feat: phase2 immersive journey (semantic scene transitions + camera feel)

themes/dreamscape/assets/js/dreamscape.js

@@ -134,15 +134,42 @@
         });
     }
 
-    // ═══ 场景滚动进度 + 旅程节点高亮 ═══
+    // ═══ 场景滚动进度 + 旅程节点高亮 + 语义场景切换 ═══
     function setupStoryJourney() {
         const body = document.getElementById('storyBody');
         const progress = document.getElementById('storyProgress');
+        const article = document.querySelector('.story-journey');
         if (!body || !progress) return;
 
         const scenes = Array.from(body.querySelectorAll(':scope > p'));
         if (!scenes.length) return;
 
+        const sceneProfiles = [
+            { key: 'starsea', keywords: ['星海', '星辰', '光河', '漂浮', '夜晚'] },
+            { key: 'crystal', keywords: ['水晶', '冰晶', '棱镜', '森林'] },
+            { key: 'calling', keywords: ['使命', '记录', '召唤', '欢迎'] },
+            { key: 'void', keywords: ['深渊', '平静', '对话'] }
+        ];
+
+        const detectScene = (text) => {
+            let matched = 'void';
+            let best = 0;
+            for (const profile of sceneProfiles) {
+                let score = 0;
+                for (const kw of profile.keywords) {
+                    if (text.includes(kw)) score++;
+                }
+                if (score > best) {
+                    best = score;
+                    matched = profile.key;
+                }
+            }
+            return matched;
+        };
+
+        let currentScene = '';
+        let shiftTimer;
+
         const onScroll = () => {
             const rect = body.getBoundingClientRect();
             const total = Math.max(body.scrollHeight - window.innerHeight, 1);
@@ -161,6 +188,21 @@
                 }
             });
             scenes.forEach((p, idx) => p.classList.toggle('active-scene', idx === activeIndex));
+
+            const activeText = scenes[activeIndex]?.innerText || '';
+            const scene = detectScene(activeText);
+            if (scene !== currentScene) {
+                currentScene = scene;
+                document.body.dataset.scene = scene;
+                document.body.classList.add('scene-shift');
+                clearTimeout(shiftTimer);
+                shiftTimer = setTimeout(() => document.body.classList.remove('scene-shift'), 420);
+            }
+
+            if (article) {
+                const camY = scrolled * 0.018;
+                article.style.transform = `translate3d(0, ${camY}px, 0)`;
+            }
         };
 
         window.addEventListener('scroll', onScroll, { passive: true });