:root{--bg:#0e1016;--panel:#161922;--line:#262a37;--fg:#e6e8ef;--dim:#8b90a3;--acc:#6c7bff;--acc2:#a56cff;--tabs-h:38px}
*{box-sizing:border-box}
html,body{margin:0;height:100%;background:var(--bg);color:var(--fg);font:13px/1.4 system-ui,-apple-system,"Hiragino Sans","Yu Gothic UI",sans-serif;overflow:hidden;overscroll-behavior:none}
#app{display:flex;flex-direction:column;height:100dvh;height:100svh;height:100dvh}
#tabs{display:flex;align-items:center;gap:2px;padding:0 8px;height:var(--tabs-h);background:var(--panel);border-bottom:1px solid var(--line);flex:none}
.brand{display:flex;align-items:center;gap:6px;margin-right:10px;white-space:nowrap}
.logo{display:inline-grid;place-items:center;width:22px;height:22px;border-radius:6px;background:linear-gradient(135deg,var(--acc),var(--acc2));color:#fff;font-size:13px}
.spacer{flex:1}
#tabs button{all:unset;box-sizing:border-box;display:flex;align-items:center;gap:6px;padding:0 12px;height:30px;border-radius:7px;color:var(--dim);cursor:pointer;white-space:nowrap}
#tabs button:hover{background:#1e2230;color:var(--fg)}
#tabs button:focus-visible{outline:2px solid var(--acc)}
#tabs .tab[aria-selected=true]{background:linear-gradient(135deg,#2a3070,#3b2a70);color:#fff}
#tabs i{font-style:normal}
kbd{font:11px ui-monospace,Menlo,Consolas,monospace;background:#20243200;border:1px solid var(--line);border-radius:4px;padding:0 4px;color:var(--dim)}
#tabs .tab kbd{margin-left:2px}
#stage{position:relative;flex:1;min-height:0}
#stage iframe{position:absolute;inset:0;width:100%;height:100%;border:0;background:var(--bg);display:none}
#stage iframe.on{display:block}
#loading{position:absolute;inset:0;display:grid;place-items:center;color:var(--dim);pointer-events:none;opacity:0;transition:opacity .2s}
#loading.show{opacity:1}
#btnTouch[data-mode=scroll]{color:#ffd166}
/* ヘルプ */
#help[hidden]{display:none}
#help{position:fixed;inset:0;z-index:50;background:#000a;display:grid;place-items:center;padding:12px}
.sheet{width:min(720px,100%);max-height:100%;overflow:auto;background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:14px 16px}
.sheet header{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px;font-size:15px}
.sheet header button{all:unset;cursor:pointer;padding:4px 10px;border-radius:6px}
.sheet header button:hover{background:#2a2f40}
.sheet h3{margin:12px 0 4px;font-size:12px;color:var(--acc);letter-spacing:.05em}
.sheet section.cur h3::after{content:" ← 現在のモード";color:#ffd166}
dl{display:grid;grid-template-columns:max-content 1fr;gap:4px 14px;margin:0}
dt{white-space:nowrap}dd{margin:0;color:var(--dim)}
.note{color:var(--dim);font-size:12px;margin:12px 0 2px}
/* スマホ: タブを下に */
@media (max-width:900px){
  #app{flex-direction:column-reverse}
  #tabs{height:auto;min-height:54px;padding:4px 6px calc(4px + env(safe-area-inset-bottom));border-bottom:0;border-top:1px solid var(--line);justify-content:space-between}
  .brand,.spacer,#tabs kbd{display:none}
  #tabs button{flex:1 1 0;flex-direction:column;justify-content:center;gap:1px;height:46px;padding:0 2px;font-size:10px;border-radius:9px}
  #tabs button i{font-size:18px;line-height:1}
  #btnFull{display:none}
  dl{grid-template-columns:1fr}dt{margin-top:4px}
}
@media (display-mode:standalone){#btnFull{display:none}}