:root {
  --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --primary-color: #764ba2;
  --secondary-color: #667eea;
  --bg-color: #f0f2f5;
  --card-bg: rgba(255, 255, 255, 0.95);
  --text-main: #2d3748;
  --text-sub: #718096;
  --border-color: #e2e8f0;
  --input-bg: #f7fafc;
  --radius: 24px;
  --shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.1);
}

/* 暗黑模式适配 */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-color: #1a202c;
    --card-bg: rgba(30, 41, 59, 0.95);
    --text-main: #f7fafc;
    --text-sub: #a0aec0;
    --border-color: #4a5568;
    --input-bg: #2d3748;
    --shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.3);
  }
  .shape {
    opacity: 0.3;
  }
  .upload-area {
    background: rgba(255, 255, 255, 0.05);
    border-color: #4a5568;
  }
  .upload-area:hover {
    background: rgba(255, 255, 255, 0.1);
  }
  .tab-btn.active {
    background: #4a5568;
    color: #fff;
  }
  .result-area {
    background: rgba(255, 255, 255, 0.05);
  }
  textarea:focus,
  input[type="text"]:focus {
    background: #2d3748;
  }
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  -webkit-tap-highlight-color: transparent;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 20px;
  overflow-x: hidden;
  position: relative;
  transition: background-color 0.3s;
}

.background-shapes {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}

.shape {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.6;
}
.shape-1 {
  top: -100px;
  left: -100px;
  width: 500px;
  height: 500px;
  background: linear-gradient(120deg, #a18cd1 0%, #fbc2eb 100%);
}
.shape-2 {
  bottom: -150px;
  right: -150px;
  width: 600px;
  height: 600px;
  background: linear-gradient(120deg, #8fd3f4 0%, #84fab0 100%);
}

.container {
  background: var(--card-bg);
  width: 100%;
  max-width: 440px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  position: relative;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  transition: background 0.3s;
}

.header {
  padding: 25px 25px 10px;
  text-align: center;
}
.header h2 {
  font-size: 1.5rem;
  font-weight: 800;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.5px;
}

.tabs {
  display: flex;
  background: var(--input-bg);
  margin: 15px 25px;
  padding: 5px;
  border-radius: 16px;
  position: relative;
  z-index: 5;
}
.tab-btn {
  flex: 1;
  padding: 10px;
  border: none;
  background: transparent;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-sub);
  transition: all 0.3s ease;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}
.tab-btn.active {
  background: #fff;
  color: var(--primary-color);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.tab-content {
  display: none;
  padding: 10px 25px 30px;
}
.tab-content.active {
  display: block;
  animation: fadeIn 0.4s ease-out;
}

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

.form-group {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-bottom: 8px;
  font-size: 13px;
  font-weight: 700;
  color: var(--text-sub);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

textarea,
input[type="text"] {
  width: 100%;
  padding: 16px;
  border: 2px solid transparent;
  border-radius: 16px;
  font-size: 15px;
  transition: all 0.3s;
  outline: none;
  background: var(--input-bg);
  color: var(--text-main);
}
textarea:focus,
input[type="text"]:focus {
  background: #fff;
  border-color: #a18cd1;
  box-shadow: 0 0 0 4px rgba(161, 140, 209, 0.15);
}
textarea {
  resize: none;
  min-height: 100px;
}

/* 清除按钮 */
.clear-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  background: transparent;
  border: none;
  color: var(--text-sub);
  cursor: pointer;
  padding: 5px;
  opacity: 0.6;
  transition: 0.2s;
  z-index: 5;
}
.clear-btn:hover {
  opacity: 1;
  color: var(--primary-color);
}

.btn {
  width: 100%;
  padding: 16px;
  background: var(--primary-gradient);
  color: white;
  border: none;
  border-radius: 16px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  box-shadow: 0 10px 20px -5px rgba(118, 75, 162, 0.4);
  position: relative;
  z-index: 10;
}
.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 15px 30px -5px rgba(118, 75, 162, 0.5);
}
.btn:active {
  transform: translateY(0);
}
.btn-danger {
  background: #ff6b6b;
  box-shadow: 0 10px 20px -5px rgba(255, 107, 107, 0.4);
}
.btn-outline {
  background: transparent;
  border: 2px solid var(--border-color);
  color: var(--text-main);
  box-shadow: none;
}
.btn-outline:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
  background: var(--card-bg);
  transform: translateY(-2px);
}

.divider {
  display: flex;
  align-items: center;
  text-align: center;
  margin: 20px 0;
  color: var(--text-sub);
  font-size: 12px;
  font-weight: 700;
}
.divider::before,
.divider::after {
  content: "";
  flex: 1;
  border-bottom: 2px dashed var(--border-color);
}
.divider span {
  padding: 0 10px;
}

.upload-area {
  border: 2px dashed var(--text-sub);
  border-radius: 20px;
  padding: 30px 20px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  background: var(--card-bg);
  opacity: 0.8;
  position: relative;
  overflow: hidden;
  z-index: 1;
}
.upload-area:hover {
  border-color: var(--secondary-color);
  opacity: 1;
  transform: scale(1.02);
}
.upload-icon {
  font-size: 32px;
  color: var(--secondary-color);
  margin-bottom: 10px;
}
.upload-area input {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

.result-area {
  margin-top: 25px;
  text-align: center;
  padding: 24px;
  background: var(--card-bg);
  border-radius: 20px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
  display: none;
  animation: popIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
@keyframes popIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}
.result-area.show {
  display: block;
}
.result-header {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-sub);
  text-transform: uppercase;
  margin-bottom: 10px;
}
.decode-result {
  font-size: 16px;
  color: var(--text-main);
  word-break: break-all;
  margin-bottom: 20px;
  line-height: 1.5;
  font-weight: 500;
}

#canvas-container canvas {
  max-width: 100%;
  border-radius: 12px;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.scan-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: 16px;
  pointer-events: none;
  box-shadow: inset 0 0 0 2px rgba(255, 255, 255, 0.2);
}
.scan-overlay::after {
  content: "";
  position: absolute;
  top: 20%;
  left: 15%;
  width: 70%;
  height: 2px;
  background: #00f2fe;
  box-shadow: 0 0 10px #00f2fe;
  animation: scanMove 2s infinite linear;
  opacity: 0.8;
}
@keyframes scanMove {
  0% {
    top: 15%;
    opacity: 0;
  }
  50% {
    opacity: 1;
  }
  100% {
    top: 85%;
    opacity: 0;
  }
}