:root {
  --btn-bg: rgba(255,255,255,0.2);
  --btn-hover: rgba(255,255,255,0.3);
  --btn-active: rgba(255,255,255,0.4);
  --container-bg: rgba(255,255,255,0.15);
  --shadow: 0 8px 32px 0 rgba(31,38,135,0.37);
  --success-color: #4CAF50;
  --error-color: #f44336;
  --text-color: #333333;
  --border-color: rgba(255,255,255,0.3);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Poppins', sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  transition: background 0.8s ease;
}

.container {
  text-align: center;
  background: var(--container-bg);
  backdrop-filter: blur(15px);
  border-radius: 25px;
  padding: 40px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border-color);
  max-width: 500px;
  width: 100%;
}

h1 {
  font-size: 2.5rem;
  color: var(--text-color);
  margin-bottom: 30px;
  font-weight: 700;
}

h3 {
  color: var(--text-color);
  margin: 20px 0 15px 0;
  font-weight: 600;
}

.color-display {
  position: relative;
  margin-bottom: 30px;
}

#color-box {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  border: 4px solid rgba(255,255,255,0.5);
  margin: 0 auto 20px;
  box-shadow: 
    inset 0 0 20px rgba(0,0,0,0.2),
    0 10px 30px rgba(0,0,0,0.3);
  transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #667eea 100%);
  position: relative;
  overflow: hidden;
}

#color-box::before {
  content: '';
  position: absolute;
  top: 20%;
  left: 20%;
  width: 30%;
  height: 30%;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  filter: blur(10px);
}

#color-code {
  font-size: 1.5rem;
  color: var(--text-color);
  margin: 10px 0;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
}

.copy-btn {
  background: var(--btn-bg);
  border: none;
  padding: 8px 12px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 1.2rem;
  margin-left: 10px;
  transition: all 0.2s ease;
  backdrop-filter: blur(5px);
}

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

.controls {
  display: flex;
  flex-direction: column;
  gap: 15px;
  margin-bottom: 30px;
}

.primary-btn, .secondary-btn {
  padding: 15px 30px;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-color);
  border: none;
  border-radius: 30px;
  cursor: pointer;
  backdrop-filter: blur(5px);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.primary-btn {
  background: linear-gradient(45deg, var(--btn-bg), var(--btn-hover));
  font-size: 1.2rem;
  padding: 18px 35px;
}

.secondary-btn {
  background: var(--btn-bg);
  font-size: 1rem;
}

.primary-btn:hover, .secondary-btn:hover {
  background: var(--btn-hover);
  transform: translateY(-2px);
  box-shadow: 0 12px 40px rgba(31,38,135,0.5);
}

.primary-btn:active, .secondary-btn:active {
  transform: translateY(0);
  background: var(--btn-active);
}

.palette-container, .saved-container {
  margin-top: 30px;
  padding-top: 20px;
  border-top: 1px solid var(--border-color);
  flex-direction: column;
  align-items: center;
  display: grid;
}

.palette-grid, .saved-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(50px, 1fr));
  gap: 10px;
  margin-bottom: 20px;
  width: 100%;
  justify-items: center;
}

.palette-color, .saved-color {
  width: 50px;
  height: 50px;
  border-radius: 12px;
  border: 2px solid rgba(255,255,255,0.3);
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
}

.palette-color:hover, .saved-color:hover {
  transform: scale(1.1);
  box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

.hidden {
  display: none;
}

.clear-btn {
  background: var(--btn-bg);
  color: var(--text-color);
  border: none;
  padding: 10px 20px;
  border-radius: 20px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.2s ease;
  margin-top: 10px;
  display: none; /* 기본적으로 숨김 */
}

.clear-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(244, 67, 54, 0.4);
  background: linear-gradient(45deg, #d32f2f, #c62828);
}

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

.toast {
  position: fixed;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(0,0,0,0.8);
  color: white;
  padding: 12px 24px;
  border-radius: 25px;
  font-weight: 600;
  opacity: 0;
  transition: all 0.3s ease;
  z-index: 1000;
  backdrop-filter: blur(10px);
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(-10px);
}

.toast.success {
  background: linear-gradient(45deg, var(--success-color), #66bb6a);
}

.toast.error {
  background: linear-gradient(45deg, var(--error-color), #ef5350);
}

/* 애니메이션 */
@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

@keyframes colorChange {
  0% { filter: hue-rotate(0deg); }
  100% { filter: hue-rotate(360deg); }
}

.generating {
  animation: pulse 0.6s ease-in-out;
}

.color-changing {
  animation: colorChange 0.5s ease-in-out;
}

/* 반응형 디자인 */
@media (max-width: 480px) {
  .container {
    padding: 30px 20px;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  #color-box {
    width: 150px;
    height: 150px;
  }
  
  .controls {
    gap: 10px;
  }
  
  .primary-btn, .secondary-btn {
    padding: 12px 25px;
    font-size: 1rem;
  }
  
  .palette-grid, .saved-grid {
    grid-template-columns: repeat(auto-fit, minmax(40px, 1fr));
  }
  
  .palette-color, .saved-color {
    width: 40px;
    height: 40px;
  }
}