.guest-header{box-sizing:border-box;text-align:left;flex-wrap:wrap;align-items:center;gap:16px;width:100%;max-width:1200px;margin:0 auto;padding:20px 24px;display:flex}.guest-header-logo{min-height:44px;color:var(--text-h);align-items:center;gap:10px;text-decoration:none;display:flex}.guest-header-mark{background:var(--landing-accent,#1f4fd1);color:#fff;width:40px;height:40px;font:700 20px var(--landing-display,var(--heading));border-radius:10px;justify-content:center;align-items:center;display:flex}.guest-header-name{font:700 20px var(--landing-display,var(--heading))}.guest-header-sections{flex-wrap:wrap;gap:20px;margin-left:auto;font-size:15px;display:flex}.guest-header-sections a{color:var(--text-h);text-decoration:none}.guest-header-actions{flex-wrap:wrap;align-items:center;gap:10px;margin-left:auto;display:flex}.guest-header-sections+.guest-header-actions{margin-left:0}.guest-header-login,.guest-header-register,.sign-up-prompt-register{box-sizing:border-box;border-radius:10px;align-items:center;min-height:44px;padding:10px 16px;font-weight:500;text-decoration:none;display:inline-flex}.guest-header-login{border:1px solid var(--border);background:var(--bg);color:var(--text-h)}.guest-header-register,.sign-up-prompt-register{background:var(--text-h);color:var(--bg)}.sign-up-prompt{border:1px solid var(--border);text-align:left;border-radius:12px;margin:16px 0;padding:16px 20px}.sign-up-prompt p{color:var(--text-h);margin:0 0 12px}.sign-up-prompt-actions{flex-wrap:wrap;align-items:center;gap:16px;display:flex}@media (width<=640px){.guest-header{padding:12px 16px}.guest-header-sections{display:none}}:root{--text:#6b6375;--text-h:#08060d;--bg:#fff;--border:#e5e4e7;--code-bg:#f4f3ec;--accent:#aa3bff;--accent-bg:#aa3bff1a;--accent-border:#aa3bff80;--social-bg:#f4f3ec80;--shadow:#0000001a 0 10px 15px -3px, #0000000d 0 4px 6px -2px;--sans:system-ui, "Segoe UI", Roboto, sans-serif;--heading:system-ui, "Segoe UI", Roboto, sans-serif;--mono:ui-monospace, Consolas, monospace;font:18px/145% var(--sans);letter-spacing:.18px;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light dark;color:var(--text);background:var(--bg);font-synthesis:none;text-rendering:optimizelegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}@media (prefers-color-scheme:dark){:root{--lightningcss-light: ;--lightningcss-dark:initial}}@media (width<=1024px){:root{font-size:16px}}@media (prefers-color-scheme:dark){:root{--text:#9ca3af;--text-h:#f3f4f6;--bg:#16171d;--border:#2e303a;--code-bg:#1f2028;--accent:#c084fc;--accent-bg:#c084fc26;--accent-border:#c084fc80;--social-bg:#2f303a80;--shadow:#0006 0 10px 15px -3px, #00000040 0 4px 6px -2px}#social .button-icon{filter:invert()brightness(2)}}#root{text-align:center;border-inline:1px solid var(--border);box-sizing:border-box;flex-direction:column;width:1126px;max-width:100%;min-height:100svh;margin:0 auto;display:flex}body{margin:0}h1,h2{font-family:var(--heading);color:var(--text-h);font-weight:500}h1{letter-spacing:-1.68px;margin:32px 0;font-size:56px}@media (width<=1024px){h1{margin:20px 0;font-size:36px}}h2{letter-spacing:-.24px;margin:0 0 8px;font-size:24px;line-height:118%}@media (width<=1024px){h2{font-size:20px}}p{margin:0}code,.counter{font-family:var(--mono);color:var(--text-h);border-radius:4px;display:inline-flex}code{background:var(--code-bg);padding:4px 8px;font-size:15px;line-height:135%}.navbar{border-bottom:1px solid var(--border);text-align:left;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:16px;padding:12px 24px;display:flex;position:relative}.navbar-links{flex-wrap:wrap;align-items:center;gap:4px;display:flex}.navbar-link{color:var(--text);border-radius:6px;padding:6px 12px;font-size:15px;text-decoration:none;display:inline-block}.navbar-link:hover{background:var(--accent-bg)}.navbar-link-active{background:var(--accent-bg);color:var(--text-h);font-weight:600}.navbar-user{align-items:center;gap:12px;font-size:15px;display:flex}.navbar-role{color:var(--text)}.navbar-user button{border:1px solid var(--border);color:var(--text);cursor:pointer;font:inherit;background:0 0;border-radius:6px;padding:6px 12px}.navbar-user button:hover{border-color:var(--accent-border);color:var(--text-h)}.navbar-more{display:none}@media (width<=1024px){body{padding-bottom:56px}.navbar-role{display:none}.navbar-links{z-index:10;box-sizing:border-box;background:var(--bg);border-top:1px solid var(--border);flex-wrap:nowrap;gap:0;height:56px;padding:4px 0;position:fixed;bottom:0;left:0;right:0}.navbar-link{text-align:center;white-space:nowrap;text-overflow:ellipsis;border-radius:0;flex:1;min-width:0;padding:8px 2px;font-size:12px;line-height:1.2;overflow:hidden}.navbar-link-more,.navbar-help{display:none}.navbar-more{flex:1;min-width:0;display:flex;position:relative}.navbar-more-toggle{width:100%;font:inherit;cursor:pointer;background:0 0;border:0;font-size:12px}.navbar-more-list{background:var(--bg);border:1px solid var(--border);min-width:220px;box-shadow:var(--shadow);border-radius:8px;margin:0;padding:4px 0;list-style:none;position:absolute;bottom:calc(100% + 8px);right:4px}.navbar-more-list a{color:var(--text-h);padding:12px 16px;font-size:15px;text-decoration:none;display:block}.navbar-more-list a:hover,.navbar-more-list a.active{background:var(--accent-bg)}}.slot-picker{flex-direction:column;align-items:flex-start;gap:12px;display:flex}.slot-picker-day{color:var(--text-h);align-items:center;gap:12px;font-weight:600;display:flex}.slot-picker-day button{border:1px solid var(--border);color:var(--text);cursor:pointer;font:inherit;background:0 0;border-radius:6px;padding:4px 10px}.slot-picker-day button:disabled{opacity:.4;cursor:default}.slot-grid,.slot-duration{grid-template-columns:repeat(auto-fill,minmax(64px,1fr));gap:6px;width:100%;display:grid}.slot-button{border:1px solid var(--border);color:var(--text);cursor:pointer;font:inherit;background:0 0;border-radius:6px;padding:6px 8px;font-size:14px}.slot-button:hover:not(:disabled){border-color:var(--accent-border)}.slot-button:disabled{opacity:.4;cursor:default}.slot-button-selected{background:var(--accent-bg);border-color:var(--accent-border);color:var(--text-h);font-weight:600}.sx-react-calendar-wrapper{width:100%;height:600px;max-height:80vh}.sx-react-calendar-wrapper .sx__month-agenda-day__event-icon{filter:none;width:7px;height:7px}.sx-react-calendar-wrapper .sx__month-agenda-day-name{text-transform:uppercase}.calendar-empty{color:var(--text);text-align:center;margin:0 0 12px}.notification-badge{background:var(--accent-border);color:var(--text-h);border-radius:999px;margin-left:4px;padding:0 6px;font-size:12px}.notification-dropdown{z-index:20;border:1px solid var(--border);background:var(--bg,#fff);border-radius:8px;width:min(360px,100vw - 32px);padding:12px;position:absolute;top:calc(100% + 6px);right:0;box-shadow:0 6px 24px #00000026}.notification-dropdown ul{gap:10px;margin:0;padding:0;list-style:none;display:grid}.instant-lesson-banner,.app-update-banner{border-bottom:1px solid var(--accent-border);color:var(--text-h);flex-wrap:wrap;align-items:center;gap:12px;padding:10px 24px;display:flex}.lesson-room-toolbar{flex-wrap:wrap;justify-content:center;gap:8px;padding:8px;display:flex}.lesson-workspace{gap:8px;min-height:0;display:flex}.lesson-board{flex:1 1 0;min-width:0;height:100%;min-height:0}.lesson-sidebar{border:1px solid var(--border);text-align:left;border-radius:8px;flex-direction:column;flex:none;width:280px;max-width:50%;min-height:0;display:flex}.lesson-sidebar[data-tab=formula]{width:340px}.lesson-sidebar[data-tab=graph]{width:520px}.lesson-sidebar[data-open=false]{width:auto}.lesson-sidebar[data-open=false]>button{writing-mode:vertical-rl;flex:1}.lesson-sidebar-tabs{border-bottom:1px solid var(--border);gap:4px;padding:4px;display:flex}.lesson-sidebar-tabs [role=tablist]{flex:1;gap:4px;min-width:0;display:flex}.lesson-sidebar-tabs [role=tab]{white-space:nowrap;flex:1 1 0;min-width:0;padding:4px 6px;font-size:14px}.lesson-sidebar-hide{border:1px solid var(--border);min-width:40px;min-height:40px;color:var(--text);cursor:pointer;background:0 0;border-radius:8px;flex:none;font-size:18px}@media (pointer:coarse){.lesson-sidebar-hide{min-width:44px;min-height:44px}}.lesson-sidebar-tabs [role=tab][aria-selected=true]{border-color:var(--accent);color:var(--accent)}.lesson-sidebar-body{flex-direction:column;flex:1;min-height:0;display:flex;overflow:auto}.lesson-sidebar-body .lesson-tool-panel{border:0;max-width:none;margin:0;padding:8px}.lesson-chat-panel{flex-direction:column;flex:1;gap:6px;min-height:0;padding:8px;display:flex}.lesson-chat-messages{flex:1;min-height:0;margin:0;padding:0;list-style:none;overflow-y:auto}.lesson-chat-panel textarea{resize:none;min-height:3em}@media (width<=640px){.lesson-workspace{flex-direction:column}.lesson-board{height:auto}.lesson-sidebar,.lesson-sidebar[data-tab]{width:auto;max-width:none}.lesson-sidebar[data-open=true]{max-height:50%}.lesson-sidebar[data-open=false]{flex-direction:row}.lesson-sidebar[data-open=false]>button{writing-mode:horizontal-tb}}.floating-window{border:1px solid var(--border);box-shadow:var(--shadow);background:#000;border-radius:8px;flex-direction:column;display:flex;position:fixed;overflow:hidden}.floating-window-titlebar{color:var(--text-h);background:var(--code-bg);cursor:move;-webkit-user-select:none;user-select:none;touch-action:none;justify-content:space-between;gap:8px;padding:2px 8px;font-size:13px;display:flex}.floating-window-body{flex:1;min-height:0}.floating-window-body video{object-fit:cover;width:100%;height:100%;display:block}.floating-window-resize{cursor:nwse-resize;touch-action:none;background:linear-gradient(135deg, transparent 50%, var(--accent-border) 50%);width:18px;height:18px;position:absolute;bottom:0;right:0}.floating-window-title{text-overflow:ellipsis;white-space:nowrap;min-width:0;overflow:hidden}.floating-window-tools{flex-shrink:0;align-items:center;gap:6px;display:flex}.floating-window-fold{min-width:28px;min-height:24px;color:var(--text-h);cursor:pointer;background:0 0;border:0;padding:0 6px;font-size:16px;line-height:1}@media (pointer:coarse){.floating-window-fold{min-width:44px;min-height:32px;font-size:22px}}.window-dot{border:3px solid var(--presence-color);width:44px;height:44px;color:var(--text-h);background:var(--code-bg);box-shadow:var(--shadow);cursor:pointer;touch-action:none;-webkit-user-select:none;user-select:none;border-radius:50%;padding:0;font-size:15px;font-weight:600;position:fixed}.window-dot[data-presence=online]{--presence-color:#22a559}.window-dot[data-presence=offline]{--presence-color:#e0393e}.window-dot[data-presence=waiting]{--presence-color:#9a98a0}.window-dot[data-presence=self]{--presence-color:var(--accent-border)}.window-dot-badge{font-size:14px;position:absolute;bottom:-6px;right:-6px}.mini-lesson{flex-direction:column;height:100%;display:flex}.mini-lesson-videos{flex:1;gap:2px;min-height:0;display:grid;overflow:hidden}.mini-lesson-grid{grid-template-columns:repeat(auto-fit,minmax(100px,1fr));grid-auto-rows:minmax(0,1fr)}.mini-lesson-tile{background:#000;min-height:0;margin:0;position:relative;overflow:hidden}.mini-lesson-tile figcaption,.mini-lesson-no-connection{color:#fff;pointer-events:none;font-size:12px;position:absolute}.mini-lesson-tile figcaption{text-overflow:ellipsis;white-space:nowrap;background:#0009;border-radius:4px;max-width:calc(100% - 8px);padding:1px 6px;bottom:4px;left:4px;overflow:hidden}.mini-lesson-no-connection{white-space:nowrap;top:50%;left:50%;transform:translate(-50%,-50%)}.mini-lesson-status{color:#fff;margin:0;padding:4px 8px;font-size:13px}.mini-lesson-actions{background:var(--code-bg);flex-wrap:wrap;gap:4px;padding:6px;display:flex}.mini-lesson-actions button{flex:auto;font-size:13px}.lesson-tool-panel{border:1px solid var(--border);text-align:left;border-radius:8px;max-width:640px;margin:16px auto;padding:12px 16px;overflow-x:auto}.lesson-tool-panel h3{color:var(--text-h);margin:0 0 4px}.lesson-tool-hint{margin:0 0 12px;font-size:15px}.lesson-tool-hint kbd{font-family:var(--mono);border:1px solid var(--border);background:var(--code-bg);border-radius:4px;padding:0 4px}.graph-modes{flex-wrap:wrap;gap:6px;margin-bottom:8px;display:flex}.graph-modes button[aria-pressed=true]{background:var(--accent-bg);border-color:var(--accent);color:var(--text-h)}.graph-function-form{align-items:center;gap:8px;margin-top:12px;display:flex}.graph-function-form input{min-width:0;font-family:var(--mono);flex:1}.graph-error{color:#dc2626;margin:4px 0 0;font-size:15px}.graph-functions{margin:8px 0 0;padding:0;list-style:none}.graph-functions li{font-family:var(--mono);align-items:center;gap:8px;display:flex}.graph-swatch{border-radius:2px;flex:none;width:12px;height:12px}.graph-clear{margin-top:16px}.navbar-help{color:var(--text);font-size:15px;text-decoration:none}.navbar-help:hover{color:var(--text-h)}.navbar-name{color:inherit;text-decoration:none}.navbar-name:hover{text-decoration:underline}button.danger{font:inherit;background:var(--danger,#c62828);color:#fff;cursor:pointer;border:1px solid #0000;border-radius:8px;min-height:40px;padding:6px 12px}button.danger:disabled{opacity:.5;cursor:default}.lesson-room-toolbar a{align-self:center}.help-page{text-align:left;max-width:760px;margin:0 auto;padding:0 16px 32px}.help-page h2{color:var(--text-h);background:0 0;margin-top:32px}.help-about,.licenses-page{box-sizing:border-box;width:100%}.help-about{padding-bottom:48px}.licenses-text{white-space:pre-wrap;overflow-wrap:anywhere;font-family:var(--mono);font-size:12px;line-height:1.5}.help-question{border-bottom:1px solid var(--border);padding:10px 0}.help-question summary{cursor:pointer;color:var(--text-h);font-weight:500}.help-answer{padding:4px 0 0 18px}.help-answer kbd{font-family:var(--mono);border:1px solid var(--border);background:var(--code-bg);border-radius:4px;padding:0 4px}.help-examples{flex-wrap:wrap;gap:8px;padding:0;list-style:none;display:flex}.request-actions{gap:6px;margin-left:10px;display:inline-flex}.language-switcher{border:1px solid var(--border);border-radius:8px;flex-shrink:0;display:inline-flex;overflow:hidden}.language-switcher button{color:var(--text);background:0 0;border:0;border-radius:0;padding:4px 8px;font-size:13px}.language-switcher button[aria-pressed=true]{background:var(--accent-bg);color:var(--text-h);font-weight:600}.ru-only-notice,.page-notice{border:1px solid var(--border);background:var(--accent-bg);color:var(--text-h);border-radius:8px;margin:0 0 16px;padding:8px 12px}.lesson-list{margin:0 0 16px;padding:0;list-style:none}.lesson-list li{border-bottom:1px solid var(--border);padding:8px 0}.lesson-join,.past-lessons-toggle,.lesson-list-more{border:1px solid var(--accent-border);background:var(--accent-bg);color:var(--text-h);cursor:pointer;font:inherit;border-radius:6px;padding:4px 12px;text-decoration:none;display:inline-block}.past-lessons-toggle,.lesson-list-more{border-color:var(--border);color:var(--text);background:0 0}.lesson-join:hover,.past-lessons-toggle:hover,.lesson-list-more:hover:not(:disabled){border-color:var(--accent)}.past-lessons{margin-top:24px}.join-requests{border:1px solid var(--accent-border);background:var(--accent-bg);color:var(--text-h);border-radius:8px;margin:0 0 8px;padding:8px 12px;list-style:none}.join-requests li+li{margin-top:6px}.cancel-bar{margin:8px 0}.cancel-dialog textarea{width:100%;min-height:60px;font:inherit;margin:6px 0;display:block}.pending-items h2{font-size:1.1rem}.setup-form{text-align:left;flex-direction:column;align-items:stretch;gap:8px;max-width:560px;margin:0 auto;display:flex}.setup-form input,.setup-form textarea,.setup-form select{font:inherit;box-sizing:border-box;min-height:44px;padding:8px 10px}.setup-form button{font:inherit;align-self:flex-start;min-height:44px;padding:0 18px}.setup-subjects{border:0;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:4px 16px;margin:0;padding:0;display:grid}.setup-check{align-items:center;gap:10px;min-height:44px;display:flex}.setup-check input{width:22px;height:22px;min-height:0}.setup-documents,.setup-slot-list{text-align:left;margin:8px 0;padding:0;list-style:none}.setup-documents li,.setup-slot-list li{border-bottom:1px solid var(--border);padding:8px 0}.setup-primary{font:inherit;min-height:44px;padding:0 18px}.setup-panel-body{text-align:left;padding:0 16px}.setup-wizard{max-width:640px;margin:0 auto;padding:0 16px}.setup-progress-label{font-weight:600}.setup-progress{justify-content:center;gap:30px;margin:8px 0 20px;padding:0;list-style:none;display:flex}.setup-dot{background:var(--border);border-radius:50%;width:14px;height:14px;position:relative}.setup-dot-done{background:color-mix(in srgb, var(--accent) 55%, transparent)}.setup-dot-current{background:var(--accent)}.setup-dot button{cursor:pointer;background:0 0;border:0;padding:0;position:absolute;inset:-15px}.setup-step{margin-bottom:16px}.setup-back{font:inherit;min-height:44px;padding:0 18px}.setup-checklist{border:1px solid var(--border);text-align:left;border-radius:12px;max-width:640px;margin:0 auto 16px;padding:12px 16px}.setup-checklist h2{margin:0 0 8px;font-size:1.1rem}.setup-checklist ul{flex-wrap:wrap;gap:4px 16px;margin:0 0 8px;padding:0;list-style:none;display:flex}.setup-check-missing{opacity:.6}.setup-tabs{flex-wrap:wrap;justify-content:center;gap:6px;margin:0 auto 16px;padding:0 16px;display:flex}.setup-tab{font:inherit;border:1px solid var(--border);cursor:pointer;background:0 0;border-radius:22px;min-height:44px;padding:0 16px}.setup-tab-active{background:var(--accent-bg);border-color:var(--accent);font-weight:600}.setup-panel{max-width:720px;margin:0 auto;padding:0 16px}.visually-hidden{clip:rect(0 0 0 0);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}:where(button,input:not([type=checkbox],[type=radio]),select,textarea):where(:not([class],.floating-window *,.mini-lesson *)){font:inherit;color:var(--text-h);background:var(--bg);border:1px solid var(--border);box-sizing:border-box;border-radius:8px;min-height:40px;padding:6px 12px}:where(button):where(:not([class],.floating-window *,.mini-lesson *)){cursor:pointer}:where(button):where(:not([class],.floating-window *,.mini-lesson *)):hover:not(:disabled){border-color:var(--accent-border)}:where(button):where(:not([class],.floating-window *,.mini-lesson *)):disabled{opacity:.5;cursor:default}:where(input[type=checkbox],input[type=radio]):where(:not([class],.floating-window *,.mini-lesson *)){vertical-align:middle;width:20px;height:20px;accent-color:var(--accent);margin:0 6px}@media (pointer:coarse){:where(button,input:not([type=checkbox],[type=radio]),select,textarea):where(:not([class],.floating-window *,.mini-lesson *)){min-height:44px}:where(input[type=checkbox],input[type=radio]):where(:not([class],.floating-window *,.mini-lesson *)){width:22px;height:22px}}.stack-form{box-sizing:border-box;text-align:left;flex-direction:column;align-items:stretch;gap:10px;width:100%;max-width:560px;margin:0 auto 16px;padding:0 16px;display:flex}.stack-form>h1,.stack-form>h2{text-align:center}.stack-form>.language-switcher{align-self:center}.stack-form label{flex-direction:column;gap:4px;display:flex}.stack-form label:has(>input[type=checkbox],>input[type=radio]){min-height:44px;display:block}.stack-form>button{align-self:flex-start;padding:0 20px}.stack-form fieldset{border:1px solid var(--border);border-radius:8px;flex-direction:column;gap:2px;margin:0;padding:8px 12px;display:flex}.stack-form fieldset.register-fields{border:0;margin:0;padding:0;display:contents}.stack-form .password-field{flex-direction:column;gap:4px;display:flex}.account-page{box-sizing:border-box;text-align:left;width:100%;max-width:560px;margin:0 auto 16px;padding:0 16px}.account-page>h1{text-align:center}.account-page dl{grid-template-columns:max-content minmax(0,1fr);gap:6px 16px;display:grid}.account-page dd{color:var(--text-h);overflow-wrap:anywhere;margin:0}.account-page section{flex-direction:column;gap:8px;margin-top:28px;display:flex}.account-page section>h2,.account-page section>p{margin:0}.account-page section>button{align-self:flex-start}.account-page form,.account-page .account-choose{flex-direction:column;align-items:stretch;gap:10px;display:flex}.account-page form>button,.account-page .account-choose>button{align-self:flex-start}.account-page .account-choose label,.account-page .form-field{flex-direction:column;gap:4px;display:flex}.account-page .form-hint{margin:0;font-size:.9em}.account-page .password-input{display:flex}.account-page .stack-form{max-width:none;margin:0;padding:0}.password-input{vertical-align:middle;align-items:center;display:inline-flex;position:relative}.stack-form .password-input{display:flex}.password-input>input{flex:1;min-width:0;padding-right:44px}.password-toggle{width:40px;height:36px;color:var(--text);cursor:pointer;background:0 0;border:0;border-radius:6px;justify-content:center;align-items:center;padding:0;display:inline-flex;position:absolute;top:50%;right:2px;transform:translateY(-50%)}.password-toggle:hover,.password-toggle[aria-pressed=true]{color:var(--text-h)}.password-toggle:focus-visible{outline:2px solid var(--accent);outline-offset:-2px}@media (pointer:coarse){.password-toggle{width:44px;height:40px}}span.teacher-code,.teacher-code strong{font-family:var(--mono)}.filter-row{flex-wrap:wrap;justify-content:center;align-items:center;gap:8px 20px;margin:0 auto 16px;padding:0 16px;display:flex}.filter-row label{align-items:center;gap:8px;display:inline-flex}.lesson-join,.past-lessons-toggle,.lesson-list-more{box-sizing:border-box;vertical-align:middle;align-items:center;min-height:40px;display:inline-flex}@media (pointer:coarse){.lesson-join,.past-lessons-toggle,.lesson-list-more{min-height:44px}}.notification-bell>button{white-space:nowrap;align-items:center;gap:4px;display:inline-flex}