/* CSS Variables */
:root {
  --primary: #667eea;
  --secondary: #764ba2;
  --success: #4caf50;
  --warning: #ff9800;
  --danger: #f44336;
  --bg: #f5f7fa;
  --card-bg: #ffffff;
  --text: #333333;
  --border: #e0e0e0;
  --shadow: rgba(0, 0, 0, 0.1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, sans-serif;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text);
  padding: 20px;
}

/* Container and Card */
.container {
  width: 100%;
  max-width: 480px;
}

.card {
  background: var(--card-bg);
  border-radius: 20px;
  padding: 40px 30px;
  box-shadow: 0 20px 60px var(--shadow);
  animation: slideIn 0.5s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Header */
header {
  text-align: center;
  margin-bottom: 30px;
}

header h1 {
  font-size: 28px;
  margin-bottom: 8px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

header p {
  color: #666;
  font-size: 16px;
}

/* Password Display */
.password-display {
  position: relative;
  margin-bottom: 20px;
}

#passwordOutput {
  width: 100%;
  padding: 16px 50px 16px 16px;
  font-size: 18px;
  font-family: "Courier New", monospace;
  border: 2px solid var(--border);
  border-radius: 12px;
  background: #f8f9fa;
  color: var(--text);
  transition: all 0.3s ease;
}

#passwordOutput:focus {
  outline: none;
  border-color: var(--primary);
  background: white;
}

.copy-btn {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--primary);
  border: none;
  padding: 10px;
  border-radius: 8px;
  cursor: pointer;
  color: white;
  transition: all 0.3s ease;
}

.copy-btn:hover {
  background: var(--secondary);
  transform: translateY(-50%) scale(1.1);
}

.copy-btn:active {
  transform: translateY(-50%) scale(0.95);
}

/* Strength Indicator */
.strength-indicator {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 25px;
  padding: 15px;
  background: #f8f9fa;
  border-radius: 10px;
}

.strength-text {
  font-size: 14px;
  color: #666;
}

.strength-bars {
  display: flex;
  gap: 4px;
  flex: 1;
}

.strength-bar {
  height: 6px;
  width: 100%;
  background: var(--border);
  border-radius: 3px;
  transition: all 0.3s ease;
}

.strength-label {
  font-size: 14px;
  font-weight: 600;
  min-width: 60px;
  text-align: right;
}

/* Strength States */
.strength-weak .strength-bar:nth-child(1) {
  background: var(--danger);
}

.strength-weak .strength-label {
  color: var(--danger);
}

.strength-medium .strength-bar:nth-child(1),
.strength-medium .strength-bar:nth-child(2) {
  background: var(--warning);
}

.strength-medium .strength-label {
  color: var(--warning);
}

.strength-strong .strength-bar {
  background: var(--success);
}

.strength-strong .strength-label {
  color: var(--success);
}

/* Form Group */
.form-group {
  margin-bottom: 25px;
}

.form-group label {
  display: block;
  margin-bottom: 10px;
  font-weight: 500;
  color: var(--text);
}

#lengthValue {
  color: var(--primary);
  font-weight: 700;
}

/* Slider */
.slider {
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background: var(--border);
  outline: none;
  -webkit-appearance: none;
  cursor: pointer;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  transition: all 0.3s ease;
}

.slider::-webkit-slider-thumb:hover {
  background: var(--secondary);
  transform: scale(1.2);
}

.slider::-moz-range-thumb {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  border: none;
  transition: all 0.3s ease;
}

.slider::-moz-range-thumb:hover {
  background: var(--secondary);
  transform: scale(1.2);
}

/* Checkboxes */
.options {
  display: grid;
  grid-template-columns: 1fr;
  gap: 15px;
  margin-bottom: 30px;
}

.checkbox-container {
  display: flex;
  align-items: center;
  cursor: pointer;
  padding: 12px;
  border-radius: 10px;
  transition: background 0.3s ease;
}

.checkbox-container:hover {
  background: #f8f9fa;
}

.checkbox-container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
}

.checkmark {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border);
  border-radius: 6px;
  margin-right: 12px;
  position: relative;
  transition: all 0.3s ease;
}

.checkbox-container input:checked ~ .checkmark {
  background: var(--primary);
  border-color: var(--primary);
}

.checkmark:after {
  content: "";
  position: absolute;
  display: none;
  left: 6px;
  top: 2px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.checkbox-container input:checked ~ .checkmark:after {
  display: block;
}

.label-text {
  font-size: 14px;
  color: var(--text);
}

/* Generate Button */
.generate-btn {
  width: 100%;
  padding: 16px;
  font-size: 16px;
  font-weight: 600;
  color: white;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.generate-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

.generate-btn:active {
  transform: translateY(0);
}

/* Copy Feedback */
.copy-feedback {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--success);
  color: white;
  padding: 12px 24px;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-20px);
  transition: all 0.3s ease;
}

.copy-feedback.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 768px) {
  .card {
    padding: 30px 20px;
  }

  header h1 {
    font-size: 24px;
  }

  #passwordOutput {
    font-size: 16px;
  }

  .generate-btn {
    font-size: 14px;
    padding: 14px;
  }
}

@media (max-width: 480px) {
  body {
    padding: 10px;
  }

  .card {
    padding: 25px 15px;
  }

  header h1 {
    font-size: 22px;
  }

  header p {
    font-size: 14px;
  }

  .strength-indicator {
    flex-wrap: wrap;
    gap: 8px;
  }

  .strength-text {
    width: 100%;
  }

  .copy-feedback {
    top: 10px;
    right: 10px;
    left: 10px;
    text-align: center;
  }
}