:root{--bg: #f5f5f7;--ink: #1d1d1f;--secondary: #3a3a3c;--tertiary: #6e6e73;--line: rgba(0, 0, 0, .08);--focus: #0071e3;--ease-out: cubic-bezier(.23, 1, .32, 1);--shadow: 0 1px 2px rgba(0, 0, 0, .04), 0 16px 40px rgba(0, 0, 0, .06);color-scheme:light;font:100%/1.5 system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}*,*:before,*:after{box-sizing:border-box}html{-webkit-tap-highlight-color:transparent;-webkit-text-size-adjust:100%;overscroll-behavior:none}body{margin:0;min-height:100svh;background:var(--bg);color:var(--ink);font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;overscroll-behavior:none}button,input{font:inherit;color:inherit}button{background:none;border:0;padding:0;cursor:pointer;touch-action:manipulation;user-select:none;-webkit-user-select:none;-webkit-touch-callout:none}button:disabled{cursor:default}button svg{display:block}::selection{background:#0071e32e}:focus{outline:none}:focus-visible{outline:2px solid var(--focus);outline-offset:3px}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip{position:absolute;left:12px;top:12px;transform:translateY(-200%);background:#fff;color:var(--ink);padding:8px 12px;border-radius:10px;z-index:5;text-decoration:none}.skip:focus{transform:none}.press{transition:transform .1s var(--ease-out),background-color .16s ease,border-color .16s ease,color .16s ease}.press:active:not(:disabled){transform:scale(.97)}.page{min-height:100svh;display:flex;flex-direction:column;background:var(--bg);color:var(--ink)}.topbar{display:flex;justify-content:space-between;align-items:center;gap:12px 20px;flex-wrap:wrap;padding:calc(22px + env(safe-area-inset-top,0px)) calc(28px + env(safe-area-inset-right,0px)) 0 calc(28px + env(safe-area-inset-left,0px))}.wordmark{font-size:15px;font-weight:600;letter-spacing:-.02em}.engine{font-size:12px;font-weight:500;letter-spacing:.08em;text-transform:uppercase;color:var(--tertiary)}.stage{flex:1;display:flex;align-items:center;justify-content:center;padding:32px calc(24px + env(safe-area-inset-right,0px)) 16px calc(24px + env(safe-area-inset-left,0px))}.cluster{width:min(42rem,100%)}.display{margin:0;font-size:clamp(3rem,5vw,4.5rem);font-weight:600;line-height:1.02;letter-spacing:-.035em;font-optical-sizing:auto;text-wrap:balance}.lede{margin:14px 0 0;max-width:38rem;font-size:1.25rem;font-weight:400;line-height:1.45;letter-spacing:0;color:var(--secondary);text-wrap:balance}.enter{animation:enter .28s var(--ease-out) both}.d1{animation-delay:60ms}.d2{animation-delay:.12s}@keyframes enter{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}.ask{margin-top:32px}.field{position:relative;background:#fff;border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);transition:border-color .16s ease,box-shadow .16s ease}.field:focus-within{border-color:var(--focus);box-shadow:0 0 0 4px #0071e32e,var(--shadow)}.field input{width:100%;height:64px;border:0;border-radius:18px;background:transparent;padding:0 68px 0 22px;font-size:17px}.field input::placeholder{color:var(--tertiary)}.field input:focus-visible{outline:none}.go{position:absolute;top:10px;right:10px;width:44px;height:44px;border-radius:50%;background:var(--ink);color:#fff;display:grid;place-items:center}.go svg{width:20px;height:20px}.go:disabled{background:#e8e8ed;color:#8e8e93}.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}.chip{min-height:40px;padding:8px 14px;border-radius:999px;border:1px solid var(--line);background:#fff;color:var(--ink);font-size:14px;font-weight:500;white-space:nowrap;box-shadow:0 1px 2px #00000008}.chip[aria-pressed=true]{background:var(--ink);border-color:var(--ink);color:#fff}.foot{margin:0;text-align:center;color:var(--tertiary);font-size:12px;letter-spacing:.01em;padding:8px 24px calc(20px + env(safe-area-inset-bottom,0px))}.center-copy{flex-direction:column;text-align:center}.spinner{width:28px;height:28px;margin-bottom:22px;border-radius:50%;border:2px solid rgba(0,0,0,.1);border-top-color:var(--ink);animation:spin .6s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.status{margin:0;font-size:1.25rem;font-weight:600;letter-spacing:-.02em;line-height:1.25}.status-line{display:inline-block;animation:fade .2s var(--ease-out)}@keyframes fade{0%{opacity:0}to{opacity:1}}.substatus{margin:8px 0 0;max-width:28rem;color:var(--tertiary);font-size:15px;line-height:1.45}.error-mark{width:56px;height:56px;margin-bottom:16px;border-radius:50%;background:#fdecec;color:#d70015;display:grid;place-items:center}.error-mark svg{width:28px;height:28px}.primary{margin-top:24px;height:44px;padding:0 22px;border-radius:999px;background:var(--ink);color:#fff;font-size:15px;font-weight:600}.shell{height:100dvh;display:flex;flex-direction:column;background:var(--bg);color:var(--ink);overflow:hidden}.bar{flex:none;display:flex;align-items:center;gap:10px;min-height:56px;padding:calc(8px + env(safe-area-inset-top,0px)) calc(16px + env(safe-area-inset-right,0px)) 8px calc(12px + env(safe-area-inset-left,0px));background:#ffffffb8;-webkit-backdrop-filter:blur(20px) saturate(180%);backdrop-filter:blur(20px) saturate(180%);border-bottom:1px solid var(--line)}.back{width:40px;height:40px;border-radius:50%;color:var(--secondary);display:grid;place-items:center;flex:none}.back svg{width:22px;height:22px}.mark{width:32px;height:32px;border-radius:9px;background:var(--ink);color:#fff;display:grid;place-items:center;font-size:14px;font-weight:600;flex:none}.bar-copy{min-width:0;flex:1}.bar-title{margin:0;font-size:15px;font-weight:600;letter-spacing:-.011em;line-height:1.25;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.bar-meta{margin:1px 0 0;font-size:12px;line-height:1.3;color:var(--tertiary);font-variant-numeric:tabular-nums}.workspace{flex:1;min-height:0;display:grid;grid-template-columns:300px minmax(0,1fr) 360px}.workspace>*{min-width:0;min-height:0}.curriculum{overflow:auto;overscroll-behavior:contain;background:#e8e8ed;border-right:1px solid var(--line);padding:22px 14px 28px}.curriculum h2{margin:0 8px 12px;font-size:11px;font-weight:600;letter-spacing:.08em;text-transform:uppercase;color:var(--tertiary)}.module-list{display:flex;flex-direction:column;gap:4px}.module{display:flex;flex-direction:column;align-items:flex-start;gap:6px;width:100%;text-align:left;padding:12px;border-radius:12px;border:1px solid transparent;color:var(--secondary)}.module[aria-current=true]{background:#fff;border-color:var(--line);color:var(--ink);box-shadow:0 1px 2px #0000000a}.module-meta{display:flex;width:100%;justify-content:space-between;align-items:center;gap:8px}.part{flex:none;font-size:11px;font-weight:600;letter-spacing:.02em;padding:2px 7px;border-radius:999px;background:#0000000f;color:var(--secondary)}.module[aria-current=true] .part{background:var(--ink);color:#fff}.duration{flex:none;font-size:12px;color:var(--tertiary);font-variant-numeric:tabular-nums}.module-title{display:block;width:100%;min-width:0;font-size:15px;font-weight:600;letter-spacing:-.011em;line-height:1.3}.study{overflow:auto;overscroll-behavior:contain;padding:36px 40px 48px}.study-inner{max-width:40rem}.overview{margin:0 0 28px;font-size:15px;line-height:1.5;color:var(--tertiary)}.kicker-row{display:flex;align-items:center;gap:10px}.kicker{display:inline-block;padding:4px 10px;border-radius:999px;background:#e8f2fc;color:var(--focus);font-size:12px;font-weight:600;letter-spacing:.02em}.study h2{margin:10px 0 0;font-size:clamp(1.75rem,3vw,2.5rem);font-weight:600;letter-spacing:-.025em;line-height:1.1;text-wrap:balance}.module-copy{margin:14px 0 0;font-size:17px;line-height:1.5;color:var(--secondary)}.card{margin-top:28px;background:#fff;border:1px solid rgba(0,0,0,.06);border-radius:18px;padding:22px 22px 10px;box-shadow:0 1px 2px #0000000a,0 12px 32px #0000000a}.card h3{display:flex;align-items:center;gap:8px;margin:0 0 6px;font-size:15px;font-weight:600}.card h3 svg{width:18px;height:18px;flex:none}.card ul{list-style:none;margin:0;padding:0}.card li{display:flex;gap:10px;align-items:flex-start;padding:9px 0;color:var(--secondary);font-size:15px;line-height:1.45}.card li svg{width:18px;height:18px;flex:none;margin-top:2px;color:#248a3d}.card li span{min-width:0}.tutor{display:flex;flex-direction:column;background:#fff;border-left:1px solid var(--line)}.tutor-bar{flex:none;display:flex;align-items:center;justify-content:space-between;padding:14px 16px;border-bottom:1px solid var(--line)}.tutor-bar>svg{width:16px;height:16px;color:#8e8e93}.presence{display:inline-flex;align-items:center;gap:8px;font-size:12px;font-weight:600;letter-spacing:.02em;color:var(--secondary)}.led{width:8px;height:8px;border-radius:50%;background:#248a3d;flex:none}.log{flex:1;min-height:0;overflow:auto;overscroll-behavior:contain;padding:16px;display:flex;flex-direction:column;gap:12px}.empty-tutor{margin:auto;text-align:center;padding:24px 16px;color:var(--secondary)}.empty-icon{width:48px;height:48px;margin:0 auto 12px;border-radius:14px;background:var(--bg);color:var(--tertiary);display:grid;place-items:center}.empty-icon svg{width:22px;height:22px}.empty-tutor p{margin:0;font-size:15px;line-height:1.45}.empty-tutor strong{color:var(--ink);font-weight:600}.msg{max-width:85%;padding:10px 14px;font-size:15px;line-height:1.5;white-space:pre-wrap;overflow-wrap:anywhere}.msg.user{margin-left:auto;background:var(--ink);color:#fff;border-radius:18px 18px 4px}.msg.model{background:var(--bg);color:var(--ink);border-radius:18px 18px 18px 4px}.typing{display:flex;gap:4px;width:fit-content;padding:12px 14px;background:var(--bg);border-radius:16px 16px 16px 4px}.typing i{width:6px;height:6px;border-radius:50%;background:#8e8e93;animation:bounce 1s ease-in-out infinite}.typing i:nth-child(2){animation-delay:.15s}.typing i:nth-child(3){animation-delay:.3s}@keyframes bounce{0%,80%,to{transform:translateY(0)}40%{transform:translateY(-3px)}}.composer{flex:none;position:relative;padding:12px;padding-bottom:calc(12px + env(safe-area-inset-bottom,0px));border-top:1px solid var(--line)}.composer input{width:100%;height:52px;border-radius:14px;border:1px solid var(--line);background:var(--bg);padding:0 56px 0 16px;font-size:16px;transition:border-color .16s ease,box-shadow .16s ease,background-color .16s ease}.composer input::placeholder{color:var(--tertiary)}.composer input:focus{outline:none;background:#fff;border-color:var(--focus);box-shadow:0 0 0 4px #0071e32e}.composer input:focus-visible{outline:none}.send{position:absolute;top:18px;right:18px;width:40px;height:40px;border-radius:12px;background:var(--ink);color:#fff;display:grid;place-items:center}.send svg{width:18px;height:18px}.send:disabled{background:transparent;color:#8e8e93}@media(max-width:960px){.workspace{display:block;overflow:auto;overscroll-behavior:contain}.curriculum{position:sticky;top:0;z-index:2;display:flex;flex-direction:column;padding:10px 0 0;background:#fff;border-right:0;border-bottom:1px solid var(--line);overflow:hidden}.curriculum h2{margin:0 calc(16px + env(safe-area-inset-right,0px)) 0 calc(16px + env(safe-area-inset-left,0px))}.module-list{flex-direction:row;gap:8px;overflow-x:auto;overscroll-behavior:contain;scroll-snap-type:x mandatory;scroll-padding-inline:16px;padding:8px calc(16px + env(safe-area-inset-right,0px)) 12px calc(16px + env(safe-area-inset-left,0px))}.module{flex:0 0 auto;width:240px;scroll-snap-align:start;background:var(--bg)}.module-title{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.study{overflow:visible;padding:20px 20px 28px}.tutor{height:min(560px,72dvh);min-height:420px;border-left:0;border-top:1px solid var(--line)}}@media(max-width:560px){.engine{letter-spacing:.06em;font-size:11px}.module{width:calc(100vw - 48px)}}@media(hover:hover)and (pointer:fine){.chip:hover{border-color:#0003}.go:hover:not(:disabled),.primary:hover,.send:hover:not(:disabled){background:#2c2c2e}.back:hover,.module:hover{background:#ffffffb8}.module[aria-current=true]:hover{background:#fff}}@media(prefers-reduced-motion:reduce){.enter,.status-line,.spinner,.typing i{animation:none}.press{transition:background-color .16s ease,border-color .16s ease,color .16s 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