@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(../media/inter-cyrillic-ext-wght-normal.1zrieox9119mb.woff2)format("woff2-variations");unicode-range:U+460-52F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(../media/inter-cyrillic-wght-normal.2whpih27xg_2r.woff2)format("woff2-variations");unicode-range:U+301,U+400-45F,U+490-491,U+4B0-4B1,U+2116}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(../media/inter-greek-ext-wght-normal.1xlj4-0oa5zql.woff2)format("woff2-variations");unicode-range:U+1F??}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(../media/inter-greek-wght-normal.1fxkn-ggzj93z.woff2)format("woff2-variations");unicode-range:U+370-377,U+37A-37F,U+384-38A,U+38C,U+38E-3A1,U+3A3-3FF}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(../media/inter-vietnamese-wght-normal.1ahvy37o8m5gt.woff2)format("woff2-variations");unicode-range:U+102-103,U+110-111,U+128-129,U+168-169,U+1A0-1A1,U+1AF-1B0,U+300-301,U+303-304,U+308-309,U+323,U+329,U+1EA0-1EF9,U+20AB}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(../media/inter-latin-ext-wght-normal.2ktx6yqc-sbf1.woff2)format("woff2-variations");unicode-range:U+100-2BA,U+2BD-2C5,U+2C7-2CC,U+2CE-2D7,U+2DD-2FF,U+304,U+308,U+329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}@font-face{font-family:Inter Variable;font-style:normal;font-display:swap;font-weight:100 900;src:url(../media/inter-latin-wght-normal.0rpdhg_4ubdtf.woff2)format("woff2-variations");unicode-range:U+??,U+131,U+152-153,U+2BB-2BC,U+2C6,U+2DA,U+2DC,U+304,U+308,U+329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:Patrick Hand;font-style:normal;font-display:swap;font-weight:400;src:url(../media/patrick-hand-latin-400-normal.221hkg14stmlx.woff2)format("woff2"),url(../media/patrick-hand-latin-400-normal.2pcu6yov5o8l0.woff)format("woff")}
:root{--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark;--shell:#191b21;--chrome:#1d2027;--panel:#20232c;--stroke:#2e333f;--text:#edf0f8;--muted:#a0a8b9;--quiet:#7f899d;--accent:#0096c7;--accent-ink:#080e13;--control-surface:#101113;--control-hover:#24262a;--control-border:#ffffff1c;background:var(--shell);color:var(--text);font-family:Inter Variable,Inter,system-ui,sans-serif}*{box-sizing:border-box}html,body{width:100%;min-height:100%;margin:0}button,textarea,input{font:inherit}button{color:inherit}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible{outline:2px solid var(--accent);outline-offset:3px}button:disabled{opacity:.38;cursor:default}button:not(:disabled){cursor:pointer}svg{vertical-align:middle;flex-shrink:0}::selection{color:#fff;background:#485d9c}.board-app{flex-direction:column;height:100dvh;min-height:350px;display:flex;overflow:hidden}.app-header{z-index:4;flex:0 0 64px;justify-content:space-between;align-items:center;gap:12px;padding:0 24px;display:flex}.brand,.header-actions{align-items:center;display:flex}.brand{letter-spacing:-.022em;min-width:0;color:inherit;gap:11px;font-size:14px;font-weight:625;text-decoration:none}.brand>span{white-space:nowrap;text-overflow:ellipsis;overflow:hidden}.brand-mark{flex-shrink:0;width:32px;height:32px}.board-avatar{color:#fff;object-fit:cover;background:linear-gradient(#416f9e,#1d3b65);border:1px solid #55769e;border-radius:8px;flex-shrink:0;place-items:center;width:32px;height:32px;display:grid}.header-actions{gap:8px}.header-button,.tutor-button,.icon-button,.connect-button,.menu-action,.zoom-count,.check-button{border-radius:999px;transition:background-color .15s,color .15s,border-color .15s}.header-button,.tutor-button{border:1px solid var(--control-border);background:var(--control-surface);white-space:nowrap;justify-content:center;align-items:center;gap:8px;height:36px;padding:0 13px;font-size:12px;font-weight:560;display:flex}.header-button svg{color:#d1d3d9;stroke-width:1.7px}.header-button.board-title{max-width:clamp(106px,25vw,220px)}.header-button.board-nav{width:auto;color:inherit;padding-inline:10px;text-decoration:none}.read-board-title{text-overflow:ellipsis;white-space:nowrap;max-width:190px;font-size:12px;overflow:hidden}.board-title>span{text-overflow:ellipsis;min-width:0;overflow:hidden}.header-button:hover:not(:disabled),.tutor-button:hover,.tutor-button[aria-expanded=true]{background:var(--control-hover)}.tutor-button[aria-expanded=true]{border-color:var(--accent)}.tutor-control{position:relative}.board-workspace{background:#050505;border:1px solid #323641;border-radius:12px;flex-direction:column;flex:auto;min-height:0;margin:0 16px 15px;display:flex;overflow:hidden;box-shadow:0 12px 36px #090a0e33}.stage{isolation:isolate;background:#050505;flex:auto;min-height:0;position:relative;overflow:hidden}.stage.white-board{background:#faf9f4}.board-svg{touch-action:none;-webkit-user-select:none;user-select:none;width:100%;height:100%;display:block;position:absolute;inset:0}.board-svg.tool-pen,.board-svg.tool-graph,.board-svg.tool-eraser{cursor:crosshair}.board-svg.tool-text{cursor:text}.board-svg.tool-hand{cursor:grab}.board-svg.grabbing{cursor:grabbing}.handwriting{font-family:Patrick Hand,Comic Sans MS,cursive}.study-ink-author{font:600 var(--study-label-size,10px) "Inter Variable", Inter, system-ui, sans-serif}.chalk-title{paint-order:stroke;stroke:currentColor;stroke-width:0;letter-spacing:1.2px}.student-text{cursor:inherit}.mark-mistake{animation:.32s ease-out both stroke-in}.graph-writing :is(.chalk-stroke,.graph-axes path){animation:stroke-in .25s calc(var(--diagram-delay,0s) + var(--path-delay,0s)) ease-out both}.graph-writing .chalk-fade{animation:chalk-in .16s calc(var(--diagram-delay,0s) + var(--path-delay,0s)) ease-out both}.write-reveal{transform-box:fill-box;transform-origin:var(--write-origin,left) center;animation:write-in var(--write-for) var(--write-after) ease-out both}.diagram-reveal{animation:diagram-in .18s var(--diagram-delay) both}@keyframes stroke-in{0%{stroke-dasharray:1;stroke-dashoffset:1px}to{stroke-dasharray:1;stroke-dashoffset:0}}@keyframes write-in{0%{transform:scaleX(0)}to{transform:scaleX(1)}}@keyframes diagram-in{0%{opacity:0}to{opacity:1}}@keyframes chalk-in{0%{opacity:0}to{opacity:1}}.start-writing{color:#a2a5ac;opacity:.48;pointer-events:none;font-family:Patrick Hand,Comic Sans MS,cursive;font-size:clamp(17px, calc(25px * var(--guide-scale)), 28px);letter-spacing:.018em;flex-direction:column;gap:12px;display:flex;position:absolute}.guide-line{height:1px;width:min(33vw, calc(303px * var(--guide-scale)));opacity:.56;background:repeating-linear-gradient(90deg,#777d8c 0 4px,#0000 4px 10px);min-width:85px;display:block}.white-board .start-writing{color:#4e5968}.icon-button{color:#c3c6cc;background:0 0;border:1px solid #0000;place-items:center;width:35px;height:35px;padding:0;display:inline-grid}.icon-button svg{stroke-width:1.7px;width:17px;height:17px}.icon-button:hover:not(:disabled){color:var(--text);background:var(--control-hover)}.icon-button.is-active,.icon-button[aria-expanded=true]{color:var(--accent);border-color:var(--control-border);background:var(--control-hover)}.icon-button.is-active:hover:not(:disabled),.icon-button[aria-expanded=true]:hover:not(:disabled){color:var(--accent)}.tools-wrap{z-index:3;position:absolute;top:17px;left:15px}.drawing-tools{border:1px solid var(--control-border);background:var(--control-surface);border-radius:999px;flex-direction:column;align-items:center;gap:3px;width:48px;padding:5px;display:flex;box-shadow:0 6px 18px #0005}.drawing-tools .icon-button{width:36px;height:36px}.tool-divider{background:var(--control-border);width:21px;height:1px;margin:2px 0}.swatch-current{background:var(--swatch);width:15px;height:15px;box-shadow:0 0 0 2px var(--control-surface), 0 0 0 3px #ffffff4d;border-radius:50%}.tool-popover,.tutor-menu{z-index:6;border:1px solid var(--control-border);background:#18191c;border-radius:18px;padding:11px;font-size:12px;position:absolute;box-shadow:0 12px 32px #0007}.tool-popover{width:176px;top:0;left:calc(100% + 9px)}.popover-label{color:#e0e6f3;margin:1px 3px 8px;font-weight:620}.swatch-row{gap:6px;margin:9px 2px 15px;display:flex}.swatch{background:var(--swatch);color:#11131c;border:1px solid #aeb5c342;border-radius:50%;place-items:center;width:23px;height:23px;padding:0;display:grid}.swatch[aria-pressed=true]{box-shadow:0 0 0 2px var(--control-surface), 0 0 0 3px #ced6ed}.slider-label{color:#c0c8da;flex-wrap:wrap;justify-content:space-between;gap:7px;display:flex}.slider-label input{width:100%;accent-color:var(--accent);margin:0}.tutor-menu{width:284px;max-width:calc(100vw - 24px);top:calc(100% + 9px);right:0}.popover-heading{justify-content:space-between;align-items:center;gap:8px;padding-left:4px;display:flex}.popover-heading strong{font-size:14px;font-weight:640}.popover-heading .icon-button{width:27px;height:27px}.popover-heading .icon-button svg{width:15px;height:15px}.tutor-connect{padding:4px 4px 10px}.tutor-connect p,.board-dialog p{color:#b5bfd4;margin:4px 0 11px;font-size:12px;line-height:1.55}.connect-button,.check-button{color:var(--accent-ink);background:var(--accent);border:0;font-weight:660;transition:filter .15s}.connect-button:hover:not(:disabled),.check-button:hover:not(:disabled){filter:brightness(1.12)}.connect-button{width:100%;min-height:36px;padding:8px 14px;font-size:12px;display:block}.menu-action,.toggle-row{width:100%;min-height:34px;color:var(--text);text-align:left;background:0 0;border:0;align-items:center;gap:9px;padding:6px 10px;font-size:12px;display:flex}.menu-action:hover:not(:disabled){background:var(--control-hover)}.menu-action>svg{color:#b7bbc2;stroke-width:1.7px;width:15px;height:15px}.tutor-actions{border-top:1px solid var(--control-border);padding-top:5px}.toggle-row{justify-content:space-between}.tutor-language select{border:1px solid var(--control-border);background:var(--control-surface);min-height:28px;color:inherit;font:inherit;border-radius:8px;padding:3px 7px}.tutor-language select:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.toggle-row input{appearance:none;border:1px solid var(--control-border);cursor:pointer;background:#3a3c42;border-radius:999px;flex-shrink:0;width:32px;height:19px;margin:0;padding:2px;transition:background-color .15s}.toggle-row input:after{content:"";background:var(--text);border-radius:50%;width:13px;height:13px;transition:transform .15s;display:block}.toggle-row input:checked{background:var(--accent)}.toggle-row input:checked:after{background:var(--accent-ink);transform:translate(13px)}.demo-action{justify-content:space-between;margin-top:5px}.disconnect{color:#a7b0c4}.tutor-connect .connected-label{color:var(--text);align-items:center;gap:6px;display:flex}.connected-label>span{background:var(--accent);border-radius:50%;width:6px;height:6px}.manage-usage{color:var(--accent);font-size:12px;text-decoration:none}.manage-usage:hover{text-decoration:underline}.board-footer{z-index:2;color:#aab2c6;background:#1b1e26;border-top:1px solid #2e333d;flex:0 0 45px;grid-template-columns:1fr auto 1fr;align-items:center;gap:9px;padding:0 9px;display:grid}.page-controls,.check-controls,.view-controls{align-items:center;gap:2px;min-width:0;display:flex}.view-controls{justify-content:flex-end}.check-controls{justify-content:center;gap:13px}.board-footer .icon-button{width:30px;height:31px}.board-footer .icon-button svg{width:15px;height:15px}.page-count{text-align:center;font-variant-numeric:tabular-nums;white-space:nowrap;color:#c4cbdc;min-width:30px;font-size:11px;font-weight:600}.page-count span{color:#7f89a0;font-weight:430}.page-add{margin-left:3px}.footer-divider{background:var(--stroke);width:1px;height:17px;margin:0 4px}.zoom-count{color:#c6cde0;font-variant-numeric:tabular-nums;background:0 0;border:0;min-width:56px;height:30px;font-size:11px;font-weight:560}.zoom-count:hover{background:var(--control-hover)}.check-status{color:#a4aec2;white-space:nowrap;align-items:center;gap:7px;font-size:11px;font-weight:510;display:flex}.check-status>i{background:var(--quiet);border-radius:50%;width:6px;height:6px}.check-status.status-checking,.check-status.status-solving,.check-status.status-waiting{color:var(--accent)}.check-status.status-flagged>i{background:#ff736a}.check-status.status-correct{color:#abd8b8}.check-button{place-items:center;width:34px;height:34px;padding:0;display:inline-grid}.inline-editor{z-index:2;appearance:none;resize:none;caret-color:currentColor;scrollbar-width:none;background:0 0;border:0;width:clamp(185px,39vw,540px);max-width:min(540px,100% - 44px);max-height:55%;padding:0;font-family:Patrick Hand,Comic Sans MS,cursive;line-height:1.2;display:block;position:absolute}.inline-editor:focus-visible{outline:none}@supports (field-sizing:content){.inline-editor{field-sizing:content;width:auto;min-width:1ch;min-height:1lh}}.stage-notice,.floating-tip,.toast{pointer-events:none;z-index:3;color:#e2e9fb;background:#212734;border:1px solid #3c465b;border-radius:9px;padding:10px 13px;font-size:12px;position:absolute;box-shadow:0 4px 18px #0004}.stage-notice{white-space:nowrap;align-items:center;gap:9px;display:flex;top:50%;left:50%;transform:translate(-50%,-50%)}.drop-target{border-style:dashed;border-color:#9eb4ff;padding:22px 25px;font-weight:600}.floating-tip{white-space:nowrap;top:13px;left:50%;transform:translate(-50%)}.toast{max-width:calc(100% - 30px);line-height:1.45;bottom:15px;left:15px}.spinning{animation:1s linear infinite spin}@keyframes spin{to{transform:rotate(360deg)}}.board-dialog{border:1px solid var(--control-border);color:#e7edf9;background:#18191c;border-radius:20px;width:min(407px,100vw - 28px);padding:0;box-shadow:0 12px 45px #0008}.board-dialog::backdrop{background:#080b13a8}.board-dialog form,.dialog-content{padding:16px}.board-dialog .popover-heading{margin-bottom:12px;padding-left:0}.board-dialog label,.tutor-access-form label{color:#c9d3e6;flex-direction:column;gap:6px;margin-bottom:11px;font-size:12px;display:flex}.board-dialog input,.board-dialog textarea,.tutor-access-form input{color:#eef3ff;background:#181d29;border:1px solid #3f485e;border-radius:6px;width:100%;padding:8px}.board-dialog textarea{resize:vertical}.board-tools-dialog{width:min(520px,100vw - 28px)}.board-tool-actions{flex-wrap:wrap;gap:8px;display:flex}.board-tool-actions .header-button{width:auto;padding-inline:13px}.board-tool-status{color:#b8c7e2;margin:10px 0 0;font-size:12px;line-height:1.5}.board-tool-status:empty{display:none}.board-summary{border-top:1px solid var(--control-border);overflow-wrap:anywhere;margin-top:15px;padding-top:12px;font-size:14px;line-height:1.55}.board-summary h2{margin:0 0 5px;font-size:17px}.board-summary h3{margin:12px 0 4px;font-size:13px}.board-summary p,.board-summary ul{margin:0}.board-summary ul{padding-left:19px}.board-summary li+li{margin-top:4px}.board-dialog .connect-button{margin-top:12px}@media (max-width:760px){.app-header{flex-basis:57px;padding:0 13px}.board-workspace{border-radius:9px;margin:0 8px 8px}.tools-wrap{top:11px;left:10px}.drawing-tools{flex-direction:row;gap:2px;width:max-content}.drawing-tools .icon-button{width:34px;height:34px}.tool-divider{width:1px;height:20px;margin:0 2px}.tool-popover{top:calc(100% + 7px);left:0}.board-svg{margin-top:0}.floating-tip{top:63px}.check-controls{gap:6px}}@media (max-width:510px){.brand{gap:7px;font-size:12px}.brand-mark,.board-avatar{width:28px;height:28px}.app-header{flex-wrap:wrap;flex-basis:auto;gap:6px;padding-block:8px}.app-header .brand{flex-basis:100%}.header-actions{gap:5px}.header-button{width:34px;padding:0}.header-button>span{display:none}.header-button.board-title{width:auto;padding:0 7px}.header-button.board-title>span{display:block}.read-board-title{max-width:110px}.tutor-button{padding-inline:10px}.board-footer{gap:3px;padding:0 5px}.board-footer .icon-button{width:25px}.check-status>span{display:none}.check-status{gap:0}.zoom-count{min-width:39px}.view-controls,.page-controls{gap:0}.footer-divider{margin:0 2px}}@media (max-height:570px) and (min-width:761px){.drawing-tools{gap:1px}.drawing-tools .icon-button{width:30px;height:30px}}@media (prefers-reduced-motion:reduce){.mark-mistake,.graph-writing :is(.chalk-stroke,.graph-axes path,.chalk-fade),.write-reveal,.diagram-reveal,.spinning{animation:none}.header-button,.tutor-button,.icon-button,.connect-button,.menu-action,.zoom-count,.check-button,.toggle-row input,.toggle-row input:after{transition:none}}@media (max-width:365px){.drawing-tools{gap:1px;padding:3px}.drawing-tools .icon-button{width:31px;height:33px}.tool-divider{margin-inline:1px}}@media (pointer:coarse) and (min-width:760px){.drawing-tools{width:54px}.drawing-tools .icon-button{width:42px;height:42px}}.tutor-emphasis{animation:.44s ease-out both stroke-in}.chalk-tip{animation:chalk-tip var(--write-for) linear var(--write-after) both}@keyframes chalk-tip{0%{opacity:0;transform:translate(0)}9%{opacity:1}92%{opacity:1}to{opacity:0;transform:translateX(var(--chalk-travel))}}@media (prefers-reduced-motion:reduce){.tutor-emphasis{animation:none}.chalk-tip{display:none}}