:root {
  --bg: #0f172a;
  --card: #1e293b;
  --border: #334155;
  --text: #e2e8f0;
  --primary: #38bdf8;
  --success: #4ade80;
  --danger: #f87171;
  --kbd-bg: #2d3b4f;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1rem;
}

.container {
  max-width: 820px;
  width: 100%;
  background: var(--card);
  border-radius: 28px;
  padding: 2rem 1.8rem;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.6);
  border: 1px solid var(--border);
}

h1 {
  font-size: 1.9rem;
  font-weight: 600;
  text-align: center;
  margin-bottom: 0.5rem;
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subtitle {
  text-align: center;
  color: #94a3b8;
  font-size: 0.95rem;
  margin-bottom: 1.8rem;
}

.question-box {
  background: #0f172a;
  border-radius: 18px;
  padding: 1.8rem 1.5rem;
  margin-bottom: 1.5rem;
  border-left: 6px solid var(--primary);
  min-height: 100px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 1.6rem;
  font-weight: 500;
  line-height: 1.5;
}

.question-box .q-label {
  font-size: 1rem;
  font-weight: 400;
  color: #94a3b8;
  margin-right: 0.5rem;
}

.input-area {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

.input-row {
  display: flex;
  gap: 0.8rem;
  flex-wrap: wrap;
}

#user-input {
  flex: 1;
  background: #0f172a;
  border: 2px solid var(--border);
  border-radius: 14px;
  padding: 0.9rem 1.2rem;
  font-size: 1.3rem;
  color: var(--text);
  font-family: 'Courier New', monospace;
  outline: none;
  transition: border-color 0.2s;
  min-width: 200px;
}

#user-input:focus {
  border-color: var(--primary);
}
#user-input:disabled {
  opacity: 0.6;
}

.btn {
  padding: 0.8rem 1.8rem;
  border: none;
  border-radius: 14px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.15s;
  background: var(--border);
  color: var(--text);
  white-space: nowrap;
}

.btn-primary {
  background: var(--primary);
  color: #0f172a;
}
.btn-primary:hover:not(:disabled) {
  filter: brightness(1.15);
  transform: scale(1.02);
}
.btn-success {
  background: var(--success);
  color: #0f172a;
}
.btn-success:hover:not(:disabled) {
  filter: brightness(1.15);
  transform: scale(1.02);
}
.btn-danger {
  background: var(--danger);
  color: #0f172a;
}
.btn-danger:hover:not(:disabled) {
  filter: brightness(1.15);
  transform: scale(1.02);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.preview-box {
  background: #0f172a;
  border-radius: 14px;
  padding: 0.7rem 1.2rem;
  font-size: 1.2rem;
  border: 1px solid var(--border);
  min-height: 48px;
  margin-top: 0.3rem;
  font-family: 'Courier New', monospace;
  word-break: break-all;
}

.preview-box .preview-label {
  color: #94a3b8;
  font-size: 0.85rem;
  margin-right: 0.5rem;
  font-family: 'Segoe UI', sans-serif;
}

.kbd-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0.8rem 0 0.4rem;
  justify-content: center;
}

.kbd-btn {
  background: var(--kbd-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.4rem 0.9rem;
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--text);
  cursor: pointer;
  transition: all 0.1s;
  font-family: 'Courier New', monospace;
  min-width: 40px;
  text-align: center;
}

.kbd-btn:hover:not(:disabled) {
  background: #3b4d66;
  transform: translateY(-2px);
}
.kbd-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.stats {
  margin-top: 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.stats-text {
  font-size: 1rem;
  color: #cbd5e1;
}

.stats-text span {
  font-weight: 600;
  color: var(--primary);
}

.action-btns {
  display: flex;
  gap: 0.6rem;
}

@media (max-width: 600px) {
  .container {
    padding: 1.2rem;
  }
  .question-box {
    font-size: 1.2rem;
    padding: 1.2rem;
  }
  #user-input {
    font-size: 1rem;
    padding: 0.7rem 1rem;
  }
  .kbd-btn {
    padding: 0.3rem 0.6rem;
    font-size: 1rem;
    min-width: 32px;
  }
  .btn {
    padding: 0.6rem 1.2rem;
    font-size: 0.9rem;
  }
}