.practice-page main {max-width:1060px;margin:22px auto;padding:0 16px;}
.practice-page .card {margin-bottom:18px;}
.quiz-prompt,.quiz-material,.quiz-explanation {font-size:18px;line-height:1.9;overflow-wrap:anywhere;}
.quiz-prompt p,.quiz-material p,.quiz-explanation p {margin:10px 0;}
.quiz-prompt img,.quiz-material img,.quiz-explanation img,.quiz-option img {max-width:100%;height:auto;vertical-align:middle;}
.quiz-material {background:var(--surface);padding:16px;border:1px solid var(--line);border-radius:12px;margin:18px 0;}
.quiz-options {display:grid;gap:12px;margin:22px 0;}
.quiz-option {display:flex;align-items:flex-start;text-align:left;gap:14px;min-height:60px;padding:16px;border:1px solid var(--line);background:var(--panel);color:var(--text);font-size:17px;line-height:1.65;width:100%;}
.quiz-option:hover:not(:disabled) {border-color:var(--blue);background:var(--blue-soft);}
.quiz-option.selected {border-color:var(--blue);background:var(--blue-soft);}
.quiz-option.correct {border-color:var(--teal);background:var(--teal-soft,#edf7f4);}
.quiz-option.wrong {border-color:var(--brand);background:var(--brand-soft,#fff0f0);}
.quiz-option:disabled {opacity:1;cursor:default;}
.quiz-option-key {display:grid;place-items:center;flex:0 0 34px;height:34px;border:1px solid currentColor;border-radius:9px;font-weight:700;}
.quiz-option-body {min-width:0;flex:1;}
.quiz-option-body p {margin:0;}
.quiz-feedback {border-left:4px solid var(--teal);padding:16px 18px;background:var(--surface);border-radius:10px;margin:18px 0;}
.quiz-feedback.wrong {border-color:var(--brand);}
.quiz-actions {display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-top:18px;}
.quiz-questions {display:flex;flex-wrap:wrap;gap:6px;max-height:160px;overflow:auto;}
.quiz-questions button {min-width:42px;min-height:42px;padding:5px;}
.quiz-questions button[aria-current=true] {outline:2px solid var(--blue);outline-offset:1px;}
.quiz-questions .correct {background:var(--teal-soft,#edf7f4);color:var(--teal);}
.quiz-questions .wrong {background:var(--brand-soft,#fff0f0);color:var(--brand);}
.quiz-stats {display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:12px;margin:15px 0;}
.quiz-stats strong {display:block;font-size:25px;color:var(--text);}
.quiz-top {display:flex;justify-content:space-between;gap:12px;align-items:center;flex-wrap:wrap;}
.quiz-timer {font-variant-numeric:tabular-nums;}
.quiz-history .docrow {display:flex;justify-content:space-between;gap:12px;align-items:center;flex-wrap:wrap;}
.quiz-error-history {border-left:3px solid var(--brand);padding-left:12px;}
#practiceToast {position:fixed;bottom:20px;left:50%;transform:translateX(-50%);max-width:90%;padding:12px 18px;background:var(--header);color:white;border-radius:10px;z-index:20;}
@media(max-width:600px){.practice-page main{padding:0 10px;margin-top:12px;}.quiz-prompt,.quiz-material,.quiz-explanation{font-size:17px;}.quiz-option{padding:12px;font-size:16px;gap:10px;}.quiz-stats{grid-template-columns:repeat(3,minmax(0,1fr));}.quiz-stats strong{font-size:23px;}.quiz-actions button,.quiz-actions a{min-height:44px;}.quiz-material{padding:10px;}.practice-page header .brand{font-size:16px;}}
/* u1: temporary scratch layer is isolated from saved document annotation records. */
.quiz-ink-card {position:relative;}
.quiz-scratch {position:absolute;left:0;top:0;z-index:3;pointer-events:none;touch-action:none;user-select:none;}
.quiz-ink-tools {position:sticky;top:0;z-index:4;display:flex;align-items:center;gap:7px;flex-wrap:wrap;background:var(--panel);padding:6px 0;margin:0 0 12px;border-bottom:1px solid var(--line);}
.quiz-ink-tools button {padding:6px 10px;min-height:36px;font-size:13px;}
.quiz-ink-tools [aria-pressed=true] {background:var(--blue-soft);border-color:var(--blue);color:var(--blue);}
.quiz-ink-tools label {display:flex;align-items:center;gap:5px;font-size:12px;margin:0;}
.quiz-ink-tools input[type=color] {width:34px;height:32px;min-height:0;padding:2px;}
.quiz-ink-tools input[type=range] {width:75px;min-height:32px;padding:0;}
.quiz-metadata {margin:8px 0 12px;font-size:13px;}.quiz-metadata>summary {cursor:pointer;color:var(--muted);padding:6px 0;}
.quiz-metadata p {margin:6px 0;}.quiz-prompt {margin:12px 0;font-size:19px;line-height:1.7;}
.quiz-prompt img,.quiz-explanation img,.quiz-option-body img {max-width:100%;height:auto;}
.quiz-prompt .quiz-formula,.quiz-option-body .quiz-formula,.quiz-explanation .quiz-formula {display:inline-block;vertical-align:middle;width:auto;max-height:3em;}
.practice-page .quiz-option.correct {color:#17563f;}.practice-page .quiz-option.wrong {color:#9b2432;}
@media(orientation:landscape) and (max-height:850px){.practice-page header{padding:8px 18px;}.practice-page header .brand{font-size:18px;}.practice-page main{margin-top:12px;}.practice-page .card{padding:18px;}.quiz-top h1{font-size:21px;}.quiz-option{padding:12px;}.quiz-ink-tools{margin-bottom:8px;}}
@media(max-width:600px){.quiz-ink-tools{gap:5px;}.quiz-ink-tools>span.small{display:none;}.quiz-prompt{font-size:17px;}}
.practice-page header {padding:8px 18px;min-height:58px;}
.practice-page header .brand {font-size:17px;line-height:1.3;}
.practice-page header .brand::before {width:34px;height:34px;top:0;font-size:23px;}
.practice-page header a.button {min-height:36px;padding:6px 10px;}
.practice-page header .subtitle {font-size:11px;}
.practice-page main>.quiz-top {margin:0 0 8px;}
.practice-page main>.quiz-top h1 {margin:0;font-size:21px;}
.quiz-compact-knowledge {margin:8px 0;font-size:13px;}
.quiz-ink-card>.quiz-top {gap:6px;}.quiz-ink-card progress {display:block;height:6px;margin:8px 0;width:100%;}
.quiz-ink-card>.quiz-metadata {margin:5px 0;}
.quiz-metadata summary {background:transparent!important;}
.quiz-ink-card>.quiz-prompt {margin-top:10px;}
.quiz-ink-card>.quiz-options {margin:14px 0;gap:9px;}
@media(orientation:landscape) and (max-height:850px){.quiz-ink-card>.quiz-option{min-height:48px;}.practice-page header{position:static;}.quiz-ink-tools>span.small{display:none;}}
.quiz-collect-quick {padding:4px 8px;min-height:28px;font-size:12px;float:right;margin:0 0 5px 8px;}
.quiz-prompt {clear:both;}

/* n1: keep the tool dock visible above the header while the page is frozen. */
.quiz-ink-tools{top:var(--quiz-tools-top,0px);z-index:30;isolation:isolate;max-width:100%;}
.quiz-ink-docked{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:7px 9px;box-shadow:0 4px 18px #0003;}
.quiz-ink-tools button,.quiz-ink-tools label{flex-shrink:0;white-space:nowrap;}
.quiz-ink-spacer{pointer-events:none;}
@media(max-width:600px){.quiz-ink-title{display:none;}.quiz-ink-tools button{padding:6px 7px;}.quiz-ink-tools [data-lock-status]{display:block;flex-basis:100%;font-size:11px;}.quiz-ink-tools [type=range]{width:65px;}}