:root {
  --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
  --card-bg: rgba(30, 41, 59, 0.7);
  --border: rgba(255, 255, 255, 0.1);
  --text: #f8fafc;
  --text-muted: #94a3b8;
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --success: #10b981;
  --error: #ef4444;
}

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

body {
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg-gradient);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 2rem;
}

/* --- Two-column layout --- */
.layout {
  display: flex;
  gap: 2.5rem;
  align-items: center;
  max-width: 960px;
}

/* Left: info panel */
.info-panel {
  flex: 1;
  max-width: 375px;
  padding-top: 1rem;
}

.info-panel h1 {
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 0.75rem;
  background: linear-gradient(to right, #a5b4fc, #6366f1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.info-desc {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.6;
  margin-bottom: 0.5rem;
  text-wrap: balance;
}

.info-note {
  color: var(--text-muted);
  font-size: 0.8rem;
  opacity: 0.6;
  font-style: italic;
}

/* Right: checker panel */
.checker-panel {
  flex: 1;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* Input card */
.input-card {
  background: var(--card-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 2rem 2.5rem;
  width: 100%;
  box-shadow: 0 15px 30px -10px rgba(0, 0, 0, 0.4);
}

.input-row {
  display: flex;
  gap: 0.75rem;
}

.input-row input {
  flex: 1;
}

.input-row button {
  flex-shrink: 0;
  width: auto;
  padding: 0.75rem 1.5rem;
  margin-top: 0;
}

label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
  color: var(--text);
}

input[type="text"] {
  width: 100%;
  padding: 0.75rem 1rem;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text);
  font-family: inherit;
  font-size: 1rem;
  transition: all 0.2s ease;
}

input[type="text"]:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

button {
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 12px;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

button:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
}

button:active {
  transform: translateY(0);
}

/* --- Result card --- */
.result-card {
  width: 100%;
  opacity: 0;
  transition: opacity 0.35s ease;
}

.result-card.visible {
  opacity: 1;
}

.result-inner {
  border-radius: 16px;
  padding: 1.5rem;
  text-align: center;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.result-card.success .result-inner {
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.15), rgba(6, 78, 59, 0.25));
  border: 1px solid rgba(16, 185, 129, 0.3);
  box-shadow: 0 20px 60px -15px rgba(16, 185, 129, 0.2);
}

.result-card.error .result-inner {
  background: linear-gradient(135deg, rgba(239, 68, 68, 0.12), rgba(127, 29, 29, 0.2));
  border: 1px solid rgba(239, 68, 68, 0.25);
  box-shadow: 0 20px 60px -15px rgba(239, 68, 68, 0.15);
}

.result-icon {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  line-height: 1;
}

.result-card.success .result-icon {
  color: var(--success);
}

.result-card.error .result-icon {
  color: var(--error);
}

.result-word {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
}

.result-msg {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.rae-link {
  display: inline-block;
  margin-top: 0.5rem;
  color: #a5b4fc;
  font-size: 0.85rem;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.2s ease;
}

.rae-link:hover {
  color: #c7d2fe;
}

/* Gear button */
.gear-btn {
  position: fixed;
  top: 1.25rem;
  right: 1.25rem;
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: 50%;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 1.25rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
  z-index: 100;
}

.gear-btn:hover {
  color: var(--text);
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--primary);
  transform: rotate(45deg);
}

/* Dialog */
.settings-dialog {
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 2rem;
  width: 90%;
  max-width: 420px;
  color: var(--text);
  box-shadow: 0 25px 60px -12px rgba(0, 0, 0, 0.6);
}

.settings-dialog::backdrop {
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.modal-title {
  font-weight: 700;
  font-size: 1.1rem;
}

.modal-close {
  width: 32px;
  height: 32px;
  padding: 0;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.modal-close:hover {
  background: rgba(239, 68, 68, 0.15);
  color: var(--error);
  transform: none;
}

.settings-dialog .form-group {
  margin-bottom: 0;
}

/* Responsive: stack on small screens */
@media (max-width: 1024px) {
  .layout {
    flex-direction: column;
    gap: 1.5rem;
    align-items: center;
  }

  .info-panel {
    max-width: 500px;
    text-align: center;
  }

  .info-panel h1 {
    font-size: 2rem;
  }
}