@font-face{font-family:Inter Tight;font-style:normal;font-display:swap;font-weight:700;src:url(/assets/inter-tight-cyrillic-ext-700-normal-D_7NT8eF.woff2)format("woff2"),url(/assets/inter-tight-cyrillic-ext-700-normal-BFcoPt71.woff)format("woff");unicode-range:U+460-52F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:Inter Tight;font-style:normal;font-display:swap;font-weight:700;src:url(/assets/inter-tight-cyrillic-700-normal-DtWWjp29.woff2)format("woff2"),url(/assets/inter-tight-cyrillic-700-normal-DDZiLR3d.woff)format("woff");unicode-range:U+301,U+400-45F,U+490-491,U+4B0-4B1,U+2116}@font-face{font-family:Inter Tight;font-style:normal;font-display:swap;font-weight:700;src:url(/assets/inter-tight-greek-ext-700-normal-D0RkHJEE.woff2)format("woff2"),url(/assets/inter-tight-greek-ext-700-normal-mW3dmpoD.woff)format("woff");unicode-range:U+1F??}@font-face{font-family:Inter Tight;font-style:normal;font-display:swap;font-weight:700;src:url(/assets/inter-tight-greek-700-normal-RgALSHS4.woff2)format("woff2"),url(/assets/inter-tight-greek-700-normal-DU8XoIeX.woff)format("woff");unicode-range:U+370-377,U+37A-37F,U+384-38A,U+38C,U+38E-3A1,U+3A3-3FF}@font-face{font-family:Inter Tight;font-style:normal;font-display:swap;font-weight:700;src:url(/assets/inter-tight-vietnamese-700-normal-Cn_DV52A.woff2)format("woff2"),url(/assets/inter-tight-vietnamese-700-normal-DwHBAXeT.woff)format("woff");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 Tight;font-style:normal;font-display:swap;font-weight:700;src:url(/assets/inter-tight-latin-ext-700-normal-BpKPOkj3.woff2)format("woff2"),url(/assets/inter-tight-latin-ext-700-normal-CrlzIQ10.woff)format("woff");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 Tight;font-style:normal;font-display:swap;font-weight:700;src:url(/assets/inter-tight-latin-700-normal-BZKd_v_8.woff2)format("woff2"),url(/assets/inter-tight-latin-700-normal-DvYAVZQd.woff)format("woff");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}.membership-page{padding-top:28px;padding-bottom:40px}.membership-back{min-height:44px;color:var(--color-ink-2);align-items:center;margin-bottom:24px;font-size:14px;display:inline-flex}.membership-brand{flex-wrap:wrap;align-items:center;gap:10px;margin-bottom:32px;font-size:14px;display:flex}.membership-test{border:1px solid var(--color-line);color:var(--color-ink-2);border-radius:5px;padding:3px 8px;font-size:12px}.membership-intro{color:var(--color-ink-2);max-width:500px;margin:16px 0 28px;font-size:16px;line-height:1.65}.membership-benefits{gap:22px;margin:0;padding:0 0 30px;list-style:none;display:grid}.membership-benefits li{gap:14px;display:flex}.membership-benefits li>span{color:var(--color-ink-2);margin-top:2px}.membership-benefits strong{font-size:15px;font-weight:500}.membership-benefits p{color:var(--color-ink-2);margin-top:4px;font-size:14px;line-height:1.55}.membership-plans{grid-template-columns:1fr 1fr;gap:12px;margin-bottom:20px;display:grid}.membership-plan{text-align:left;border:1px solid var(--color-line);background:var(--color-card);border-radius:6px;padding:20px;transition:border-color .16s,background .16s}.membership-plan.is-selected{border-color:var(--color-ink);box-shadow:inset 0 0 0 1px var(--color-ink)}.membership-plan:hover:not(:disabled){border-color:var(--color-ink-2)}.membership-plan-name{margin-bottom:12px;font-size:14px;display:block}.membership-price{font-variant-numeric:tabular-nums;letter-spacing:-.04em;font-size:28px;font-weight:500;display:block}.membership-price>span{letter-spacing:0;color:var(--color-ink-2);font-size:14px;font-weight:400}.membership-plan-note{color:var(--color-ink-2);margin-top:8px;font-size:12px;line-height:1.5;display:block}.membership-cta{width:100%}.membership-terms{color:var(--color-ink-2);text-align:center;max-width:440px;margin:12px auto 0;font-size:12px;line-height:1.65}.membership-free{min-height:44px;color:var(--color-ink-2);text-underline-offset:4px;margin:12px auto 20px;font-size:14px;text-decoration:underline;display:block}.membership-detail{border-block:1px solid var(--color-line);flex-wrap:wrap;justify-content:space-between;gap:8px;padding:20px 0;font-size:14px;display:flex}.membership-detail>span+span{color:var(--color-ink-2)}.membership-actions{flex-wrap:wrap;gap:12px;margin:24px 0;display:flex}.membership-note,.membership-error{margin:16px 0;font-size:14px;line-height:1.6}.membership-error{color:var(--color-bad)}.membership-footer{border-top:1px solid var(--color-line);color:var(--color-ink-3);margin-top:32px;padding-top:24px;font-size:12px}.membership-footer a{text-underline-offset:3px;text-decoration:underline}.membership-return{flex-direction:column;justify-content:center;align-items:flex-start;gap:24px;max-width:560px;min-height:100dvh;margin:auto;padding:40px 24px;display:flex}.membership-return p{color:var(--color-ink-2);line-height:1.6}.membership-settings{text-align:left;justify-content:space-between;align-items:center;gap:16px;width:100%;min-height:68px;display:flex}.membership-settings strong{font-size:15px;font-weight:500}.membership-settings>span>span{color:var(--color-ink-2);margin-top:4px;font-size:13px;display:block}@media (width<=420px){.membership-plan{padding:16px 12px}.membership-price{font-size:25px}.membership-brand{margin-bottom:24px}}@media (prefers-reduced-motion:reduce){.membership-plan{transition:none}}.chat-surface{flex-direction:column;min-width:0;height:100%;min-height:0;display:flex;position:relative}.chat-page{height:calc(100% - var(--kb,0px));transition:height .25s var(--kb-ease,ease)}.chat-header{border-bottom:1px solid var(--color-line);flex-shrink:0;justify-content:space-between;align-items:center;gap:12px;padding:16px 20px;display:flex}.chat-header-title{font-size:14px;font-weight:600}.chat-header-detail{color:var(--color-ink-3);margin-top:2px;font-size:12px}.chat-scroll{flex:1;min-height:0;scroll-padding:24px;overflow-y:auto}.chat-thread{flex-direction:column;gap:28px;width:100%;max-width:760px;margin:0 auto;padding:24px 20px;display:flex}.chat-welcome{padding:clamp(12px,6vh,64px) 0 16px}.chat-welcome h1{margin-top:12px;font-size:clamp(28px,5vw,38px);line-height:1.12}.chat-welcome p{color:var(--color-ink-2);margin-top:14px;font-size:14px;line-height:1.6}.chat-starters{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin-top:28px;display:grid}.chat-starter{text-align:left;border:1px solid var(--color-line);background:var(--color-card);border-radius:14px;padding:14px;font-size:13px;line-height:1.5;transition:border-color .15s}.chat-starter:hover{border-color:var(--color-ink-3)}.chat-user{background:color-mix(in srgb, var(--color-ink) 6%, var(--color-card));white-space:pre-wrap;overflow-wrap:anywhere;border-radius:20px 20px 5px;align-self:flex-end;max-width:88%;padding:11px 16px;font-size:15px}.chat-answer{overflow-wrap:anywhere;width:100%;min-width:0;font-size:15px;line-height:1.75}.chat-content>:first-child{margin-top:0}.chat-content>:last-child{margin-bottom:0}.chat-content p{white-space:pre-wrap;margin:12px 0}.chat-content h3{margin:20px 0 8px;font-size:1em;font-weight:600;line-height:1.5}.chat-content ul,.chat-content ol{margin:12px 0;padding-left:24px}.chat-content ul{list-style:outside}.chat-content ol{list-style:decimal}.chat-content li{margin:6px 0;padding-left:3px}.chat-content .math-block{margin:16px 0}.chat-code{border:1px solid var(--color-line);background:var(--color-card);border-radius:14px;margin:16px 0;overflow:hidden}.chat-code-language{border-bottom:1px solid var(--color-line);font:11px var(--font-mono);color:var(--color-ink-3);padding:7px 14px}.chat-code pre{white-space:pre;padding:14px;font-size:12px;line-height:1.6;overflow-x:auto}.chat-diagram{border:1px solid var(--color-line);background:var(--color-card);border-radius:18px;margin:20px 0;padding:16px}.chat-diagram h3{margin:0 0 12px}.chat-diagram .lesson-figure{max-width:380px;margin-inline:auto}.chat-actions{flex-wrap:wrap;align-items:center;gap:8px;margin-top:16px;display:flex}.chat-jump{text-align:left;border:1px solid var(--color-line);color:var(--color-ink-2);border-radius:10px;padding:8px 11px;font-size:12px;line-height:1.4}.chat-icon-button{width:36px;height:36px;color:var(--color-ink-3);border-radius:50%;flex-shrink:0;place-items:center;transition:background .15s;display:inline-grid}.chat-icon-button:hover{background:color-mix(in srgb, var(--color-ink) 6%, transparent)}.chat-icon-button[aria-pressed=true]{color:var(--color-ink);background:color-mix(in srgb, var(--color-ink) 8%, transparent)}.chat-activity{color:var(--color-ink-3);font-size:12px;line-height:1.5}.chat-activity summary{cursor:pointer;padding:6px 0}.chat-activity ol{gap:8px;padding:8px 0;display:grid}.chat-activity li{align-items:center;gap:8px;display:flex}.chat-progress{min-height:24px;color:var(--color-ink-2);align-items:center;gap:9px;font-size:13px;display:flex}.chat-spinner{border:1.5px solid var(--color-line-2);border-top-color:var(--color-ink-2);border-radius:50%;flex-shrink:0;width:13px;height:13px;animation:.9s linear infinite chat-spin;display:inline-block}@keyframes chat-spin{to{transform:rotate(360deg)}}.chat-composer-wrap{width:100%;max-width:760px;padding:10px 16px max(12px, env(safe-area-inset-bottom));background:var(--color-card);flex-shrink:0;margin:0 auto;position:relative}.chat-page .chat-composer-wrap{background:var(--color-paper)}.chat-composer-wrap[data-keyboard=true]{padding-bottom:10px}.chat-suggestions{scrollbar-width:none;gap:6px;margin-bottom:10px;display:flex;overflow-x:auto}.chat-suggestions::-webkit-scrollbar{display:none}.chat-suggestions button{border:1px solid var(--color-line);max-width:90%;color:var(--color-ink-2);text-overflow:ellipsis;white-space:nowrap;border-radius:20px;flex-shrink:0;padding:8px 12px;font-size:12px;overflow:hidden}.chat-composer{border:1px solid var(--color-line-2);background:var(--color-card);border-radius:25px;align-items:flex-end;gap:8px;padding:7px 7px 7px 16px;transition:border-color .15s,box-shadow .15s;display:flex;box-shadow:0 2px 8px #00000006}.chat-composer:focus-within{border-color:var(--color-ink-3);box-shadow:0 0 0 3px color-mix(in srgb, var(--color-accent) 10%, transparent)}.chat-composer textarea{resize:none;min-width:0;max-height:min(128px,24dvh);box-shadow:none;-webkit-appearance:none;background:0 0;border:0;border-radius:0;flex:1;padding:9px 0;font-size:16px;line-height:1.4;outline:none!important}.chat-send{background:var(--color-ink);width:40px;height:40px;color:var(--color-on-ink);border-radius:50%;flex-shrink:0;place-items:center;transition:opacity .15s,transform .15s;display:grid}.chat-send:active{transform:scale(.94)}.chat-send:disabled{opacity:.25}.chat-composer-note{text-align:center;color:var(--color-ink-3);margin-top:7px;font-size:11px}.chat-latest{border:1px solid var(--color-line);background:var(--color-card);box-shadow:var(--shadow-lift);white-space:nowrap;border-radius:20px;align-self:center;padding:8px 14px;font-size:12px;position:absolute;bottom:calc(100% + 10px);left:50%;transform:translate(-50%)}@media (width>=768px){.chat-page .chat-thread{padding:32px}.chat-page .chat-answer{font-size:16px}.chat-page .chat-composer-wrap{padding-inline:28px;padding-bottom:20px}}@media (width<=767px){.chat-panel{bottom:var(--kb,0px)!important;height:calc(92dvh - var(--kb,0px))!important}.chat-icon-button{width:40px;height:40px}}@media (prefers-reduced-motion:reduce){.chat-spinner{animation:none}.chat-page,.chat-composer{transition:none}}