:root {
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --success-color: #10b981;
  --success-hover: #059669;
  --bg-color: #f3f4f6;
  --card-bg: rgba(255, 255, 255, 0.85);
  --text-main: #1f2937;
  --text-muted: #6b7280;
  --border-color: #e5e7eb;
  --radius: 12px;
  --font-family: 'Inter', 'Noto Sans SC', sans-serif;
}

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

body {
  font-family: var(--font-family);
  background: linear-gradient(135deg, #e0eafc 0%, #cfdef3 100%);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}

.app-container {
  display: flex;
  width: 100%;
  max-width: 1400px;
  height: 90vh;
  gap: 24px;
}

.sidebar {
  width: 400px;
  flex-shrink: 0;
  overflow-y: auto;
  padding: 30px;
  border-radius: var(--radius);
  background: var(--card-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
  display: flex;
  flex-direction: column;
}

/* 隐藏侧边栏滚动条 */
.sidebar::-webkit-scrollbar {
  width: 6px;
}
.sidebar::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 4px;
}

.header {
  margin-bottom: 24px;
  text-align: center;
}

.header h1 {
  font-size: 24px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 8px;
}

.header p {
  font-size: 14px;
  color: var(--text-muted);
}

.form-container {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-row {
  display: flex;
  gap: 12px;
}

.form-group {
  display: flex;
  flex-direction: column;
  flex: 1;
}

.form-group label {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 6px;
  color: #475569;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  background-color: #fff;
  font-family: var(--font-family);
  font-size: 14px;
  color: var(--text-main);
  transition: all 0.2s ease;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.file-upload {
  margin-top: 8px;
}

.file-upload label {
  font-weight: 600;
}

.file-upload input[type="file"] {
  padding: 8px 0;
  border: none;
  font-size: 13px;
}

.actions {
  margin-top: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.btn {
  padding: 12px;
  border-radius: 8px;
  border: none;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  transition: transform 0.1s, box-shadow 0.2s, background-color 0.2s;
  text-align: center;
  font-family: var(--font-family);
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  box-shadow: 0 6px 16px rgba(59, 130, 246, 0.4);
}

.btn-success {
  background-color: var(--success-color);
  color: white;
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}

.btn-success:hover {
  background-color: var(--success-hover);
  box-shadow: 0 6px 16px rgba(16, 185, 129, 0.4);
}

.preview-area {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
  background: var(--card-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: var(--radius);
  border: 1px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
  padding: 20px;
  overflow: hidden;
}

.canvas-wrapper {
  max-width: 100%;
  max-height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

/* 画布添加投影以更加拟真 */
#certCanvas {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  box-shadow: 0 20px 40px rgba(0,0,0,0.15);
  border-radius: 4px;
  background: white; /* fallback bg */
}

/* 响应式调整 */
@media (max-width: 1024px) {
  .app-container {
    flex-direction: column;
    height: auto;
  }
  .sidebar {
    width: 100%;
  }
  .preview-area {
    min-height: 50vh;
  }
}