feat: dark mode

src/app/globals.css

@@ -27,6 +27,9 @@ body {
 
 body {
   color: rgb(var(--foreground-rgb));
+}
+
+html:not(.dark) body {
   background: linear-gradient(
     180deg,
     #e6f3fb 0%,
@@ -99,3 +102,47 @@ body {
 *::-webkit-scrollbar {
   display: none; /* Chrome, Safari, Opera */
 }
+
+/* View Transitions API 动画 */
+@keyframes slide-from-top {
+  from {
+    clip-path: polygon(0 0, 100% 0, 100% 0, 0 0);
+  }
+  to {
+    clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
+  }
+}
+
+@keyframes slide-from-bottom {
+  from {
+    clip-path: polygon(0 100%, 100% 100%, 100% 100%, 0 100%);
+  }
+  to {
+    clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
+  }
+}
+
+::view-transition-old(root),
+::view-transition-new(root) {
+  animation-duration: 0.8s;
+  animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
+  animation-fill-mode: both;
+}
+
+/*
+  切换时，旧的视图不应该有动画，它应该在下面，等待被新的视图覆盖。
+  这可以防止在动画完成前，页面底部提前变色。
+*/
+::view-transition-old(root) {
+  animation: none;
+}
+
+/* 从浅色到深色：新内容（深色）从顶部滑入 */
+html.dark::view-transition-new(root) {
+  animation-name: slide-from-top;
+}
+
+/* 从深色到浅色：新内容（浅色）从底部滑入 */
+html:not(.dark)::view-transition-new(root) {
+  animation-name: slide-from-bottom;
+}