:root {
  --bg-body: #171b34;
  --text-main: #eef3ff;
  --panel-bg: #1d2347;
  --panel-border: #2f5fb8;
  --info-color: #c7d3ff;
  --input-bg: #10152d;
  --input-text: #eef3ff;
  --input-border: #2f5fb8;
  --input-focus: #4b8dff;
  --button-bg: #27315f;
  --button-bg-hover: #34427d;
  --button-text: #f4f7ff;
  --output-bg: #0c1125;
  --zebra-odd: rgba(255, 255, 255, 0.04);
  --zebra-even: rgba(255, 255, 255, 0.08);
  --scope-color: #c7d3ff;
  --num-color: #c7d3ff;
  --expr-color: var(--input-text);
  --reason-color: #c7d3ff;
  --small-color: #c7d3ff;
  --error-color: #ffb4b4;
}

body.light-theme {
  --bg-body: #f4f1e8;
  --text-main: #222222;
  --panel-bg: #fffdf8;
  --panel-border: #cdbf9f;
  --info-color: #5f5547;
  --input-bg: #fffefb;
  --input-text: #222222;
  --input-border: #bcae8b;
  --input-focus: #90784d;
  --button-bg: #efe6d3;
  --button-bg-hover: #e2d6bf;
  --button-text: #2d271f;
  --output-bg: #fffef9;
  --zebra-odd: rgba(140, 120, 90, 0.06);
  --zebra-even: rgba(140, 120, 90, 0.12);
  --scope-color: #5f5547;
  --num-color: #5f5547;
  --expr-color: #222222;
  --reason-color: #5f5547;
  --small-color: #5f5547;
  --error-color: #a33a2b;
}

body {
  margin: 0;
  font-family: "Malgun Gothic", "Apple SD Gothic Neo", sans-serif;
  background: var(--bg-body);
  color: var(--text-main);
  transition: background-color 0.2s ease, color 0.2s ease;
}

.container {
  max-width: 1000px;
  margin: 30px auto;
  padding: 0 16px;
}

.panel {
  background: var(--panel-bg);
  transition: background-color 0.2s ease, border-color 0.2s ease;
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
}

.panel h1,
.panel h2 {
  margin-top: 0;
}

.info {
  color: var(--info-color);
  line-height: 1.7;
  white-space: pre-wrap;
}

label {
  display: block;
  font-weight: bold;
  margin-bottom: 8px;
  margin-top: 12px;
}

textarea,
input[type="text"] {
  width: 100%;
  box-sizing: border-box;
  background: var(--input-bg);
  color: var(--input-text);
  border: 1px solid var(--input-border);
  border-radius: 8px;
  padding: 12px;
  font-size: 16px;
  outline: none;
}

textarea {
  min-height: 120px;
  resize: vertical;
}

textarea:focus,
input[type="text"]:focus {
  border-color: var(--input-focus);
}

.symbol-buttons {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 14px;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 10px;
}

.panel-header h1 {
  margin: 0;
}

.action-buttons {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 14px;
  align-items: center;
}

.action-spacer {
  margin-left: auto;
}

button {
  background: var(--button-bg);
  color: var(--button-text);
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 15px;
  cursor: pointer;
}

button:hover {
  background: var(--button-bg-hover);
}

.output {
  background: var(--output-bg);
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
  border: 1px solid var(--input-border);
  border-radius: 8px;
  padding: 12px;
  min-height: 180px;
  font-family: Consolas, "Courier New", monospace;
  line-height: 1.6;
  overflow-x: auto;
}

.output-footer {
  display: flex;
  width: 100%;
  justify-content: flex-end;
  margin-top: 12px;
}

.output-footer #stripeToggleBtn {
  margin-left: auto;
  flex: 0 0 auto;
}

.plain-result {
  white-space: pre-wrap;
}

.fitch-result {
  white-space: pre-wrap;
  margin-bottom: 10px;
}

.fitch-proof {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.fitch-line {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  column-gap: 12px;
  align-items: stretch;
}

.fitch-proof.zebra-on .fitch-line:nth-child(odd) .fitch-main {
  background: var(--zebra-odd);
  border-radius: 4px;
}

.fitch-proof.zebra-on .fitch-line:nth-child(even) .fitch-main {
  background: var(--zebra-even);
  border-radius: 4px;
}

.fitch-line.premise-divider .fitch-main {
  position: relative;
}

.fitch-line.premise-divider .fitch-main::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 64px;
  border-top: 2px solid var(--scope-color);
}

.fitch-num {
  min-width: 2ch;
  text-align: right;
  color: var(--num-color);
  padding-top: 1px;
}

.fitch-main {
  display: flex;
  align-items: stretch;
  min-height: 1.6em;
  min-width: 0;
}

.fitch-content {
  flex: 1;
  min-width: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) max-content;
  column-gap: 12px;
  align-items: stretch;
  padding: 0 4px 0 0;
  border-radius: 4px;
  box-sizing: border-box;
}

.fitch-formula-body {
  display: flex;
  align-items: center;
  min-height: 1.6em;
  min-width: 0;
  box-sizing: border-box;
}

.fitch-scope {
  position: relative;
  width: 18px;
  min-width: 18px;
  border-left: 2px solid var(--scope-color);
  margin-right: 10px;
  align-self: stretch;
  box-sizing: border-box;
}

.fitch-scope.scope-last {
  width: 4px;
  min-width: 4px;
  margin-right: 2px;
}

.fitch-scope.scope-start,
.fitch-scope.scope-branch-end {
  border-left: none;
}

.fitch-scope.scope-start {
  background-image: linear-gradient(var(--scope-color), var(--scope-color));
  background-repeat: no-repeat;
  background-size: 2px calc(100% - 0.72em);
  background-position: left top 0.72em;
}

.fitch-scope.scope-branch-end::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0.72em;
  border-left: 2px solid var(--scope-color);
}

.fitch-scope.scope-start.scope-branch-end {
  background-size: 2px calc(100% - 1.44em);
}

.fitch-scope.scope-start.scope-branch-end::before {
  content: none;
}

.fitch-scope.scope-open::before {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 64px;
  border-top: 2px solid var(--scope-color);
}

.fitch-scope.scope-close::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 64px;
  border-top: 2px solid var(--scope-color);
}

.fitch-expr {
  white-space: pre;
  color: var(--input-text);
}

.fitch-expr-chip,
.fitch-reason-chip {
  display: inline-flex;
  align-items: center;
  min-height: 1.6em;
  padding: 0 8px;
  border-radius: 4px;
  box-sizing: border-box;
}

.fitch-reason {
  display: flex;
  align-items: center;
  white-space: pre;
  color: var(--reason-color);
  min-height: 1.6em;
  box-sizing: border-box;
}

.signature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.signature-card {
  background: #141a37;
  border: 1px solid #2a4d94;
  border-radius: 10px;
  padding: 12px;
}

.signature-card label {
  margin-top: 0;
  margin-bottom: 6px;
  font-size: 14px;
}

.signature-card input[type="text"] {
  padding: 10px;
  font-size: 15px;
}

.signature-help {
  margin-top: 12px;
  color: var(--small-color);
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
}

.help-box {
  margin-top: 16px;
  background: var(--output-bg);
  border: 1px solid var(--panel-border);
  border-radius: 10px;
  padding: 12px;
  color: var(--info-color);
  font-size: 14px;
  line-height: 1.7;
  white-space: pre-wrap;
}

.small {
  color: var(--small-color);
  font-size: 14px;
  margin-top: 8px;
}

.error {
  color: var(--error-color);
}

.top-layout {
  display: grid;
  grid-template-columns: 330px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}

.example-panel {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
  white-space: pre-line;
  font-size: 14px;
  line-height: 1.6;
  color: var(--info-color);
  box-sizing: border-box;
}

@media (max-width: 900px) {
  .top-layout {
    grid-template-columns: 1fr;
  }
}