:root{--blue: #2b7fd8;--yellow: #f4d758;--red: #e84a5f;--cream: #fefcf6;--cream-deep: #faf6eb;--ink: #1a1a2e;--ink-light: #4a4a5a;--ink-faint: #85858f;--card: #fffefa;font-family:Noto Sans SC,Microsoft YaHei,PingFang SC,system-ui,sans-serif;color:var(--ink);background:var(--cream)}*{box-sizing:border-box}html,body,#app{min-height:100%;margin:0}body{margin:0;background:var(--cream);overflow:hidden}button,input,select{font:inherit}button,summary{color:inherit}button{cursor:pointer}summary{list-style:none;cursor:pointer}summary::-webkit-details-marker{display:none}::selection{background:var(--yellow);color:var(--ink)}.design-credit-marker{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}.student-only{display:none}#app[data-mode=student] .teacher-only{display:none!important}#app[data-mode=student] .student-only{display:inline-flex}.app-header{height:56px;padding:0 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