diff --git a/assets/css/style.css b/assets/css/style.css
index 0c0e421..c9692af 100644
--- a/assets/css/style.css
+++ b/assets/css/style.css
@@ -205,13 +205,14 @@ nav a {
     color: #3a300a;
 }
 
-/* 淪陷瞬間 · 全員發瘋：僅第一層選單向下；第二層起向右飛出（≥1025px），小螢幕改直向堆疊 */
+/* 淪陷瞬間 · 全員發瘋：第一層向下；第二／三層向右飛出（≤1024px 改直向堆疊） */
 .portal-nav .portal-submenu .portal-nav__subgroup {
     position: relative;
     z-index: 0;
     margin-top: 4px;
     padding-top: 6px;
     border-top: 1px solid rgba(0, 0, 0, 0.07);
+    list-style: none;
 }
 
 .portal-nav .portal-submenu .portal-nav__subgroup:hover {
@@ -227,6 +228,7 @@ nav a {
     font-size: 0.84rem;
     font-weight: 700;
     letter-spacing: 0;
+    white-space: nowrap;
 }
 
 .portal-nav .portal-submenu .portal-nav__subgroup-head::after {
@@ -249,14 +251,18 @@ nav a {
     flex-direction: column;
     gap: 4px;
     position: absolute;
-    left: calc(100% + 3px);
+    left: calc(100% + 6px);
     top: 0;
     min-width: 216px;
+    width: max-content;
+    max-width: min(280px, 92vw);
     background: #fff;
     border-radius: 12px;
     box-shadow: 0 12px 32px rgba(0, 0, 0, 0.14);
     border: 1px solid rgba(0, 0, 0, 0.06);
     z-index: 96;
+    overflow: visible;
+    box-sizing: border-box;
 }
 
 .portal-nav .portal-nav__subgroup:hover>.portal-submenu-nested,
@@ -266,6 +272,14 @@ nav a {
 
 .portal-nav .portal-submenu-nested li {
     padding-bottom: 0;
+    list-style: none;
+}
+
+.portal-nav .portal-submenu-nested a {
+    display: block;
+    width: 100%;
+    white-space: nowrap;
+    box-sizing: border-box;
 }
 
 .portal-nav .portal-submenu .portal-nav__subgroup--nested {
@@ -274,6 +288,7 @@ nav a {
     margin: 0;
     padding: 0;
     border: 0;
+    list-style: none;
 }
 
 .portal-nav .portal-submenu .portal-nav__subgroup--nested:hover {
@@ -288,6 +303,7 @@ nav a {
     font-size: 0.82rem;
     color: #4a4a4a;
     font-weight: 700;
+    white-space: nowrap;
 }
 
 .portal-nav .portal-nav__subgroup-head--nested::after {
@@ -310,14 +326,17 @@ nav a {
     flex-direction: column;
     gap: 2px;
     position: absolute;
-    left: calc(100% + 3px);
+    left: calc(100% + 6px);
     top: 0;
     min-width: 200px;
+    width: max-content;
+    max-width: min(260px, 92vw);
     background: #fff;
     border-radius: 12px;
     box-shadow: 0 14px 36px rgba(0, 0, 0, 0.16);
     border: 1px solid rgba(0, 0, 0, 0.07);
     z-index: 102;
+    box-sizing: border-box;
 }
 
 .portal-nav .portal-nav__subgroup--nested:hover>.portal-submenu-nested--tier3,
@@ -336,9 +355,10 @@ nav a {
     .portal-nav .portal-nav__subgroup:hover>.portal-submenu-nested,
     .portal-nav .portal-nav__subgroup:focus-within>.portal-submenu-nested {
         position: static;
-        display: flex !important;
+        display: none;
         width: 100%;
         min-width: 0;
+        max-width: none;
         margin: 8px 0 0;
         padding: 8px 0 8px 12px;
         border: 0;
@@ -347,18 +367,30 @@ nav a {
         box-shadow: none;
     }
 
+    .portal-nav .portal-nav__subgroup:hover>.portal-submenu-nested,
+    .portal-nav .portal-nav__subgroup:focus-within>.portal-submenu-nested {
+        display: flex;
+    }
+
     .portal-nav .portal-submenu-nested--tier3,
     .portal-nav .portal-nav__subgroup--nested:hover>.portal-submenu-nested--tier3,
     .portal-nav .portal-nav__subgroup--nested:focus-within>.portal-submenu-nested--tier3 {
         position: static;
-        display: flex !important;
+        display: none;
+        width: 100%;
+        min-width: 0;
+        max-width: none;
         margin: 8px 0 0 10px;
         padding: 6px 0 6px 12px;
         border: 0;
         border-left: 2px solid rgba(255, 180, 0, 0.38);
         border-radius: 0;
         box-shadow: none;
-        min-width: 0;
+    }
+
+    .portal-nav .portal-nav__subgroup--nested:hover>.portal-submenu-nested--tier3,
+    .portal-nav .portal-nav__subgroup--nested:focus-within>.portal-submenu-nested--tier3 {
+        display: flex;
     }
 }
 
@@ -471,9 +503,9 @@ a.btn[data-coming-soon="true"],
     display: none !important;
 }
 
-.portal-nav li:hover>.portal-submenu,
-.portal-nav li:focus-within>.portal-submenu,
-.portal-nav li.open>.portal-submenu {
+.portal-nav>ul>li:hover>.portal-submenu,
+.portal-nav>ul>li:focus-within>.portal-submenu,
+.portal-nav>ul>li.open>.portal-submenu {
     display: grid;
     gap: 6px;
 }
@@ -513,7 +545,7 @@ footer {
     padding: 0.5rem;
 }
 
-/* 頂欄主標／副標字級與色見 .site-header-inner（對齊 extra/totoga2-copy-ebook.html） */
+/* 頂欄主標／副標見 .site-header-inner；首頁 #origin .hero 內已套相同 class */
 
 .hero p {
     font-size: 1.2rem;
@@ -1467,19 +1499,10 @@ footer a .mark_b {
     padding-right: 10px;
 }
 
-.map-page .portal-nav .portal-submenu .portal-nav__subgroup-head::after {
-    right: auto;
-    left: 10px;
-}
-
-.map-page .portal-nav .portal-nav__subgroup>.portal-submenu-nested {
-    left: auto;
-    right: calc(100% + 3px);
-}
-
 .map-page .portal-nav .portal-submenu-nested a {
-    align-items: flex-end;
+    display: block;
     text-align: right;
+    white-space: nowrap;
 }
 
 .map-page .portal-nav .portal-nav__subgroup-head--nested {
@@ -1489,14 +1512,27 @@ footer a .mark_b {
     padding-right: 10px;
 }
 
-.map-page .portal-nav .portal-nav__subgroup-head--nested::after {
-    right: auto;
-    left: 8px;
-}
+@media (min-width: 1025px) {
 
-.map-page .portal-nav .portal-submenu-nested--tier3 {
-    left: auto;
-    right: calc(100% + 3px);
+    .map-page .portal-nav .portal-submenu .portal-nav__subgroup-head::after {
+        right: auto;
+        left: 10px;
+    }
+
+    .map-page .portal-nav .portal-nav__subgroup>.portal-submenu-nested {
+        left: auto;
+        right: calc(100% + 6px);
+    }
+
+    .map-page .portal-nav .portal-nav__subgroup-head--nested::after {
+        right: auto;
+        left: 8px;
+    }
+
+    .map-page .portal-nav li.portal-nav__subgroup--nested>.portal-submenu-nested--tier3 {
+        left: auto;
+        right: calc(100% + 6px);
+    }
 }
 
 @media (max-width: 1024px) {
@@ -1558,7 +1594,15 @@ header.map-archive-header {
     box-sizing: border-box;
 }
 
-/* 全站頂欄標題語彙：黃色氣球底圖上用深灰字（易讀）；套在 .header-inner.site-header-inner，首頁 #origin 內亦然 */
+/* 全站頂欄標題語彙：黃色氣球底圖上用深灰字；.header-inner.site-header-inner（首頁 #origin .hero 內同 class） */
+.site-header-inner {
+    width: 100%;
+    max-width: min(40rem, 94vw);
+    margin-inline: auto;
+    text-align: center;
+    box-sizing: border-box;
+}
+
 .site-header-inner .main-title {
     font-size: clamp(2rem, 4.5vw, 3.2rem);
     font-weight: 900;
@@ -1569,26 +1613,33 @@ header.map-archive-header {
 }
 
 .site-header-inner .subtitle-wrap {
-    margin-top: 20px;
+    width: 100%;
+    margin: 20px auto 0;
+    padding: 0 0.75rem;
     display: flex;
     align-items: center;
     justify-content: center;
+    box-sizing: border-box;
 }
 
 .site-header-inner .subtitle-wrap::before,
 .site-header-inner .subtitle-wrap::after {
     content: "";
-    flex: 1;
+    display: block;
+    flex: 1 1 56px;
+    min-width: 28px;
     height: 3px;
     background-color: #5c5c5c;
     max-width: 56px;
+    opacity: 1;
 }
 
 .site-header-inner .sub-title {
+    flex: 0 0 auto;
     font-size: 0.92rem;
     letter-spacing: 4px;
     color: var(--text-muted, #888);
-    margin: 0;
+    margin: 0 18px;
     text-transform: uppercase;
 }