-decoration: none;
}
.footer a:hover { text-decoration: underline; }

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .info-panel { grid-column: 1; grid-row: auto; }
}

::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dim); }

.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 13px;
  box-shadow: var(--shadow);
  opacity: 0;
  pointer-events: none;
  transition: all 0.25s;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }