Changed around line 1
+ :root {
+ --primary-color: #d32f2f;
+ --secondary-color: #ffcdd2;
+ --accent-color: #ffeb3b;
+ --font-family: 'Georgia', serif;
+ --transition-speed: 0.5s;
+ }
+
+ * {
+ margin: 0;
+ padding: 0;
+ box-sizing: border-box;
+ }
+
+ body {
+ min-height: 100vh;
+ display: flex;
+ flex-direction: column;
+ align-items: center;
+ justify-content: center;
+ background: linear-gradient(135deg, #1a237e, #311b92);
+ color: white;
+ font-family: var(--font-family);
+ padding: 1rem;
+ }
+
+ main {
+ perspective: 1000px;
+ }
+
+ .card {
+ width: 300px;
+ height: 400px;
+ position: relative;
+ transform-style: preserve-3d;
+ transition: transform var(--transition-speed);
+ cursor: pointer;
+ }
+
+ .card.flipped {
+ transform: rotateY(180deg);
+ }
+
+ .card-front, .card-back {
+ width: 100%;
+ height: 100%;
+ position: absolute;
+ backface-visibility: hidden;
+ display: flex;
+ flex-direction: column;
+ align-items: center;
+ justify-content: center;
+ padding: 2rem;
+ border-radius: 15px;
+ box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
+ background: var(--secondary-color);
+ color: var(--primary-color);
+ text-align: center;
+ }
+
+ .card-back {
+ background: var(--primary-color);
+ color: white;
+ transform: rotateY(180deg);
+ }
+
+ h1, h2 {
+ margin-bottom: 1rem;
+ font-size: 1.8rem;
+ }
+
+ p {
+ margin: 0.5rem 0;
+ }
+
+ .chinese {
+ font-size: 1.2rem;
+ margin-top: 1rem;
+ }
+
+ button.flip-btn {
+ margin-top: 1.5rem;
+ padding: 0.5rem 1rem;
+ border: none;
+ border-radius: 5px;
+ background: var(--accent-color);
+ color: var(--primary-color);
+ cursor: pointer;
+ transition: background 0.3s;
+ }
+
+ button.flip-btn:hover {
+ background: #ffc107;
+ }
+
+ footer {
+ margin-top: 2rem;
+ text-align: center;
+ color: var(--secondary-color);
+ }
+
+ @media (max-width: 480px) {
+ .card {
+ width: 250px;
+ height: 350px;
+ }
+
+ h1, h2 {
+ font-size: 1.5rem;
+ }
+ }