/* チャッピーGameセンター 共通スタイル（トップ・規約・先生用） */
:root{--ink:#24364d;--sub:#64788f;--sky:#45bdfb;--apple:#ef4b4b;--sun:#ffd84a;--leaf:#3cc47c;color-scheme:light}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:"M PLUS Rounded 1c",system-ui,-apple-system,"Hiragino Maru Gothic ProN",sans-serif;color:var(--ink);background:#f4fbff}
a{color:#1b88c9}
button{font-family:inherit}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;border:0;border-radius:999px;padding:11px 16px;font:900 15px/1.1 "M PLUS Rounded 1c",sans-serif;
  color:#fff;background:var(--sky);box-shadow:0 5px 0 #1d8fd1;cursor:pointer;text-decoration:none;transition:transform .08s,box-shadow .08s;white-space:nowrap}
.btn:active{transform:translateY(3px);box-shadow:0 2px 0 #1d8fd1}
.btn.sm{padding:8px 14px;font-size:13px;box-shadow:0 3px 0 #1d8fd1}
.btn.big{padding:16px 22px;font-size:18px}
.btn.red{background:#ef4b4b;box-shadow:0 5px 0 #b8302d}
.btn.gray{background:#93a3b5;box-shadow:0 5px 0 #6e7f92}
.btn.green{background:#3cc47c;box-shadow:0 5px 0 #23935a}
.btn:disabled{opacity:.5;cursor:not-allowed}

.modal{position:fixed;inset:0;z-index:50;background:rgba(10,40,70,.5);display:flex;justify-content:center;align-items:flex-start;overflow-y:auto;padding:24px 16px;
  -webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);animation:fadeIn .2s}
.modal[hidden]{display:none}
@keyframes fadeIn{from{opacity:0}}
.sheet{--c:#45bdfb;--c2:#cdeeff;position:relative;width:100%;max-width:460px;background:#fff;border-radius:28px;padding:22px 18px;margin:auto 0;
  box-shadow:0 10px 0 var(--c),0 24px 50px rgba(0,0,0,.25);animation:popIn .35s cubic-bezier(.2,1.5,.4,1)}
@keyframes popIn{from{transform:scale(.85) translateY(20px);opacity:0}}
.sheet .x{position:absolute;top:10px;right:10px;width:38px;height:38px;border-radius:50%;border:0;background:#eef3f8;font-size:22px;font-weight:900;color:var(--sub);cursor:pointer;z-index:2}