/* EasyTutorGuide Frontend · ONE shared stylesheet for all 14 courses. */
:root{color-scheme:light;--paper:#f7faff;--panel:#fff;--ink:#1c2e48;--muted:#54657c;--border:#dce6f1;--soft:#edf5ff;--shadow:0 12px 42px rgba(22,48,78,.08);--reading-scale:1;--course-accent:#278fd3}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:130px}body{margin:0;min-width:0;max-width:100%;overflow-x:clip;background:linear-gradient(145deg,#f9fcff,#f4f7ff 48%,#f8fbff);color:var(--ink);font:400 16px/1.65 system-ui,-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;overflow-wrap:anywhere}img,svg{max-width:100%}a{color:#155b9b;text-underline-offset:.2em;transition:color .18s,background .18s,transform .18s}a:hover{color:#6a3dc5}button,select,input{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,summary:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #f49e26;outline-offset:3px}.ico{width:21px;height:21px;flex:none;display:inline-block;vertical-align:middle;stroke:currentColor;fill:none}.skip{position:absolute;top:-90px;inset-inline-start:10px;z-index:3000;background:#fff;padding:10px;border-radius:9px}.skip:focus{top:12px}.reading-bar{position:fixed;inset:0 auto auto 0;height:4px;width:0;background:linear-gradient(90deg,#20b8dc,#8b69ea,#f7a4e1);z-index:9999;transition:width .12s}
.site-header{position:sticky;top:0;z-index:150;background:rgba(255,255,255,.94);backdrop-filter:blur(16px);border-bottom:1px solid var(--border)}.header-inner{max-width:1380px;margin:auto;min-height:67px;padding:7px clamp(14px,3vw,32px);display:flex;justify-content:space-between;align-items:center;gap:15px}.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);min-width:0}.brand img{width:44px;height:44px;border-radius:14px;flex:none;box-shadow:0 3px 12px #4d56c424}.brand span{display:grid;min-width:0}.brand strong{font-size:1.06rem;line-height:1.15;letter-spacing:-.6px}.brand small{font-size:.68rem;color:var(--muted);line-height:1.45}.top-links{display:flex;gap:0;align-items:center;flex-wrap:wrap;justify-content:end}.top-links a,.mobile-nav a{padding:7px 9px;border-radius:9px;font-weight:620;font-size:.8rem;text-decoration:none;color:var(--ink)}.top-links a:hover,.mobile-nav a:hover{background:#e7f3ff;color:#0a58a2}.icon-btn{border:1px solid var(--border);border-radius:11px;background:var(--panel);padding:8px;display:inline-grid;place-items:center;min-height:40px;min-width:40px}.mobile-nav-btn{display:none}.mobile-nav{padding:10px 15px 18px;border-top:1px solid var(--border);background:var(--panel);max-height:65vh;overflow:auto}.mobile-nav:not([hidden]){display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px}.mobile-nav a{padding:10px}
.page-shell{max-width:1350px;margin:0 auto;padding:0 clamp(12px,2.8vw,30px)}.toolbar{position:relative;display:flex;flex-wrap:wrap;align-items:center;gap:7px;padding:13px 0 6px;border-bottom:1px solid var(--border)}.tool-button{border:1px solid var(--border);border-radius:12px;background:var(--panel);box-shadow:0 2px 9px #1e45600b;display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:40px;padding:7px 12px;color:var(--ink);font-weight:700;font-size:.86rem}.tool-button:hover,.icon-btn:hover{background:var(--soft);border-color:var(--course-accent)}.translate-label{display:inline-flex;align-items:center;gap:6px;font-size:.82rem;font-weight:700;color:var(--muted)}.translate-label select{background:var(--panel);color:var(--ink);border:1px solid var(--border);border-radius:9px;padding:8px 4px;min-height:40px;max-width:150px}.toolbar-feedback{color:var(--course-accent);font-size:.79rem;min-width:0}.breadcrumbs{margin:13px 0 17px;display:flex;flex-wrap:wrap;align-items:center;gap:7px;color:var(--muted);font-size:.79rem}.breadcrumbs a{text-decoration:none;font-weight:600}.main-layout{display:grid;grid-template-columns:minmax(0,1fr) 210px;gap:25px;align-items:start}.lesson-main{min-width:0;max-width:100%}
.chapter-top,.course-hero,.library-hero{overflow:hidden;position:relative;border:1px solid #dce7f6;background:linear-gradient(116deg,#f6fdff,#edf2ff 55%,#ffeff9);box-shadow:var(--shadow);border-radius:25px;padding:clamp(23px,3.5vw,42px)}.chapter-top:before,.course-hero:before,.library-hero:before{content:"";position:absolute;inset-inline-end:-90px;top:-125px;height:290px;width:290px;border-radius:50%;background:radial-gradient(circle,color-mix(in srgb,var(--course-accent) 22%,transparent),transparent 72%);pointer-events:none}.eyebrow{text-transform:uppercase;letter-spacing:.11em;font-weight:820;font-size:.75rem;color:var(--course-accent)}h1,h2,h3{line-height:1.24;letter-spacing:-.025em}h1{font-size:clamp(1.85rem,3.5vw,3rem);margin:10px 0 12px}h2{font-size:clamp(1.28rem,2vw,1.55rem)}h3{font-size:1.1rem}.lead{font-size:clamp(1.02rem,1.55vw,1.2rem);color:#425879;line-height:1.6;max-width:850px}.chapter-meta,.course-stats{display:flex;flex-wrap:wrap;gap:9px 17px;margin-top:19px;font-size:.82rem;color:#4b647e}.chapter-meta span{display:inline-flex;align-items:center;gap:5px}.chapter-meta .ico{width:17px;height:17px}.progress-line{margin-top:20px;height:7px;border-radius:8px;background:#dfeafa;overflow:hidden}.progress-line span{display:block;height:100%;background:linear-gradient(90deg,var(--course-accent),#a278d6)}.disclaimer{margin:18px 0;border:1px solid #cfe4d9;border-radius:14px;background:#f2fbf5;padding:11px 16px;color:#355c49}.disclaimer summary{display:flex;gap:9px;align-items:center;cursor:pointer;font-weight:760}.disclaimer p{font-size:.87rem;line-height:1.7}
.pager{display:grid;grid-template-columns:1fr auto 1fr;gap:8px;margin:14px 0}.pager a{display:inline-flex;align-items:center;justify-content:center;gap:6px;border:1px solid var(--border);border-radius:11px;min-height:46px;background:var(--panel);text-align:center;padding:8px;font-weight:700;font-size:.83rem;text-decoration:none}.pager a:first-child,.pager a:last-child{justify-self:stretch}.pager a:hover{background:var(--soft);border-color:var(--course-accent);transform:translateY(-2px)}.pager .primary,.cta{color:#fff;background:linear-gradient(110deg,var(--course-accent),#776ada);border-color:transparent}.pager .primary:hover,.cta:hover{color:#fff;background:linear-gradient(110deg,#126f9d,#7157b3)}
.lesson-article{background:var(--panel);border:1px solid var(--border);box-shadow:var(--shadow);padding:clamp(18px,3.2vw,40px);border-radius:22px;min-width:0;font-size:calc(1.04rem * var(--reading-scale));line-height:1.78}.lesson-article>section{scroll-margin-top:135px;margin-bottom:42px}.lesson-article>section:last-child{margin-bottom:8px}.lesson-article h2{border-bottom:1px solid var(--border);padding-bottom:10px;margin:18px 0 20px;color:#254665}.lesson-article h3{color:#284e71}.lesson-article p{margin:12px 0;max-width:100%;text-wrap:pretty}.lesson-article li{margin-bottom:9px}.outcomes{padding-inline-start:1.5rem}.definition-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}.definition-grid>div{min-width:0;background:linear-gradient(145deg,#f8fbff,#f0f7ff);border:1px solid #dce6f4;border-radius:12px;padding:16px}.definition-grid h3{margin:0 0 6px;color:var(--course-accent);font-size:1rem}.definition-grid p{font-size:.86em;margin:0}.example{padding:clamp(13px,2vw,23px);border:1px solid var(--border);border-radius:17px;margin:19px 0;background:linear-gradient(145deg,#fff,#fcfdff)}.example h3{margin:8px 0 12px}.example ol{padding-inline-start:24px}.example-kicker{display:inline-flex;background:#e3f2fa;border:1px solid #c5e5f5;color:#125b85;border-radius:999px;font-size:.7em;font-weight:800;letter-spacing:.03em;padding:4px 12px}.expected,.note{border-inline-start:4px solid #37a78e;background:#edf9f4;padding:12px;border-radius:8px;color:#244d44}.code-block{max-width:100%;overflow-x:auto;overscroll-behavior-x:contain;white-space:pre;direction:ltr;text-align:left;background:#102a31;color:#e8fff4;padding:20px;border-radius:13px;border:1px solid #315056;font:500 .87em/1.75 ui-monospace,SFMono-Regular,Consolas,'Liberation Mono',monospace;tab-size:2;word-break:normal;overflow-wrap:normal}.code-block code{white-space:pre;word-break:normal;overflow-wrap:normal}.output{border-radius:12px;background:#e6f8ec;border:1px solid #b6e6c7;color:#174a36;padding:12px 15px}.output strong{display:block;font-size:.9em}.output p{font-size:.89em;margin:5px 0}
.questions-head{display:flex;align-items:center;justify-content:space-between;gap:14px}.questions-head h2{margin:5px 0!important}.questions-head p{font-size:.93em;color:var(--muted)}.count-pill{background:#e8f7fc;color:#106b87;border:1px solid #c4e9f5;border-radius:99px;padding:6px 10px;white-space:nowrap;font-weight:750;font-size:.8em}.qa{border:1px solid var(--border);border-radius:12px;overflow:hidden;margin:9px 0;background:#fff}.qa summary{cursor:pointer;display:flex;align-items:center;gap:10px;padding:13px 15px;font-weight:700;line-height:1.4;list-style:none}.qa summary::-webkit-details-marker{display:none}.qa:hover{border-color:#a8d4ed}.qa-num{display:grid;place-items:center;flex:none;width:32px;height:32px;border-radius:9px;background:#eaf4ff;color:#2e6896;font-size:.75em}.qa-chevron{margin-inline-start:auto;transition:transform .18s}.qa[open] .qa-chevron{transform:rotate(90deg)}.answer{border-top:1px solid var(--border);padding:10px 15px 14px;background:#f6faff}.answer p{margin:9px 0}.answer p:nth-child(2){font-size:.9em;color:#4f647b}.toc{position:sticky;top:105px;border:1px solid var(--border);border-radius:17px;background:var(--panel);padding:17px;box-shadow:var(--shadow);display:grid;gap:2px;min-width:0}.toc strong{font-size:.85rem;margin-bottom:7px}.toc a{display:block;padding:8px 9px;border-radius:8px;text-decoration:none;font-size:.81rem;color:var(--muted)}.toc a:hover{color:var(--course-accent);background:var(--soft)}.toc-chapters{display:inline-flex;align-items:center;gap:8px;justify-content:center;margin-top:12px;color:var(--course-accent);background:#eff7ff;border:1px solid var(--border);padding:9px;border-radius:11px;font-size:.84rem;font-weight:700}.next-preview{display:flex;align-items:center;flex-wrap:wrap;gap:5px 14px;background:#ecf7ff;border:1px solid #d5eafa;border-radius:13px;padding:14px 19px;margin:18px 0}.next-preview span{font-size:.8rem;color:#537089}.next-preview strong{font-size:.95rem}.read-more{background:linear-gradient(120deg,#eefaff,#f4eeff);border:1px solid #dfe5f8;border-radius:19px;margin:30px 0;padding:22px}.read-more h2{margin-top:0}.read-more p{color:var(--muted)}.read-more a{display:inline-flex;align-items:center;gap:7px;font-weight:800}
.course-landing,.library-main{padding-bottom:36px}.course-hero,.library-hero{padding:clamp(24px,4vw,55px);margin-bottom:20px}.course-stats span{background:rgba(255,255,255,.8);border:1px solid #d7e9f4;padding:5px 10px;border-radius:99px;color:#3b6786}.cta{display:inline-flex;align-items:center;gap:9px;padding:13px 24px;margin-top:23px;border-radius:12px;font-weight:760;text-decoration:none;box-shadow:0 9px 16px #295b9325}.level-jump{display:flex;flex-wrap:wrap;gap:10px;margin:22px 0}.level-jump a{padding:9px 19px;border:1px solid #c9ddef;border-radius:11px;background:#fff;text-decoration:none;font-weight:750}.level-jump a:hover{background:var(--soft)}.overview-level{margin-top:25px;background:var(--panel);border:1px solid var(--border);border-radius:20px;padding:clamp(15px,2vw,26px)}.overview-level h2{margin:0}.overview-level small{font-weight:500;color:var(--muted);font-size:.73em}.overview-level>p{color:var(--muted);font-size:.86rem}.overview-lessons{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:9px}.overview-lesson{display:flex;align-items:center;gap:10px;min-width:0;padding:11px 12px;background:#f7fbff;border:1px solid #e0eaf6;border-radius:11px;text-decoration:none;font-size:.87rem;line-height:1.4;font-weight:630;color:var(--ink)}.overview-lesson:hover{background:#eaf5ff;border-color:var(--course-accent);transform:translateY(-1px)}.overview-lesson .ico{margin-inline-start:auto;color:var(--course-accent)}.chapter-n{display:inline-grid;place-items:center;flex:none;width:32px;height:29px;border-radius:8px;background:#e4f0fd;color:#24639a;font-size:.75em;font-weight:800}.library-main{padding-top:14px}.library-count{margin-top:15px;font-size:.9rem;color:#4b647e}.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;margin:22px 0}.course-card{position:relative;overflow:hidden;display:flex;flex-direction:column;min-height:245px;background:linear-gradient(139deg,#fff,#f5fbff 50%,#f4f0ff);border:1px solid var(--border);border-top:5px solid var(--card-accent);border-radius:19px;padding:22px;text-decoration:none;color:var(--ink);box-shadow:var(--shadow)}.course-card:hover{border-color:var(--card-accent);transform:translateY(-4px);box-shadow:0 18px 37px rgba(40,55,99,.16)}.card-icon{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:#e7f3ff;color:var(--card-accent);margin-bottom:12px}.course-card h2{font-size:1.4rem;margin:8px 0}.course-card p{font-size:.91rem;color:var(--muted);line-height:1.55;margin:0 0 22px}.card-bottom{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-top:auto;border-top:1px solid var(--border);padding-top:13px;font-size:.81rem;font-weight:800}.card-bottom span:last-child{display:flex;align-items:center;gap:5px;color:var(--card-accent)}
.drawer-backdrop{position:fixed;inset:0;background:#101b2d80;z-index:350}.drawer{position:fixed;z-index:351;top:0;bottom:0;inset-inline-start:0;width:min(385px,93vw);transform:translateX(-108%);transition:transform .24s ease;background:var(--panel);box-shadow:15px 0 30px #12203740;display:flex;flex-direction:column;min-height:0;overflow:hidden}.drawer.is-open{transform:translateX(0)}.drawer-head{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:17px;border-bottom:1px solid var(--border)}.drawer-head strong,.drawer-head small{display:block}.drawer-head strong{font-size:1.12rem}.drawer-head small{font-size:.73rem;color:var(--muted)}.close-red{color:#b4273b;border-color:#ffd2d5;background:#fff2f3}.close-red:hover{color:#fff;background:#d83e55}.search-field{display:flex;align-items:center;gap:7px;margin:12px 14px;padding:0 11px;border-radius:11px;background:var(--soft);border:1px solid var(--border)}.search-field input{border:none;outline:0;background:transparent;color:var(--ink);width:100%;min-width:0;padding:13px 2px;font-size:.88rem}.drawer nav{display:block;overflow:auto;padding:0 13px 30px;overscroll-behavior:contain}.menu-group{margin-top:20px}.menu-group h3{font-size:.86rem;color:var(--course-accent);padding:0 9px;margin:0 0 8px}.menu-group h3 small{font-weight:500;color:var(--muted)}.chapter-link{display:flex;align-items:center;gap:10px;min-width:0;text-decoration:none;font-size:.81rem;line-height:1.5;padding:9px 11px;border-radius:9px;color:var(--ink)}.chapter-link:hover{background:#e6f3ff}.chapter-link.active{background:#e8f3ff;border-inline-start:4px solid var(--course-accent);font-weight:800}.overview-link{font-weight:800;color:#225e9a}.empty-search{padding:15px;color:var(--muted)}.back-to-top{position:fixed;bottom:18px;inset-inline-end:18px;z-index:200;display:grid;place-items:center;border:1px solid #ccdaee;background:var(--panel);color:var(--course-accent);border-radius:14px;width:47px;height:47px;box-shadow:var(--shadow);opacity:0;pointer-events:none;transition:opacity .2s}.back-to-top.visible{opacity:1;pointer-events:auto}
.footer{border-top:1px solid #d9e8f5;background:linear-gradient(110deg,#eaf7ff,#f5f3ff,#fff4fb);padding:36px clamp(14px,4vw,40px) 21px;margin-top:30px;min-width:0}.footer-grid{max-width:1260px;margin:auto;display:grid;grid-template-columns:1.7fr 1fr 1fr;gap:clamp(14px,3vw,45px)}.footer-grid>div{min-width:0;display:flex;flex-direction:column;align-items:flex-start}.footer-grid p{font-size:.87rem;max-width:370px;color:var(--muted)}.footer-grid a{display:block;text-decoration:none;font-size:.85rem;margin:3px 0}.footer-grid a:hover{color:#7950d5;transform:translateX(2px)}.footer-grid h3{margin:0 0 10px}.footer-brand{display:flex!important;gap:9px;align-items:center}.footer-brand img{width:54px;height:54px}.rainbow-brand{display:block!important;white-space:normal;font-weight:900;line-height:1.2;font-size:clamp(.85rem,1.5vw,1.21rem)}.brand-easy{color:#168cc5}.brand-tutor{color:#6f61ce}.brand-guide{color:#d34d95}.brand-dot{color:#267b70}.footer-brand:hover .rainbow-brand{animation:brand-pulse .8s ease-in-out 1}@keyframes brand-pulse{0%,100%{filter:saturate(1)}50%{filter:saturate(1.8);text-shadow:0 0 5px #69b6ff}}.social-icons{display:flex;flex-wrap:wrap;gap:4px;margin-top:9px}.footer-grid .social-icons a{display:grid;place-items:center;width:35px;height:35px;border-radius:9px;border:1px solid #d0dfeb;background:#fff;margin:1px}.social-icons .ico{width:19px;height:19px}.social-icons a:hover{background:#e4efff}.footer-policies{max-width:1260px;margin:25px auto 12px;display:flex;flex-wrap:wrap;justify-content:center;gap:12px;border-top:1px solid #d6e6f3;padding-top:16px}.footer-policies a{font-weight:730;font-size:.85rem}.copyright{text-align:center;color:var(--muted);font-size:.76rem}
/* Night view retains text contrast and overrides all light component surfaces. */
body.night{color-scheme:dark;--paper:#17202e;--panel:#1e2b3d;--ink:#f0f6ff;--muted:#b1c4da;--border:#395068;--soft:#2b4157;--shadow:0 12px 35px rgba(0,0,0,.24);background:linear-gradient(140deg,#152033,#1a2340 45%,#252032)}body.night .site-header{background:rgba(26,36,54,.96)}body.night .chapter-top,body.night .course-hero,body.night .library-hero{background:linear-gradient(120deg,#253b50,#242f57,#38314c);border-color:#4a5b70}body.night .lead,body.night .chapter-meta,body.night .breadcrumbs,body.night .course-stats,body.night .definition-grid p{color:var(--muted)}body.night .lesson-article h2,body.night .lesson-article h3{color:#b7e7ff}body.night .disclaimer{background:#213f38;border-color:#3a7262;color:#d9fcef}body.night .example,body.night .qa{background:#243347}body.night .definition-grid>div,body.night .overview-lesson{background:#273c53;border-color:#3f5870}body.night .expected,body.night .note,body.night .output{background:#20433e;border-color:#2b7e65;color:#d7fff1}body.night .answer{background:#283d55}body.night .course-card{background:linear-gradient(125deg,#24354c,#2b3052)}body.night .read-more,body.night .next-preview,body.night .footer{background:linear-gradient(120deg,#26394c,#2a2c50)}body.night .qa-num,body.night .chapter-n{background:#334f6b;color:#d6eeff}body.night .example-kicker,body.night .count-pill{background:#28506b;color:#c9f0ff;border-color:#3d7294}body.night .code-block{background:#101f29;color:#e8fff4}body.night .pager .primary{background:linear-gradient(110deg,#2a719b,#615ab5);color:#fff}body.night .footer-grid .social-icons a{background:#2c4260}body.night .footer-policies{border-color:var(--border)}body.night .course-stats span{background:#2c425f;border-color:#4a6583}body.night .search-field{background:var(--soft)}body.night .toolbar-feedback{color:#a1e0ff}

@media(max-width:1160px){.top-links{display:none}.mobile-nav-btn{display:inline-grid}.main-layout{grid-template-columns:minmax(0,1fr) 190px}.toc{padding:11px}}
@media(max-width:850px){.main-layout{grid-template-columns:minmax(0,1fr)}.toc{display:none}.course-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.definition-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.header-inner{min-height:61px}}
@media(max-width:620px){.page-shell{padding:0 10px}.header-inner{padding:6px 11px}.brand img{height:38px;width:38px;border-radius:12px}.brand strong{font-size:1rem}.brand small{font-size:.65rem}.chapter-top,.course-hero,.library-hero{padding:21px 17px;border-radius:17px}.toolbar{gap:5px;padding:9px 0}.tool-button{padding:7px 8px;min-width:40px}.toolbar .desktop-label{display:none}.translate-label{font-size:.75rem}.translate-label select{max-width:118px}.breadcrumbs{font-size:.74rem;line-height:1.4}.lesson-article{padding:16px 13px;font-size:calc(1rem * var(--reading-scale));border-radius:16px}.definition-grid{grid-template-columns:minmax(0,1fr)}.example{padding:13px}.code-block{font-size:.78em;padding:13px}.qa summary{font-size:.9em;padding:11px 9px}.qa-num{height:27px;width:27px}.pager{gap:5px}.pager a{padding:6px;font-size:.73rem;min-height:45px}.overview-lessons,.course-grid{grid-template-columns:minmax(0,1fr)}.course-card{min-height:210px}.footer{padding:28px 10px 19px}.footer-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}.footer-grid h3{font-size:.84rem}.footer-grid a{font-size:.72rem;line-height:1.4}.footer-grid p{font-size:.69rem;line-height:1.45}.footer-brand{flex-wrap:wrap;gap:4px}.footer-brand img{height:39px;width:39px}.rainbow-brand{font-size:.7rem;word-break:break-word}.social-icons{gap:2px}.footer-grid .social-icons a{height:27px;width:27px;border-radius:7px}.social-icons .ico{height:15px;width:15px}.footer-policies a{font-size:.75rem}.copyright{font-size:.7rem}.chapter-meta{font-size:.76rem}.course-stats span{font-size:.76rem}.next-preview{font-size:.86rem}}
@media(max-width:350px){.toolbar .dir-label{display:none}.translate-label{display:flex;flex-basis:100%;justify-content:flex-start}.brand strong{font-size:.91rem}.chapter-top h1{font-size:1.72rem}.pager .pager-menu{font-size:0}.pager .pager-menu .ico{width:20px;height:20px}.questions-head{display:block}.count-pill{display:inline-flex;margin-bottom:12px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation-duration:.01ms!important;transition-duration:.01ms!important}.footer-brand:hover .rainbow-brand{animation:none}}
.mobile-nav-btn.is-open{color:#ba2937;background:#ffedf0;border-color:#ffccd6}

/* Ensure dark-mode buttons, links, and explanatory text remain readable. */
body.night a:not(.primary):not(.cta){color:#b9deff}
body.night .tool-button,body.night .icon-btn,body.night .translate-label select,body.night .level-jump a,body.night .toc-chapters,body.night .pager a:not(.primary),body.night .back-to-top{color:#f2f7ff;background:#263b52;border-color:#536c85}
body.night .tool-button:hover,body.night .icon-btn:hover,body.night .level-jump a:hover,body.night .toc-chapters:hover,body.night .pager a:not(.primary):hover{background:#365575;color:white}
body.night .answer p:nth-child(2),body.night .next-preview span,body.night .course-stats span,body.night .overview-level>p,body.night .course-card p{color:#c4d5e8}
body.night .eyebrow,body.night .definition-grid h3,body.night .overview-lesson .ico{color:#a9e6ff}
body.night .chapter-link:hover,body.night .chapter-link.active{background:#335477;color:#f2f9ff}
body.night .close-red{background:#572937;border-color:#ae5264;color:#fff}
body.night .close-red:hover{background:#ce354d;color:#fff}
body.night .qa summary:hover{background:#30435b}
body.night .course-card:hover{border-color:#aad4fa}
/* Container-specific colours remain accessible when switched to night view. */
body.night .course-card .card-bottom span:last-child{color:#aadaff}
body.night .output,body.night .expected,body.night .note{color:#e2fff3}
body.night .footer,body.night .footer-grid p{color:#d5e2f3}
body.night .footer-grid .social-icons a{color:#e8f5ff}
/* Reflow the UI rather than moving the page sideways on LTR/RTL and at 200% zoom. */
.page-shell,.main-layout,.lesson-article,.example,.course-grid,.overview-lessons,.footer-grid,.course-card,.overview-lesson{min-width:0}
.long-content,pre,table{max-width:100%}
table{display:block;overflow-x:auto}
@media (max-width:420px){.footer-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.rainbow-brand{overflow-wrap:anywhere}.header-inner{min-width:0}}

/* 2026-10-24 UI update: strong icon contrast and verified brand logo, no RTL toggle. */
html{direction:ltr}body{direction:ltr}
.brand img{width:120px;height:61px;object-fit:contain;object-position:center;background:#fff;border-radius:13px;box-shadow:0 3px 12px rgba(21,54,90,.12);padding:3px;display:block}
.brand span{display:none}
.footer-brand{display:flex!important;flex-direction:column;align-items:flex-start;gap:5px}
.footer-brand img{width:152px;height:80px;object-fit:contain;background:#fff;padding:5px;border-radius:16px;border:1px solid #d5e2ef;box-shadow:0 3px 12px #244c751c}
.footer-brand .rainbow-brand{display:block!important}
/* High-contrast dark glyphs on an opaque white control surface in both themes. */
.tool-button,.icon-btn,.back-to-top,.drawer-head button,.social-icons a,
body.night .tool-button,body.night .icon-btn,body.night .back-to-top,
body.night .drawer-head button,body.night .social-icons a {
 background:#fff!important;color:#163b62!important;border:1.5px solid #b2c8de!important;
 box-shadow:0 2px 8px rgba(16,48,84,.11);opacity:1;
}
.tool-button .ico,.icon-btn .ico,.back-to-top .ico,.drawer-head button .ico,
.social-icons .ico{width:21px;height:21px;stroke:currentColor;stroke-width:2.15;opacity:1;visibility:visible}
.tool-button:hover,.icon-btn:hover,.back-to-top:hover,.drawer-head button:hover,.social-icons a:hover,
body.night .tool-button:hover,body.night .icon-btn:hover,body.night .back-to-top:hover,
body.night .drawer-head button:hover,body.night .social-icons a:hover {
 background:#e3f3ff!important;border-color:#1685c4!important;color:#094a85!important;
}
.drawer-head [data-close-drawer], body.night .drawer-head [data-close-drawer]{color:#b71e3a!important;background:#fff4f5!important;border-color:#e79cad!important}
/* Distinguishable social buttons with white surfaces */
.social-icons a[href*="facebook"]{color:#155ac3!important}.social-icons a[href*="instagram"]{color:#ac2e8e!important}
.social-icons a[href*="youtube"]{color:#bb2028!important}.social-icons a[href*="x.com"]{color:#192b3e!important}
.social-icons a[href*="tiktok"]{color:#253347!important}.social-icons a[href*="t.me"]{color:#177aaa!important}
.social-icons a[href^="mailto:"]{color:#297746!important}
.translate-label{flex-wrap:wrap;gap:5px}.google-credit{display:inline-flex;align-items:center;flex-wrap:wrap;gap:4px;
 border:1px solid #c4d9ef;border-radius:9px;background:#fff;padding:6px 9px;color:#254e76;font-size:.72rem;line-height:1.3}
.google-credit a{color:#0b59a3;font-weight:800;text-decoration:underline}
body.night .google-credit{background:#fff;color:#254e76}
body.night .translate-label select{background:#fff;color:#153957;border-color:#afc6df}
body.night .brand img,body.night .footer-brand img{background:#fff}
@media(max-width:650px){.brand img{width:96px;height:54px}.footer-brand img{width:125px;height:69px}.toolbar{row-gap:10px}.google-credit{font-size:.68rem}}
@media(prefers-reduced-motion:reduce){.footer-brand:hover .rainbow-brand{animation:none!important}}

/* Content-only refinements; no redesign of Python layout. */
#examples pre.code-block, #practice pre.code-block {direction:ltr;text-align:left;max-width:100%;overflow-x:auto;overscroll-behavior-inline:contain;white-space:pre;color:#f8fff9;background:#103d30;border:1px solid #28684a;unicode-bidi:isolate}
#examples pre.code-block code,#practice pre.code-block code {color:inherit;white-space:inherit;overflow-wrap:normal;word-break:normal}
#idea,#examples,#practice,#questions {min-width:0;max-width:100%}
main.lesson-main {min-width:0} .source-note{font-size:.88rem;color:var(--muted)}
@media(max-width:720px){.lesson-main,.site-header,.toc{min-width:0} .code-block{font-size:.85rem;max-width:100%}}