:root {
  --bg-primary: #fafafa;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f0f0f0;
  --border-color: #e0e0e0;
  --text-primary: #333;
  --text-secondary: #666;
  --text-muted: #999;
  --accent: #5c6bc0;
  --accent-light: #e8eaf6;
  --success: #43a047;
  --success-light: #e8f5e9;
  --warning: #f9a825;
  --warning-light: #fff8e1;
  --conflict: #e53935;
  --conflict-light: #ffebee;
  --highlight: #42a5f5;
  --highlight-light: #e3f2fd;
  --branch-diff: #00897b;
  --branch-diff-light: #e0f2f1;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Meiryo", system-ui, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 20px;
}

h1 {
  text-align: center;
  margin-bottom: 8px;
  color: var(--accent);
  font-weight: 600;
  font-size: 1.5rem;
}

.subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: 32px;
}

/* Section */
.section {
  margin-bottom: 24px;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.section-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
}

/* Input Area */
#cipherInput {
  width: 100%;
  min-height: 100px;
  padding: 16px;
  font-family: 'Consolas', 'Monaco', 'Menlo', monospace;
  font-size: 16px;
  line-height: 1.8;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-primary);
  resize: vertical;
}

#cipherInput:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

#cipherInput::placeholder {
  color: var(--text-muted);
}

/* Mapping Table */
.mapping-section {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 20px;
}

.mapping-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 8px;
}

.mapping-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  background: var(--bg-tertiary);
  border-radius: 6px;
  transition: background 0.15s;
}

.mapping-item:hover,
.mapping-item.highlighted {
  background: var(--highlight-light);
}

.mapping-item.conflict {
  background: var(--conflict-light);
}

.cipher-letter {
  font-family: 'Consolas', 'Monaco', 'Menlo', monospace;
  font-size: 16px;
  font-weight: 600;
  color: var(--accent);
  width: 20px;
  text-align: center;
}

.mapping-inputs {
  display: flex;
  gap: 4px;
  flex: 1;
}

.mapping-input {
  width: 100%;
  padding: 4px 6px;
  font-family: 'Consolas', 'Monaco', 'Menlo', monospace;
  font-size: 13px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  color: var(--text-primary);
}

.mapping-input:focus {
  outline: none;
  border-color: var(--accent);
}

.mapping-input::placeholder {
  color: var(--text-muted);
  font-size: 11px;
}

.mapping-input.fixed {
  flex: 0 0 32px;
}

.mapping-input.candidates {
  flex: 1;
}

/* Unused Letters Section */
.unused-section {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border-color);
}

.unused-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.unused-letters {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

.unused-letter {
  padding: 2px 6px;
  font-family: 'Consolas', 'Monaco', 'Menlo', monospace;
  font-size: 12px;
  background: var(--bg-tertiary);
  border-radius: 4px;
  color: var(--text-secondary);
}

.unused-letter.candidate-only {
  background: var(--warning-light);
  color: var(--warning);
}

/* Branch Results */
.branch-count {
  font-weight: normal;
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Export Buttons */
.export-buttons {
  display: flex;
  gap: 8px;
  margin-left: auto;
}

.export-btn {
  padding: 6px 12px;
  font-size: 0.75rem;
  font-weight: 500;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.15s, opacity 0.15s;
}

.export-btn:hover {
  background: #4a5ab8;
}

.export-btn:disabled {
  opacity: 0.7;
  cursor: default;
}

.export-btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.export-btn-secondary:hover {
  background: var(--border-color);
}

.branch-cards {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.branch-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 16px;
}

.branch-label {
  font-family: 'Consolas', 'Monaco', 'Menlo', monospace;
  font-size: 12px;
  color: var(--branch-diff);
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.branch-label.base-only {
  color: var(--text-muted);
}

.decoded-text {
  font-family: 'Consolas', 'Monaco', 'Menlo', monospace;
  font-size: 16px;
  line-height: 2;
  white-space: pre-wrap;
  word-break: break-all;
}

.decoded-char {
  transition: background 0.15s;
  border-radius: 2px;
}

.decoded-char.undecoded {
  color: var(--text-muted);
}

.decoded-char.undecoded-raw {
  color: var(--accent);
  font-weight: 600;
}

.decoded-char.decoded {
  color: var(--success);
}

.decoded-char.original-plain {
  color: var(--text-primary);
}

.decoded-char.branch-specific {
  background: var(--branch-diff-light);
  color: var(--branch-diff);
}

.decoded-char.highlighted {
  background: var(--highlight-light);
}

.decoded-char.conflict {
  text-decoration: underline wavy var(--conflict);
}

/* No branches message */
.no-branches {
  padding: 32px;
  text-align: center;
  color: var(--text-muted);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 0.875rem;
}

/* Footer */
.footer {
  text-align: center;
  padding: 16px 20px;
  color: var(--text-muted);
  font-size: 0.875rem;
}

.footer a {
  color: var(--accent);
  text-decoration: none;
}

.footer a:hover {
  text-decoration: underline;
}