* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(135deg, #1a472a 0%, #2d5a3f 100%);
  min-height: 100vh;
  margin: 0;
  padding: 0;
  color: #333;
}

/* Tool header for continuity across tools */
.tool-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(26, 71, 42, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.tool-nav {
  width: 100%;
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 16px;
}

.tool-nav__link {
  text-decoration: none;
  color: #fff;
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.tool-nav__link:hover {
  color: #d7f3df;
}

.container {
  max-width: 600px;
  margin: 0 auto;
  padding: 16px;
}

h1 {
  color: #fff;
  text-align: center;
  margin: 0 0 24px 0;
  font-size: 1.75rem;
}

h1 span {
  display: inline-block;
}

.card {
  background: #fff;
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 16px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.card h2 {
  margin: 0 0 16px 0;
  font-size: 1.1rem;
  color: #1a472a;
  display: flex;
  align-items: center;
  gap: 8px;
}

.card-description {
  margin: 0 0 12px;
  color: #666;
  font-size: 0.9rem;
}

.input-row {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
}

input[type="text"] {
  flex: 1;
  padding: 12px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 16px;
  transition: border-color 0.2s;
}

input[type="text"]:focus {
  outline: none;
  border-color: #1a472a;
}

button {
  padding: 12px 20px;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  touch-action: manipulation;
}

.btn-add {
  background: #1a472a;
  color: #fff;
}

.btn-add:hover {
  background: #2d5a3f;
}

.btn-add:active {
  transform: scale(0.98);
}

.btn-generate {
  width: 100%;
  padding: 16px;
  background: #c41e3a;
  color: #fff;
  font-size: 1.1rem;
}

.btn-generate:hover {
  background: #a01830;
}

.btn-generate:disabled {
  background: #ccc;
  cursor: not-allowed;
}

.list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: #f0f7f2;
  border: 1px solid #c8e0cc;
  padding: 8px 12px;
  border-radius: 20px;
  font-size: 0.95rem;
}

.tag-remove {
  background: none;
  border: none;
  color: #999;
  cursor: pointer;
  padding: 0;
  font-size: 1.2rem;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.tag-remove:hover {
  color: #c41e3a;
}

.rule-tag {
  background: #fff5f5;
  border-color: #f0c0c0;
}

.forced-tag {
  background: #f0f5ff;
  border-color: #c0d0f0;
}

.rule-row {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
}

select {
  flex: 1;
  min-width: 100px;
  padding: 12px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 16px;
  background: #fff;
  cursor: pointer;
}

select:focus {
  outline: none;
  border-color: #1a472a;
}

.rule-arrow {
  font-weight: bold;
  color: #666;
}

.empty-state {
  color: #999;
  font-style: italic;
  padding: 8px 0;
}

.results-card {
  background: linear-gradient(135deg, #fdf6e3 0%, #fff9e6 100%);
  border: 2px solid #f0d060;
}

.results-card h2 {
  color: #8b6914;
}

.result-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  background: #fff;
  border-radius: 8px;
  margin-bottom: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.result-item:last-child {
  margin-bottom: 0;
}

.result-giver {
  font-weight: 600;
  color: #1a472a;
}

.result-arrow {
  color: #c41e3a;
  font-size: 1.2rem;
}

.result-receiver {
  color: #333;
}

.error-message {
  background: #fff0f0;
  border: 1px solid #ffcccc;
  color: #c41e3a;
  padding: 12px;
  border-radius: 8px;
  margin-top: 12px;
}

.btn-reset {
  width: 100%;
  padding: 12px;
  background: #666;
  color: #fff;
  margin-top: 12px;
}

.btn-reset:hover {
  background: #555;
}

.btn-copy {
  width: 100%;
  padding: 12px;
  background: #4a7c59;
  color: #fff;
  margin-top: 8px;
}

.btn-copy:hover {
  background: #3d6649;
}

.btn-copy.copied {
  background: #2d5a3f;
}

.permutation-count {
  margin-bottom: 12px;
  font-size: 0.9rem;
}

.results-note {
  margin: 12px 0 0;
  color: #666;
  font-size: 0.85rem;
  text-align: center;
}

.seed-banner {
  margin-bottom: 12px;
  padding: 8px 12px;
  background: #e8f5e9;
  border-radius: 6px;
  font-size: 0.85rem;
  color: #2e7d32;
}

.muted-message {
  color: #999;
}

@media (max-width: 400px) {
  .rule-row {
    flex-direction: column;
  }

  .rule-row select {
    width: 100%;
  }

  .rule-row .btn-add {
    width: 100%;
  }

  .rule-arrow {
    display: none;
  }
}