:root {
  --primary-bg: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --secondary-bg: rgba(255, 255, 255, 0.1);
  --text-color: #ffffff;
  --text-bg: #ffffff;
  --text-input-color: #333333;
  --border-color: rgba(255, 255, 255, 0.2);
  --shadow: 0 8px 32px rgba(31, 38, 135, 0.37);
  --accent-color: #667eea;
  --success-color: #4ade80;
  --warning-color: #fbbf24;
  --error-color: #f87171;
}

[data-theme="light"] {
  --primary-bg: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  --secondary-bg: rgba(255, 255, 255, 0.8);
  --text-color: #333333;
  --text-bg: #ffffff;
  --text-input-color: #333333;
  --border-color: rgba(0, 0, 0, 0.1);
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
  --accent-color: #6366f1;
}

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

body {
  font-family: 'Roboto', sans-serif;
  background: var(--primary-bg);
  color: var(--text-color);
  margin: 0;
  padding: 20px;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: all 0.3s ease;
}

.container {
  text-align: center;
  max-width: 900px;
  width: 100%;
  background: var(--secondary-bg);
  padding: 40px;
  border-radius: 20px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
}

.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
  flex-wrap: wrap;
  gap: 15px;
}

.app-header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  background: linear-gradient(45deg, var(--accent-color), var(--success-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin: 0;
}

.theme-toggle {
  background: var(--secondary-bg);
  border: 2px solid var(--border-color);
  border-radius: 50%;
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 1.5rem;
}

.theme-toggle:hover {
  transform: scale(1.1);
  background: var(--accent-color);
}

.progress-container {
  width: 100%;
  height: 8px;
  background: var(--border-color);
  border-radius: 4px;
  margin-bottom: 25px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-color), var(--success-color));
  width: 100%;
  border-radius: 4px;
  transition: width 1s linear;
  animation: shimmer 2s infinite;
}

@keyframes shimmer {
  0% { opacity: 0.8; }
  50% { opacity: 1; }
  100% { opacity: 0.8; }
}

.test-box {
  margin-top: 20px;
}

#text-display {
  background: var(--text-bg);
  color: var(--text-input-color);
  padding: 25px;
  border-radius: 15px;
  font-size: 1.3rem;
  min-height: 140px;
  margin-bottom: 20px;
  line-height: 1.6;
  border: 2px solid var(--border-color);
  word-wrap: break-word;
  letter-spacing: 0.5px;
}

#text-input {
  width: 100%;
  height: 120px;
  font-size: 1.2rem;
  padding: 20px;
  border-radius: 15px;
  border: 2px solid var(--border-color);
  outline: none;
  background: var(--text-bg);
  color: var(--text-input-color);
  resize: none;
  font-family: 'Roboto', sans-serif;
  transition: all 0.3s ease;
}

#text-input:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

#text-input:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.stats {
  margin: 25px 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 20px;
}

.stat-item {
  background: var(--secondary-bg);
  padding: 20px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  transition: transform 0.3s ease;
}

.stat-item:hover {
  transform: translateY(-2px);
}

.stat-label {
  display: block;
  font-size: 0.9rem;
  opacity: 0.8;
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.stat-value {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-color);
}

.controls {
  display: flex;
  gap: 20px;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 30px;
}

.time-selector {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.time-selector label {
  font-size: 0.9rem;
  opacity: 0.9;
}

#time-select {
  background: var(--text-bg);
  color: var(--text-input-color);
  border: 2px solid var(--border-color);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 1rem;
  cursor: pointer;
  outline: none;
}

#time-select:focus {
  border-color: var(--accent-color);
}

.primary-btn, .secondary-btn {
  padding: 12px 24px;
  font-size: 1rem;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.3s ease;
  min-width: 120px;
}

.primary-btn {
  background: var(--accent-color);
  color: white;
}

.primary-btn:hover:not(:disabled) {
  background: var(--success-color);
  transform: translateY(-2px);
}

.secondary-btn {
  background: transparent;
  color: var(--text-color);
  border: 2px solid var(--border-color);
}

.secondary-btn:hover:not(:disabled) {
  background: var(--border-color);
}

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

/* Mobile Responsive Design */
@media (max-width: 768px) {
  body {
    padding: 10px;
  }
  
  .container {
    padding: 25px;
    border-radius: 15px;
  }
  
  .app-header h1 {
    font-size: 2rem;
  }
  
  .app-header {
    justify-content: center;
    text-align: center;
  }
  
  .theme-toggle {
    width: 45px;
    height: 45px;
    font-size: 1.3rem;
  }
  
  #text-display {
    font-size: 1.1rem;
    padding: 20px;
    min-height: 120px;
  }
  
  #text-input {
    height: 100px;
    font-size: 1.1rem;
    padding: 15px;
  }
  
  .stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
  }
  
  .stat-item {
    padding: 15px;
  }
  
  .stat-value {
    font-size: 1.5rem;
  }
  
  .controls {
    flex-direction: column;
    gap: 15px;
  }
  
  .primary-btn, .secondary-btn {
    width: 100%;
    max-width: 200px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 20px;
  }
  
  .app-header h1 {
    font-size: 1.8rem;
  }
  
  .stats {
    grid-template-columns: 1fr;
  }
  
  #text-display {
    font-size: 1rem;
    padding: 15px;
  }
  
  #text-input {
    font-size: 1rem;
  }
}