core2026/docs/frontend-css-architecture.md

Game frontend CSS architecture

The game frontend preserves the rendered contract of ref/sam; CSS reuse is not a reason to normalize a page's width, height, typography, texture, or interaction states. When reuse and the reference geometry conflict, the reference geometry wins.

Layers

app/game-frontend/src/assets/main.css is the single global entry point. It loads the following layers:

1. styles/tokens.css: exact shared font, color, and /image/game texture values. These are value aliases only and must resolve to the same computed value as the ref page.
2. styles/game-shell.css: the flexible shell shared by the main dashboard, public dashboard, and chief center. Only declarations proven identical across those screens belong here.
3. styles/ref-shell.css: fixed ref geometry, including the 1000px desktop / 500px mobile family used by the battle center. Its namespace stays separate from the flexible shell so a generic responsive rule cannot override it.
4. Scoped SFC styles: page-specific grids, fixed table dimensions, selectors, and state styling. These remain closest to the DOM contract they implement.

styles/legacy-controls.css is the shared control layer between tokens and the two shell layers. It owns only control geometry and state rules that are proven identical in the Ref Bootstrap/Lumen family. A page still owns control width, grid placement, and any visual family that is not Bootstrap/Lumen.

Button composition

Choose the Ref visual family before choosing a semantic color. Buttons from different historical families are not made identical merely because they have the same label.

Ref family	Core composition	Use
Bootstrap/Lumen primary	.legacy-button.legacy-button--primary	commit, purchase, submit, or another affirmative mutation
Bootstrap/Lumen secondary	.legacy-button.legacy-button--secondary	reset, cancel, neutral toggle, or load-more
Bootstrap/Lumen danger	.legacy-button.legacy-button--danger	destructive action only when Ref uses variant="danger"
Bootstrap/Lumen info	.legacy-button.legacy-button--info	informational or edit action only when Ref uses variant="info"
btn-sammo-base2 navigation	.legacy-button.legacy-button--navigation	page back/close and paired reload controls
page-specific/native control	feature-namespaced scoped class	only when Ref computed geometry or interaction differs from the Bootstrap/Lumen family

The base class supplies accessible link/button normalization and the historical base1 fallback used by already measured screens. New Bootstrap/Lumen controls must add an explicit semantic modifier; do not infer a mutation role from a label such as 구입 in page CSS. A disabled control keeps its semantic color and uses the shared opacity/cursor state. Hover and active use the Ref Lumen bottom-border movement rather than an unrelated brightness filter.

Only layout belongs in the SFC: width, grid column, margins required by the page, and breakpoint-specific placement. Color, border, font weight, hover/focus/active, and disabled presentation belong in legacy-controls.css when the Ref family is shared. Generic .btn, button, or .primary rules must not be promoted globally.

Class naming

• .game-shell, .game-shell__header, .game-shell__actions: flexible application shell.
• .ref-shell, .ref-shell__topbar, .ref-shell__control: measured legacy shell and controls.
• .game-feedback--error, .ref-feedback--error: feedback scoped to its visual family.
• Feature-specific classes stay namespaced by their feature or component. Generic names such as .title, .error, .ghost, .stack, and .layout-grid must not be promoted from a scoped SFC merely because the same spelling appears elsewhere.

Feature hooks stay inside their owning component. Shared presentation uses one of the explicit shell namespaces.

Consolidation rule

Before moving declarations out of an SFC:

1. Compare every same-named selector's declarations and semantic role.
2. Confirm the affected pages use the same layout family.
3. Record desktop and mobile getBoundingClientRect() and getComputedStyle() values before the move.
4. Move only identical declarations; keep exceptions in the owning SFC.
5. Re-run Chromium geometry plus hover, focus, active, and disabled states.

The main page and chief center are the flexible-shell references. The battle center is the fixed ref-shell reference. If another page has a measured ref contract that differs from both, preserve that page's local contract rather than forcing it into either family.

Asset boundary

The CSS variables contain /image/game/* URLs but do not import or copy image files. Caddy continues to own /image/*; Vite must not rewrite the image tree as application assets.