header{align-items:center;flex-wrap:wrap}.display-settings{display:flex;align-items:center;gap:12px;font-size:14px}.display-settings label{margin:0;color:white}.display-settings select{margin:0;min-height:40px;width:auto;font-size:14px}.display-settings button{min-height:40px;font-size:14px;padding:6px 10px}.language-note{max-width:1400px;margin:0 auto;padding:10px 5%;font-size:14px;color:#53677b;border-bottom:1px solid #dce5ed}.language-note:empty{display:none}
.focus-nav{position:sticky;top:0;z-index:20;display:flex;align-items:center;flex-wrap:wrap;gap:8px;background:#f2f6faf5;padding:10px 0;border-bottom:1px solid #dce5ed;backdrop-filter:blur(8px)}.focus-nav button{font-size:14px;min-height:44px}.focus-position{font-size:14px;color:#53677b;margin-right:auto}.focus-heading h1{font-size:25px}.focus-heading #question-meta{margin-top:0}.focus-question,.focus-help{min-width:0;scroll-margin-top:100px}.focus-help>h2{margin-top:0}.focus-help>.learning-panel{margin:14px 0}.focus-question>.notice{margin-top:0}.focus-question a{overflow-wrap:anywhere}.focus-help #reveal{width:100%}.focus-help #answer-panel{scroll-margin-top:100px}.focus-help .solution{padding:16px}.focus-help .learning-nav{gap:8px}.focus-help .page-reader-controls{gap:7px}.focus-help .page-reader-controls button{font-size:14px}.focus-help .pilot-step{grid-template-columns:minmax(0,1fr) auto}.focus-help #answer-panel>h2{font-size:22px}.focus-help .choices{flex-wrap:wrap}
@media(min-width:1000px) and (orientation:landscape){.practice-open main{max-width:1600px;padding-left:3%;padding-right:3%}.focus-enabled .focus-layout{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(340px,1fr);align-items:start;gap:24px}.focus-enabled .focus-question{position:sticky;top:88px;max-height:calc(100vh - 110px);max-height:calc(100dvh - 110px);overflow:auto;overscroll-behavior:contain;padding-right:12px}.focus-enabled .focus-help{border-left:1px solid #dce5ed;padding-left:24px}.focus-question .page-reader-controls button{font-size:14px;padding:7px 10px}.focus-enabled .focus-question .page-reader-viewport{overflow:auto}}
@media(max-width:999px),(orientation:portrait){.focus-layout{display:block}.focus-help{margin-top:24px}.focus-nav{gap:6px}.focus-nav button{padding:7px 9px}.focus-nav .focus-position{flex-basis:100%;order:-1}.focus-heading h1{font-size:22px}.focus-question,.focus-help,.focus-help #answer-panel{scroll-margin-top:155px}.display-settings{flex-wrap:wrap}.display-settings select{max-width:100%}}
body[data-display-language=zh] .pilot-english{display:none!important}body[data-display-language=en] .card-topic-en{display:block}
.translation-pending:after{content:attr(data-translation-note);display:block;font-size:12px;font-weight:400;line-height:1.5;color:#657287;margin-top:5px}.translation-pending:empty:after{display:none}.math-notation{display:inline-block;max-width:100%;vertical-align:middle;overflow-x:auto;overflow-y:hidden;padding:3px 2px}.math-notation math{font-size:1.12em;white-space:nowrap}.study-formula{line-height:2}.original-notation{font-family:ui-monospace,monospace;white-space:pre-wrap}.focus-help p,.focus-help li{overflow-wrap:anywhere}
@media(prefers-reduced-motion:reduce){.focus-question,.focus-help{scroll-behavior:auto!important}}
body[data-display-language=zh] .card-topic-en{display:none}.focus-question,.focus-help,.focus-help #answer-panel{scroll-margin-top:calc(var(--focus-nav-height,100px) + 18px)}
@media(min-width:1000px) and (orientation:landscape){.focus-enabled .focus-question{top:calc(var(--focus-nav-height,76px) + 12px);max-height:calc(100vh - var(--focus-nav-height,76px) - 24px);max-height:calc(100dvh - var(--focus-nav-height,76px) - 24px)}}
@media(max-width:999px),(orientation:portrait){.focus-mode-toggle{display:none}.focus-nav button{flex-grow:1}.focus-position{font-size:13px}}
.language-settings-note{padding:5px 5%;border-bottom:1px solid #dce5ed;color:#53677b;font-size:14px}.language-settings-note summary{font-size:14px;font-weight:500;min-height:32px}.language-settings-note .language-note{padding:6px 0;border:0}.language-settings-note[open]>summary{margin-bottom:0}
.focus-session-bar.learning-panel{padding:12px 16px;margin:12px 0}.focus-session-bar p{font-size:14px;margin:0 0 8px}.focus-session-bar progress{display:block;margin:8px 0}.focus-redundant-skip{display:none}.focus-session-bar button{font-size:14px}
@media(max-width:600px){header{align-items:flex-start}.display-settings{width:100%;flex-wrap:nowrap}.display-settings label{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}.display-settings select{max-width:120px}.display-settings button{white-space:normal}.focus-nav{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));align-items:stretch}.focus-position{grid-column:1/-1}.focus-nav button{min-width:0}.focus-nav #back{font-size:13px}}