:root {
  --color-bg: #ffffff;
  --color-text: #1f2937;
  --color-button-idle: #3b82f6;
  --color-button-hover: #2563eb;
  --color-button-recording: #ef4444;
  --color-button-recording-hover: #dc2626;
  --color-error: #dc2626;
  --color-loading: #6b7280;

  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  --border-radius: 1rem;
  --letter-size: 4rem;
  --record-button-size: 6rem;

  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--spacing-lg);
}

#app {
  width: 100%;
  max-width: 1200px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xl);
}

/* Record Button */
#record-button {
  width: var(--record-button-size);
  height: var(--record-button-size);
  border-radius: 50%;
  border: none;
  background-color: var(--color-button-idle);
  color: white;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  transition: all 0.2s ease;
  position: relative;
  overflow: hidden;
}

#record-button:hover:not(:disabled) {
  background-color: var(--color-button-hover);
  transform: scale(1.05);
}

#record-button:active:not(:disabled) {
  transform: scale(0.95);
}

#record-button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

#record-button.recording {
  background-color: var(--color-button-recording);
  animation: pulse 1.5s ease-in-out infinite;
}

#record-button.recording:hover:not(:disabled) {
  background-color: var(--color-button-recording-hover);
}

@keyframes pulse {
  0%, 100% {
    box-shadow: var(--shadow-lg);
  }
  50% {
    box-shadow: 0 0 0 8px rgba(239, 68, 68, 0.3);
  }
}

/* Button Icons */
#record-button::before {
  content: '';
  position: absolute;
  width: 40%;
  height: 40%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: white;
  border-radius: 50%;
  transition: all 0.2s ease;
}

#record-button.recording::before {
  border-radius: 15%;
  width: 35%;
  height: 35%;
}

/* Text Container */
#text-container {
  width: 100%;
  min-height: 200px;
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  justify-content: center;
  align-items: flex-start;
  padding: var(--spacing-md);
}

/* Letter Boxes */
.letter-box {
  width: var(--letter-size);
  height: var(--letter-size);
  border: none;
  border-radius: var(--border-radius);
  font-size: 2rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: all 0.15s ease;
}

.letter-box:hover {
  transform: scale(1.1) rotate(-2deg);
  box-shadow: var(--shadow-lg);
}

.letter-box:active {
  transform: scale(0.95);
}

/* Letter Space (for word separators) */
.letter-space {
  width: var(--spacing-md);
  height: var(--letter-size);
}

/* Loading State */
.loading {
  font-size: 1.5rem;
  color: var(--color-loading);
  text-align: center;
  animation: fadeIn 0.3s ease;
}

/* Error Messages */
.error {
  color: var(--color-error);
  text-align: center;
  font-size: 1.25rem;
  padding: var(--spacing-lg);
  animation: fadeIn 0.3s ease;
}

.browser-error {
  max-width: 600px;
}

.browser-error h2 {
  margin-bottom: var(--spacing-md);
  font-size: 2rem;
}

.browser-error p {
  margin-bottom: var(--spacing-sm);
  line-height: 1.6;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --letter-size: 3rem;
    --record-button-size: 5rem;
    --spacing-lg: 1.5rem;
  }

  body {
    padding: var(--spacing-md);
  }

  .letter-box {
    font-size: 1.5rem;
  }

  .error {
    font-size: 1rem;
  }

  .browser-error h2 {
    font-size: 1.5rem;
  }
}

@media (max-width: 480px) {
  :root {
    --letter-size: 2.5rem;
    --record-button-size: 4.5rem;
    --spacing-sm: 0.75rem;
  }

  .letter-box {
    font-size: 1.25rem;
  }
}