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--tw-sepia{syntax:"*";inherits:false}@property --tw-drop-shadow{syntax:"*";inherits:false}@property --tw-drop-shadow-color{syntax:"*";inherits:false}@property --tw-drop-shadow-alpha{syntax:"<percentage>";inherits:false;initial-value:100%}@property --tw-drop-shadow-size{syntax:"*";inherits:false}
.editor{background:var(--surface);border:1px solid var(--line);border-radius:10px;min-height:60px;position:relative;overflow:hidden}.editor:focus-within{border-color:color-mix(in srgb, var(--link) 55%, var(--line))}.editor-highlight,.editor-input{font-family:var(--font-mono);tab-size:2;white-space:pre;letter-spacing:0;border:none;width:100%;height:100%;margin:0;padding:14px 16px;font-size:13.5px;line-height:21.87px;overflow:auto}.editor-highlight{pointer-events:none;color:var(--ink);position:absolute;inset:0}.editor-highlight code{font:inherit;background:0 0;border:none;padding:0}.editor-input{color:#0000;caret-color:var(--accent);resize:none;background:0 0;outline:none;position:relative}.editor-input::selection{background:color-mix(in srgb, var(--link) 35%, transparent)}.runner{border:1px solid var(--line);background:var(--surface);border-radius:12px;margin:20px 0;overflow:hidden}.runner-head{border-bottom:1px solid var(--line);background:var(--raised);color:var(--faint);align-items:center;gap:10px;padding:8px 12px;font-size:12px;font-weight:560;display:flex}.runner-head .spacer{flex:1}.runner .editor{background:var(--surface);border:none;border-radius:0}.runner-body{gap:0;display:grid}.runner-body.split{grid-template-columns:minmax(0,1fr) auto}@media (max-width:860px){.runner-body.split{grid-template-columns:minmax(0,1fr)}}.runner-preview{border-left:1px solid var(--line);background:var(--raised);justify-content:center;align-items:center;padding:18px;display:flex}@media (max-width:860px){.runner-preview{border-left:none;border-top:1px solid var(--line)}}.console{border-top:1px solid var(--line);background:color-mix(in srgb, var(--bg) 70%, var(--surface));font-family:var(--font-mono);white-space:pre-wrap;word-break:break-word;max-height:260px;color:var(--dim);padding:11px 16px;font-size:12.8px;line-height:1.6;overflow:auto}.console.empty{color:var(--faint);font-style:italic}.console.error{color:var(--bad);border-top-color:color-mix(in srgb, var(--bad) 40%, var(--line))}.console-label{font-family:var(--font-sans);letter-spacing:.09em;text-transform:uppercase;color:var(--faint);margin-bottom:5px;font-size:10.5px;font-weight:620;display:block}.exercise{border:1px solid var(--line-strong);background:var(--surface);border-radius:14px;margin:26px 0;overflow:hidden}.exercise.passed{border-color:color-mix(in srgb, var(--good) 50%, var(--line))}.exercise-head{border-bottom:1px solid var(--line);background:linear-gradient(180deg, var(--raised), var(--surface));align-items:flex-start;gap:10px;padding:13px 16px;display:flex}.exercise-head h4{letter-spacing:-.01em;margin:0;font-size:15px;font-weight:640}.exercise-prompt{padding:4px 16px 12px;font-size:15px}.exercise-prompt>:first-child{margin-top:0}.exercise-actions{border-top:1px solid var(--line);background:var(--raised);flex-wrap:wrap;align-items:center;gap:8px;padding:12px 16px;display:flex}.exercise-actions .spacer{flex:1}.feedback{border-top:1px solid var(--line);flex-direction:column;gap:8px;padding:12px 16px;font-size:14px;display:flex}.feedback-item{align-items:flex-start;gap:9px;line-height:1.55;display:flex}.feedback-item pre{font-family:var(--font-mono);white-space:pre-wrap;color:var(--dim);margin:4px 0 0;font-size:12.5px}.feedback-icon{border-radius:50%;flex:none;place-items:center;width:17px;height:17px;margin-top:2px;font-size:11px;font-weight:700;display:grid}.feedback-icon.pass{background:color-mix(in srgb, var(--good) 22%, transparent);color:var(--good)}.feedback-icon.fail{background:color-mix(in srgb, var(--bad) 22%, transparent);color:var(--bad)}.feedback-icon.info{background:var(--raised);color:var(--faint)}.hint{border-left:2px solid var(--warn);background:color-mix(in srgb, var(--warn) 7%, transparent);color:var(--dim);border-radius:0 8px 8px 0;padding:9px 13px;font-size:14px}.diff-grid{border-top:1px solid var(--line);background:var(--raised);flex-wrap:wrap;justify-content:center;gap:22px;padding:16px;display:flex}
.quiz-card{border:1px solid var(--line-strong);background:var(--surface);max-width:var(--measure);border-radius:14px;flex-direction:column;gap:12px;margin:26px 0;padding:16px 18px;display:flex}.quiz-card header{flex-wrap:wrap;align-items:center;gap:10px;display:flex}.quiz-card.pretest{border-color:color-mix(in srgb, var(--accent) 40%, var(--line));background:linear-gradient(180deg, var(--accent-soft), transparent 60%), var(--surface)}.quiz-card.predict{border-color:color-mix(in srgb, var(--violet) 35%, var(--line))}.quiz-card.generative{border-color:color-mix(in srgb, var(--mint) 32%, var(--line))}.quiz-card .prose>:first-child{margin-top:0}.quiz-card .btn{align-self:flex-start}.choices{flex-direction:column;gap:7px;display:flex}.choice{text-align:left;border:1px solid var(--line);background:var(--raised);color:var(--ink);font:inherit;cursor:pointer;border-radius:10px;align-items:flex-start;gap:11px;padding:10px 13px;font-size:14.8px;line-height:1.5;transition:border-color .14s,background .14s;display:flex}.choice:hover:not(:disabled){border-color:var(--faint)}.choice:disabled{cursor:default}.choice code{font-family:var(--font-mono);background:var(--bg);border:1px solid var(--line);border-radius:5px;padding:.08em .35em;font-size:.86em}.choice-marker{background:var(--bg);border:1px solid var(--line);width:21px;height:21px;color:var(--faint);border-radius:6px;flex:none;place-items:center;margin-top:1px;font-size:11.5px;font-weight:640;display:grid}.choice.selected{border-color:var(--link);background:var(--link-soft)}.choice.selected .choice-marker{background:var(--link);border-color:var(--link);color:#061019}.choice.correct{border-color:color-mix(in srgb, var(--good) 60%, var(--line));background:color-mix(in srgb, var(--good) 9%, transparent)}.choice.correct .choice-marker{background:var(--good);border-color:var(--good);color:#04150d}.choice.wrong{border-color:color-mix(in srgb, var(--bad) 55%, var(--line));background:color-mix(in srgb, var(--bad) 8%, transparent)}.choice.wrong .choice-marker{background:var(--bad);border-color:var(--bad);color:#1a0508}.reveal{border-top:1px solid var(--line);padding-top:12px;font-size:14.8px}.reveal>:first-child{margin-top:0}.guess-input{background:var(--bg);border:1px solid var(--line);width:100%;color:var(--ink);font-family:var(--font-mono);resize:vertical;border-radius:9px;padding:10px 12px;font-size:13px;line-height:1.6}.guess-input:focus{border-color:var(--link);outline:none}.predict-compare{grid-template-columns:1fr 1fr;gap:14px;display:grid}@media (max-width:600px){.predict-compare{grid-template-columns:1fr}}.predict-compare pre{background:var(--bg);border:1px solid var(--line);font-family:var(--font-mono);white-space:pre-wrap;border-radius:8px;min-height:42px;margin:0;padding:9px 11px;font-size:12.5px}.callout{border:1px solid var(--line);border-left:3px solid var(--callout,var(--link));background:color-mix(in srgb, var(--callout,var(--link)) 6%, var(--surface));max-width:var(--measure);border-radius:0 11px 11px 0;margin:22px 0;padding:13px 16px}.callout-label{letter-spacing:.07em;text-transform:uppercase;color:var(--callout,var(--link));margin-bottom:5px;font-size:11.5px;font-weight:680}.callout .prose>:first-child{margin-top:0}.callout .prose>:last-child{margin-bottom:0}.callout.xcode{border-left-width:3px;border-radius:11px}.compare{margin:24px 0}.compare-grid{grid-template-columns:1fr 1fr;gap:14px;display:grid}@media (max-width:780px){.compare-grid{grid-template-columns:1fr}}.compare-title{letter-spacing:.07em;text-transform:uppercase;color:var(--faint);margin-bottom:6px;font-size:11.5px;font-weight:680}.compare-note{color:var(--dim);margin-top:12px;font-size:14.5px}.confidence{margin-top:6px}.confidence-row{flex-wrap:wrap;gap:7px;display:flex}.confidence-button{border:1px solid var(--line);background:var(--raised);min-width:84px;color:var(--dim);font:inherit;cursor:pointer;border-radius:10px;flex-direction:column;flex:1;align-items:center;gap:2px;padding:9px 6px;transition:all .14s;display:flex}.confidence-button span{font-size:15px;font-weight:640}.confidence-button small{text-align:center;font-size:10.5px;line-height:1.25}.confidence-button:hover{border-color:var(--faint)}.confidence-button.active{border-color:var(--accent);background:var(--accent-soft);color:var(--accent)}
.phone-wrap{flex-direction:column;align-items:center;gap:8px;display:flex}.phone{--phone-bg:#000208;--phone-ink:#f2f4f8;--phone-ink-dim:#9aa3b5;--phone-ink-faint:#6a7285;--phone-line:#2b3240;--phone-fill:#1c2230;background:linear-gradient(160deg,#3a4152,#1a1f2b 45%,#262c3a);border-radius:38px;flex:none;width:268px;height:540px;padding:9px;position:relative;box-shadow:0 0 0 1px #ffffff14,0 22px 48px #00000073}.phone.compact{width:232px;height:452px}.phone-notch{z-index:5;background:#000;border-radius:999px;width:78px;height:21px;position:absolute;top:15px;left:50%;transform:translate(-50%)}.phone-screen{background:var(--phone-bg);width:100%;height:100%;color:var(--phone-ink);font-family:var(--font-sans);border-radius:30px;flex-direction:column;justify-content:center;align-items:center;gap:8px;padding:44px 16px 22px;font-size:17px;line-height:1.35;display:flex;overflow:auto}.phone-screen>*{max-width:100%}.phone-label{color:var(--faint);letter-spacing:.02em;font-size:12px;font-weight:560}.sui-divider{background:var(--phone-line);width:100%;height:1px;margin:2px 0}.sui-scroll{flex-direction:column;gap:8px;width:100%;max-height:100%;display:flex;overflow:auto}.sui-list{background:var(--phone-fill);border-radius:12px;width:100%;overflow:hidden}.sui-row{border-bottom:1px solid var(--phone-line);padding:11px 14px;font-size:16px}.sui-row:last-child{border-bottom:none}.sui-navlink{justify-content:space-between;align-items:center;gap:10px;width:100%;display:flex}.sui-chevron{color:var(--phone-ink-faint);font-size:18px}.sui-button{color:#0a84ff;cursor:default;justify-content:center;align-items:center;gap:6px;font-size:17px;font-weight:500;display:inline-flex}.sui-control{justify-content:space-between;align-items:center;gap:12px;width:100%;display:flex}.sui-switch{background:#3a4152;border-radius:999px;flex:none;width:44px;height:26px;position:relative}.sui-switch:after{content:"";background:#fff;border-radius:50%;width:22px;height:22px;transition:transform .2s;position:absolute;top:2px;left:2px}.sui-switch.on{background:#32d74b}.sui-switch.on:after{transform:translate(18px)}.sui-field{background:var(--phone-fill);width:100%;color:var(--phone-ink-faint);border-radius:9px;padding:9px 12px;font-size:16px}.sui-slider{background:var(--phone-line);border-radius:999px;width:100%;height:4px;position:relative}.sui-slider span{background:#fff;border-radius:50%;width:20px;height:20px;position:absolute;top:-8px;left:40%;box-shadow:0 1px 3px #0006}.sui-progress{background:var(--phone-line);border-radius:999px;width:100%;height:4px;overflow:hidden}.sui-progress span{background:#0a84ff;height:100%;display:block}.sui-shape{background:currentColor;width:100%;min-width:24px;height:100%;min-height:24px}.sui-symbol{border:1px dashed var(--phone-line);color:var(--phone-ink-faint);font-size:11px;font-family:var(--font-mono);border-radius:5px;padding:1px 6px;display:inline-block}.sui-custom{display:contents}.sui-unknown{border:1px dashed var(--phone-line);color:var(--phone-ink-faint);font-size:12px;font-family:var(--font-mono);border-radius:8px;padding:6px 10px}.sui-annotation{font-size:10.5px;font-family:var(--font-mono);color:var(--phone-ink-faint);border-bottom:1px solid var(--phone-line);text-align:center;margin-bottom:6px;padding-bottom:3px}.sui-tabview{flex-direction:column;justify-content:space-between;width:100%;height:100%;display:flex}.sui-tabcontent{flex:1;justify-content:center;align-items:center;display:flex}.sui-tabbar{border-top:1px solid var(--phone-line);color:var(--phone-ink-faint);justify-content:space-around;padding-top:8px;font-size:10px;display:flex}.sui-tabbar .active{color:#0a84ff}
.site-header{z-index:40;background:color-mix(in srgb, var(--bg) 82%, transparent);-webkit-backdrop-filter:saturate(160%)blur(14px);border-bottom:1px solid var(--line);position:sticky;top:0}.site-header-inner{align-items:center;gap:22px;height:54px;display:flex}.brand{color:var(--ink);flex:none;align-items:center;gap:9px;text-decoration:none;display:inline-flex}.brand-mark{fill:none;width:25px;height:25px;stroke:var(--accent);stroke-width:1.7px;stroke-linecap:round;stroke-linejoin:round}.brand-text{letter-spacing:-.025em;font-size:15.5px;font-weight:680}.brand-text span{color:var(--faint);font-weight:500}.site-header nav{scrollbar-width:none;flex:1;gap:2px;display:flex;overflow-x:auto}.site-header nav::-webkit-scrollbar{display:none}.site-header nav a{color:var(--dim);white-space:nowrap;border-radius:8px;align-items:center;gap:6px;padding:5px 11px;font-size:14px;font-weight:540;text-decoration:none;display:inline-flex}.site-header nav a:hover{background:var(--raised);color:var(--ink)}.site-header nav a.active{color:var(--ink);background:var(--raised)}.badge{background:var(--accent);color:#14100c;border-radius:999px;place-items:center;min-width:18px;height:18px;padding:0 5px;font-size:11px;font-weight:700;display:grid}.theme-toggle{border:1px solid var(--line);background:var(--raised);width:30px;height:30px;color:var(--dim);cursor:pointer;border-radius:8px;flex:none;place-items:center;font-size:15px;display:grid}.theme-toggle:hover{color:var(--ink);border-color:var(--faint)}.site-footer{border-top:1px solid var(--line);color:var(--faint);margin-top:72px;padding:22px 0 44px;font-size:13px}.site-footer .shell{flex-wrap:wrap;justify-content:space-between;gap:16px;display:flex}.page{padding:34px 0 0}.page-title{letter-spacing:-.028em;margin:0 0 8px;font-size:clamp(26px,4.2vw,38px);font-weight:700;line-height:1.1}.page-lead{color:var(--dim);max-width:62ch;margin:0 0 26px;font-size:16.5px}.eyebrow{letter-spacing:.11em;text-transform:uppercase;color:var(--accent);margin-bottom:10px;font-size:11.5px;font-weight:680}.section-title{letter-spacing:.07em;text-transform:uppercase;color:var(--faint);margin:40px 0 14px;font-size:13px;font-weight:660}.grid-cards{grid-template-columns:repeat(auto-fill,minmax(268px,1fr));gap:14px;display:grid}.stat-row{grid-template-columns:repeat(auto-fit,minmax(132px,1fr));gap:12px;display:grid}.stat{border:1px solid var(--line);background:var(--surface);border-radius:12px;padding:14px 16px}.stat-value{letter-spacing:-.03em;font-size:25px;font-weight:690;line-height:1.1}.stat-label{color:var(--faint);margin-top:3px;font-size:12px}.activity{border:1px solid var(--line);background:var(--surface);color:inherit;border-radius:13px;align-items:flex-start;gap:14px;padding:15px 17px;text-decoration:none;transition:border-color .14s,transform .1s;display:flex}.activity:hover{border-color:var(--line-strong);transform:translateY(-1px)}.activity+.activity{margin-top:10px}.activity-kind{background:var(--raised);border:1px solid var(--line);border-radius:10px;flex:none;place-items:center;width:34px;height:34px;font-size:15px;display:grid}.activity-title{letter-spacing:-.01em;font-size:15.5px;font-weight:620}.activity-detail{color:var(--dim);margin-top:2px;font-size:13.5px}.activity-minutes{color:var(--faint);font-variant-numeric:tabular-nums;flex:none;padding-top:3px;font-size:12px}.unit{border:1px solid var(--line);background:var(--surface);border-radius:14px;margin-bottom:14px;overflow:hidden}.unit-head{border-bottom:1px solid var(--line);background:var(--raised);padding:15px 18px}.unit-name{letter-spacing:-.012em;align-items:center;gap:9px;font-size:16px;font-weight:660;display:flex}.unit-desc{color:var(--dim);max-width:72ch;margin-top:4px;font-size:13.5px}.lesson-row{border-bottom:1px solid var(--line);color:inherit;align-items:center;gap:13px;padding:11px 18px;text-decoration:none;display:flex}.lesson-row:last-child{border-bottom:none}.lesson-row:hover{background:var(--raised)}.lesson-row.locked{opacity:.5}.status-dot{background:var(--line-strong);border-radius:50%;flex:none;width:9px;height:9px}.status-dot.available{background:var(--link)}.status-dot.reading,.status-dot.practising{background:var(--warn)}.status-dot.read,.status-dot.practised{background:var(--accent)}.status-dot.mastered{background:var(--good)}.lesson-row-title{flex:1;font-size:14.8px;font-weight:520}.lesson-row-meta{color:var(--faint);font-variant-numeric:tabular-nums;white-space:nowrap;font-size:12px}.lesson-layout{grid-template-columns:minmax(0,1fr) 218px;align-items:start;gap:42px;display:grid}@media (max-width:1000px){.lesson-layout{grid-template-columns:minmax(0,1fr)}.lesson-aside{display:none}}.lesson-aside{font-size:13px;position:sticky;top:74px}.lesson-aside h3{letter-spacing:.08em;text-transform:uppercase;color:var(--faint);margin:0 0 8px;font-size:11.5px;font-weight:660}.lesson-aside ul{margin:0 0 22px;padding:0;list-style:none}.lesson-aside li{color:var(--dim);margin-bottom:5px;line-height:1.45}.lesson-aside a{color:var(--dim);padding:2px 0;text-decoration:none;display:block}.lesson-aside a:hover{color:var(--ink)}.progress-track{background:var(--line);border-radius:999px;height:3px;margin-bottom:14px;overflow:hidden}.progress-fill{background:linear-gradient(90deg, var(--accent), var(--link));height:100%;transition:width .25s}.lesson-nav{border-top:1px solid var(--line);flex-wrap:wrap;justify-content:space-between;gap:12px;margin-top:46px;padding-top:22px;display:flex}.objectives{border:1px solid var(--line);background:var(--surface);max-width:var(--measure);border-radius:12px;margin:22px 0 30px;padding:14px 17px}.objectives h3{letter-spacing:.08em;text-transform:uppercase;color:var(--faint);margin:0 0 8px;font-size:11.5px;font-weight:660}.objectives ul{color:var(--dim);margin:0;padding-left:20px;font-size:14.5px}.sources{border-top:1px solid var(--line);max-width:var(--measure);margin-top:40px;padding-top:18px}.sources h3{letter-spacing:.08em;text-transform:uppercase;color:var(--faint);margin:0 0 8px;font-size:11.5px;font-weight:660}.sources li{margin-bottom:4px;font-size:13.5px}.review-stage{flex-direction:column;gap:18px;max-width:620px;min-height:340px;margin:0 auto;display:flex}.review-card{border:1px solid var(--line-strong);background:var(--surface);border-radius:16px;flex-direction:column;justify-content:center;min-height:190px;padding:30px 26px;font-size:18px;line-height:1.55;display:flex}.review-card .prose{max-width:none}.review-answer{border-top:1px solid var(--line);color:var(--dim);margin-top:20px;padding-top:18px;font-size:16px}.rating-row{grid-template-columns:repeat(4,1fr);gap:8px;display:grid}.rating-button{border:1px solid var(--line);background:var(--raised);color:var(--ink);font:inherit;cursor:pointer;border-radius:11px;flex-direction:column;align-items:center;gap:2px;padding:11px 8px;transition:border-color .14s,background .14s;display:flex}.rating-button:hover{border-color:var(--faint)}.rating-button b{font-size:14px;font-weight:620}.rating-button small{color:var(--faint);font-variant-numeric:tabular-nums;font-size:11px}.rating-again b{color:var(--bad)}.rating-hard b{color:var(--warn)}.rating-good b{color:var(--link)}.rating-easy b{color:var(--good)}.kbd{border:1px solid var(--line-strong);min-width:17px;font-family:var(--font-mono);color:var(--faint);text-align:center;border-bottom-width:2px;border-radius:4px;padding:0 4px;font-size:10.5px;display:inline-block}.empty-state{text-align:center;color:var(--dim);padding:60px 20px}.empty-state .big{opacity:.5;margin-bottom:10px;font-size:40px}.track-chip{width:21px;height:21px;color:var(--bg);border-radius:6px;place-items:center;font-size:11px;font-weight:700;display:inline-grid}.track-S{background:var(--accent)}.track-U{background:var(--link)}.track-C{background:var(--color-violet)}.track-D{background:var(--good)}.track-P{background:var(--warn)}.track-A{background:var(--color-teal)}