fix(storybook): make page inner width responsive

src/components/story-page.css

@@ -1,8 +1,7 @@
 /* Storybook presentation only. Common page frame for representative Stories; all selectors stay inside .sb-page.
-   Inner (max 1280, gutter 16–40) and title (kicker 12 / title 28·36·700 / description, underlined) reuse Foundation / Color.
+   Inner (fluid, 60px each side; vertical gutter 16–40) and title (kicker 12 / title 28·36·700 / description, underlined) reuse Foundation / Color.
    Section reuses the Center Graphic / 교량 split: heading + description, a divider, then the specimen. */
 .sb-page {
-  --sb-page-max-width: 1280px;
   --sb-page-gutter: clamp(16px, 3vw, 40px);
   box-sizing: border-box;
   width: 100%;
@@ -13,17 +12,11 @@
 }
 .sb-page > .sb-page-inner {
   box-sizing: border-box;
-  /* Keep the established content width: the 1280px envelope includes both gutters. */
+  /* 2026-11-05 (user request): no max width; the Inner follows the page width and keeps 60px on each side. */
-  width: calc(min(100%, var(--sb-page-max-width)) - 2 * var(--sb-page-gutter));
+  width: calc(100% - 120px);
   min-width: 0;
   margin-inline: auto;
 }
-/* Wide screens (2026-10-22, user request): 80% of the viewport — 1536px at 1920px, 2048px at 2560px, 3072px at
-   3840px — growing with the screen (vw, so a scrollbar does not shrink it); never wider than the page minus the
-   gutters, so no horizontal scroll. Below 1920px the rule above applies. */
-@media (min-width: 1920px) {
-  .sb-page > .sb-page-inner { width: min(80vw, calc(100% - 2 * var(--sb-page-gutter))); }
-}
 
 .sb-page .sb-page-header {
   padding-bottom: 24px;