:root{--ink:#20252b;--text:#4c5560;--muted:#77808a;--line:#e7ebee;--soft:#f7f9fa;--blue:#235a7d;--blue2:#eff7fb;--gold:#d89d45;--green:#306b5d;--white:#fff;--shadow:0 16px 45px rgba(35,50,65,.10)}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#fff;color:var(--ink);font-family:"Segoe UI",Arial,sans-serif}a{text-decoration:none;color:inherit}.wrap{width:min(1240px,calc(100% - 40px));margin:auto}.topbar{height:108px;display:grid;grid-template-columns:320px minmax(0,1fr) 250px;align-items:center;gap:18px;border-bottom:1px solid #eef1f3;background:#fff;position:relative;z-index:100}.brand{display:flex;align-items:center;gap:11px;min-width:0}.brand-logo{width:75px;height:56px;border-radius:0;object-fit:contain;background:transparent;border:0}header .brand-logo{width:125px;height:93px}.footer .brand-logo{width:150px;height:112px}.brand-mark{width:48px;height:48px;border-radius:13px;display:grid;place-items:center;background:var(--blue2);font-size:25px;color:var(--blue)}.brand-copy b{display:block;font-size:15px;letter-spacing:.06em;color:#0d6fd8}.brand-copy small{display:block;color:var(--muted);font-size:10px;line-height:1.35;margin-top:3px;white-space:normal;overflow:visible;max-width:230px}.nav{display:flex;justify-content:center;align-items:center;gap:2px;min-width:0}.nav-item{position:relative}.nav-link{display:block;padding:12px 9px;font-size:13px;font-weight:700;color:#49545d;white-space:nowrap}.nav-link:hover{color:var(--blue)}.dropdown{position:absolute;top:42px;left:50%;transform:translate(-50%,8px);width:290px;padding:8px;background:#fff;border:1px solid var(--line);border-radius:13px;box-shadow:var(--shadow);opacity:0;visibility:hidden;transition:.18s}.nav-item:hover .dropdown{opacity:1;visibility:visible;transform:translate(-50%,0)}.drop-link{display:block;padding:10px;border-radius:9px}.drop-link:hover{background:var(--soft)}.drop-link b{display:block;font-size:12px}.drop-link small{display:block;margin-top:3px;color:var(--muted);font-size:10px;line-height:1.35}.auth{display:flex;justify-content:flex-end;gap:8px}.btn{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:39px;padding:9px 15px;border-radius:9px;border:1px solid var(--line);background:#fff;font-size:12px;font-weight:800;cursor:pointer}.btn.primary{background:var(--blue);color:#fff;border-color:var(--blue)}.btn.soft{background:var(--blue2);border-color:#d9eaf4;color:var(--blue)}.hero{position:relative;height:520px;overflow:hidden;background:#eaf1f5}.hero-slide{position:absolute;inset:0;opacity:0;transition:opacity .6s;background-position:center;background-size:cover}.hero-slide.active{opacity:1}.hero-slide:after{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(14,35,48,.82) 0%,rgba(14,35,48,.60) 42%,rgba(14,35,48,.16) 76%,rgba(14,35,48,.06) 100%)}.hero-slide.no-image{background:linear-gradient(120deg,#153f58,#4284a6)}.hero-content{position:relative;z-index:2;height:100%;display:flex;align-items:center}.hero-copy{max-width:620px;color:#fff}.eyebrow{font-size:11px;font-weight:900;letter-spacing:.15em;text-transform:uppercase;color:#ffd492}.hero h1{font-size:clamp(37px,5vw,64px);line-height:1.06;margin:14px 0 16px;letter-spacing:-.035em}.hero p{font-size:16px;line-height:1.7;color:#ecf2f5;max-width:570px}.hero-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:25px}.hero .btn{border-color:#ffffff66}.hero .btn:not(.primary){color:#fff;background:#ffffff12}.hero-dots{position:absolute;z-index:4;left:50%;bottom:20px;transform:translateX(-50%);display:flex;gap:7px}.hero-dot{width:8px;height:8px;border-radius:99px;border:0;background:#ffffff8f;cursor:pointer}.hero-dot.active{width:26px;background:#fff}.section{padding:40px 0}.section.soft{background:var(--soft)}.heading{text-align:center;max-width:760px;margin:0 auto 32px}.heading.left{text-align:left;margin-left:0}.heading h2{font-size:32px;margin:7px 0 10px;letter-spacing:-.02em}.heading p{margin:0;color:var(--text);line-height:1.65;font-size:14px}.subjects{display:grid;grid-template-columns:repeat(8,1fr);gap:16px;align-items:start}.subject{position:relative;text-align:center}.subject-main{display:flex;min-height:92px;flex-direction:column;align-items:center;justify-content:center;gap:0;background:#fff;border:1px solid var(--line);border-radius:18px;padding:12px;transition:.2s}.subject:hover .subject-main{transform:translateY(-3px);box-shadow:var(--shadow);border-color:#cbdfe9}.subject-icon{width:58px;height:58px;border-radius:50%;display:grid;place-items:center;background:var(--blue2);font-size:27px;overflow:hidden}.subject-icon img{width:100%;height:100%;object-fit:cover}.subject-main b{display:none}.subject-menu{position:absolute;z-index:20;left:50%;top:115px;width:230px;transform:translate(-50%,8px);background:#fff;border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);padding:7px;opacity:0;visibility:hidden;transition:.18s;text-align:left}.subject:hover .subject-menu{opacity:1;visibility:visible;transform:translate(-50%,0)}.subject-menu a{display:block;padding:9px;border-radius:8px;font-size:11px}.subject-menu a:hover{background:var(--soft)}.about{display:grid;grid-template-columns:minmax(0,.82fr) minmax(0,1.18fr);gap:28px;align-items:center;max-width:900px;margin:auto}.about-media{width:clamp(250px,32vw,390px);aspect-ratio:1/1;height:auto;max-width:100%;min-height:0;border-radius:50%;background:transparent;display:grid;place-items:center;overflow:hidden;justify-self:center}.about-media img{width:100%;height:100%;object-fit:cover;border-radius:50%;clip-path:circle(50% at 50% 50%);animation:tnmIntroDisc 36s linear infinite;transform-origin:50% 50%;will-change:transform;backface-visibility:hidden}@keyframes tnmIntroDisc{from{transform:rotate(0deg)}to{transform:rotate(360deg)}}.about-media .placeholder{font-size:84px}.about-copy h2{font-size:31px;margin:8px 0 14px}.about-copy p{color:var(--text);font-size:14px;line-height:1.65}.lessons{display:grid;grid-template-columns:repeat(4,1fr);gap:15px}.lesson-card{position:relative;background:#fff;border:1px solid var(--line);border-radius:16px;overflow:hidden;min-height:220px;transition:.2s}.lesson-card:hover{transform:translateY(-3px);box-shadow:var(--shadow)}.lesson-thumb{height:145px;background:linear-gradient(145deg,#e6f0f5,#c6dce6);display:grid;place-items:center;overflow:hidden}.lesson-thumb img{width:100%;height:100%;object-fit:cover}.lesson-thumb span{font-size:46px}.lesson-body{padding:13px 14px}.lesson-card h3{font-size:15px;line-height:1.35;margin:0 0 8px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}.lesson-foot{display:flex;align-items:center;justify-content:space-between;gap:10px}.lesson-subject{color:var(--muted);font-size:10px;font-weight:750}.lesson-go{width:30px;height:30px;border-radius:50%;display:grid;place-items:center;background:#eef5f8;color:var(--blue);font-weight:900}.lesson-go.locked{background:#f3f4f5;color:#818b92}.teachers-wrap{position:relative;overflow:hidden;touch-action:pan-y}.teachers-track{display:flex;gap:15px;width:max-content;padding:4px 2px 14px;will-change:transform;cursor:grab;user-select:none;-webkit-user-select:none;transform:translate3d(0,0,0)}.teachers-track.is-dragging{cursor:grabbing}.teachers-track img{-webkit-user-drag:none;user-drag:none}.teacher-card{flex:0 0 350px;background:#fff;border:1px solid var(--line);border-radius:14px;padding:10px}.teacher-card-inner{display:grid;grid-template-columns:92px 1fr;gap:12px;align-items:start}.teacher-id{text-align:center}.teacher-id .code{font-size:9px;color:var(--muted);font-weight:850;margin-top:5px;letter-spacing:.01em}.teacher-profile{font-size:10px;line-height:1.35;color:var(--text);padding:0;min-width:0;font-family:inherit}.teacher-profile-title{display:block;font-size:13px;font-weight:900;margin:-1px 0 5px;color:#263b49;line-height:1.15}.teacher-profile-meta{display:grid;gap:2px}.teacher-profile-meta div{font-size:10px;color:var(--text);overflow-wrap:anywhere;line-height:1.3;font-family:inherit}.teacher-profile-meta b{display:inline;font-weight:850;color:#33434d;margin:0}.teacher-address-row{padding-bottom:3px;border-bottom:1px solid var(--line)}.teacher-profile-bio{margin-top:4px!important;padding-top:2px;border-top:0;color:var(--text)!important;font-size:10px!important;line-height:1.35!important;font-family:inherit;display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden}.teacher-avatar-link{display:block}.teacher-avatar-link:focus-visible{outline:2px solid var(--blue);outline-offset:2px;border-radius:13px}.teacher-avatar{height:96px;border-radius:10px;background:linear-gradient(145deg,#e9eff2,#c5d6de);display:grid;place-items:center;overflow:hidden}.teacher-avatar img{width:100%;height:100%;object-fit:cover}.teacher-avatar span{font-size:38px}.teacher-card p{margin:0;color:var(--muted);font-size:10px;line-height:1.5}.teacher-nav{position:absolute;right:0;top:-56px;display:flex;gap:7px}.round{width:36px;height:36px;border-radius:50%;border:1px solid var(--line);background:#fff;font-size:17px;cursor:pointer}.feature-row{display:grid;grid-template-columns:1fr 1fr;min-height:330px;background:#fff;border:1px solid var(--line);border-radius:22px;overflow:hidden}.feature-row.reverse .feature-image{order:-1}.feature-copy{padding:45px;display:flex;flex-direction:column;justify-content:center}.feature-copy h2{font-size:31px;margin:7px 0 12px}.feature-copy p{color:var(--text);line-height:1.75;font-size:14px}.feature-image{background:linear-gradient(145deg,#d7e6ed,#9cc0d0);min-height:330px}.feature-image img{width:100%;height:100%;object-fit:cover}.mid-slider{height:330px;border-radius:22px;overflow:hidden;position:relative;background:#173d54}.mid-slide{position:absolute;inset:0;opacity:0;transition:.5s;background-position:center;background-size:cover}.mid-slide.active{opacity:1}.mid-slide:after{content:"";position:absolute;inset:0;background:linear-gradient(90deg,#173244cc,#17324435)}.mid-copy{position:relative;z-index:2;color:#fff;max-width:590px;padding:65px 55px}.mid-copy h2{font-size:36px;margin:8px 0 12px}.mid-copy p{line-height:1.7;color:#e9f0f3}.footer{background:#17232a;color:#eaf0f2;padding:34px 0 16px}.footer-grid{display:grid;grid-template-columns:1.5fr .7fr .7fr;gap:45px}.footer .brand-copy small,.footer p,.footer a{color:#9fb0b9}.footer h4{margin:2px 0 14px;font-size:13px}.footer-list{display:grid;gap:9px;font-size:11px}.footer-bottom{border-top:1px solid #ffffff18;margin-top:22px;padding-top:12px;color:#82949e;font-size:10px}.mobile-menu{display:none}.section-spaced{margin-top:12px}.lesson-search{max-width:520px;margin:0 0 20px}.lesson-search input{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:12px;font:inherit}.lessons.mode-list{display:block}.lessons.mode-list .lesson-card{display:grid;grid-template-columns:110px 1fr;min-height:100px;margin-bottom:9px}.lessons.mode-list .lesson-thumb{height:100%}.lessons.mode-icons .lesson-card{min-height:130px;text-align:center}.lessons.mode-icons .lesson-thumb{height:78px}.lesson-group{margin:24px 0}.lesson-group-title{font-size:17px;margin:0 0 10px}.lesson-group .lessons{margin-bottom:18px}.lesson-hidden{display:none!important}@media(max-width:1080px){.topbar{grid-template-columns:285px 1fr 210px}.nav-link{padding-left:6px;padding-right:6px;font-size:12px}.subjects{grid-template-columns:repeat(3,1fr)}.lessons{grid-template-columns:repeat(2,1fr)}.teachers-track{grid-auto-columns:calc((100% - 30px)/3)}}@media(max-width:780px){.wrap{width:min(100% - 26px,1240px)}.topbar{height:auto;min-height:96px;grid-template-columns:1fr auto;padding:8px 0}header .brand-logo{width:105px;height:78px}.footer .brand-logo{width:150px;height:112px}.nav{grid-column:1/-1;order:3;justify-content:flex-start;overflow:auto;border-top:1px solid #f0f2f4;padding-top:7px}.nav-item{flex:0 0 auto}.dropdown,.subject-menu{display:none}.auth .btn:not(.primary){display:none}.hero{height:465px}.subjects{grid-template-columns:repeat(2,1fr)}.about,.feature-row{grid-template-columns:1fr}.feature-row.reverse .feature-image{order:0}.feature-copy{padding:28px}.lessons{grid-template-columns:1fr 1fr}.teachers-track{grid-auto-columns:75%}.footer-grid{grid-template-columns:1fr 1fr}.footer-grid>div:first-child{grid-column:1/-1}}@media(max-width:520px){header .brand-logo{width:100px;height:75px}.footer .brand-logo{width:140px;height:105px}.brand-copy small{max-width:150px;white-space:normal}.auth .btn.primary{padding:9px 12px}.hero{height:450px}.hero h1{font-size:36px}.hero p{font-size:14px}.section{padding:34px 0}.heading h2,.about-copy h2{font-size:28px}.subjects,.lessons{grid-template-columns:1fr 1fr}.lesson-card{padding:13px;min-height:180px}.teacher-nav{display:none}.teachers-track{grid-auto-columns:84%}.feature-copy{padding:24px}.feature-copy h2{font-size:26px}.mid-copy{padding:44px 25px}.mid-copy h2{font-size:29px}.footer-grid{grid-template-columns:1fr}.footer-grid>div:first-child{grid-column:auto}}
/* V3-37 · Khám phá bài học: trái 6 avatar, phải = 2/3 cột trái */
#bai-hoc .lesson-discovery-layout{display:grid;grid-template-columns:minmax(0,3fr) minmax(300px,2fr);gap:22px;align-items:start}
#bai-hoc .lesson-discovery-cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
#bai-hoc .home-discovery-card{min-width:0}
#bai-hoc .lesson-discovery-side{border:1px solid var(--line);border-radius:16px;background:#fff;padding:13px;min-width:0}
#bai-hoc .lesson-discovery-side .lesson-search{max-width:none;margin:0 0 10px}
#bai-hoc .lesson-name-list{display:grid;gap:7px;max-height:515px;overflow:auto;padding-right:2px}
#bai-hoc .lesson-name-row{display:grid;grid-template-columns:25px minmax(0,1fr) 28px;gap:8px;align-items:center;padding:8px 9px;border:1px solid var(--line);border-radius:10px;background:#fff}
#bai-hoc .lesson-name-row.lesson-hidden{display:none!important}
#bai-hoc .lesson-name-dot{width:25px;height:25px;border-radius:50%;display:grid;place-items:center;background:var(--blue2);color:var(--blue);font-weight:900}
#bai-hoc .lesson-name-copy{min-width:0}.lesson-name-copy b{display:block;font-size:12px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.lesson-name-copy small{display:block;color:var(--muted);font-size:9.5px;margin-top:2px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
#bai-hoc .lesson-name-row>a,#bai-hoc .lesson-list-lock{width:28px;height:28px;border-radius:50%;display:grid;place-items:center;background:#eef5f8;color:var(--blue);font-size:18px;font-weight:900}
#bai-hoc .lesson-list-lock{background:#f3f4f5;color:#818b92;font-size:12px}
/* V3-38 · 3 trạng thái bài học Trang chủ: Xem thử / Khóa / Vào học */
#bai-hoc .home-state-icon{font-size:13px!important;line-height:1;display:grid;place-items:center}
#bai-hoc .home-state-icon.preview,#bai-hoc .home-list-state.preview{background:#eef6fb;color:#235a7d}
#bai-hoc .home-state-icon.learn,#bai-hoc .home-list-state.learn{background:#edf8f2;color:#237052}
#bai-hoc .home-list-state{font-size:12px!important;line-height:1}
@media(max-width:980px){#bai-hoc .lesson-discovery-layout{grid-template-columns:minmax(0,3fr) minmax(270px,2fr)}#bai-hoc .lesson-discovery-cards{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:780px){#bai-hoc .lesson-discovery-layout{grid-template-columns:1fr}#bai-hoc .lesson-discovery-cards{grid-template-columns:repeat(2,minmax(0,1fr))}#bai-hoc .lesson-discovery-side{order:2}#bai-hoc .lesson-name-list{max-height:330px}}
@media(max-width:520px){#bai-hoc .lesson-discovery-cards{gap:9px}#bai-hoc .home-discovery-card{min-height:175px;padding:0}#bai-hoc .home-discovery-card .lesson-thumb{height:108px}#bai-hoc .home-discovery-card .lesson-body{padding:10px}#bai-hoc .home-discovery-card h3{font-size:12px}}

 .home-custom-hero{min-height:350px;background-color:#173d36;background-size:cover}.home-custom-hero .hero-content{min-height:350px}.home-custom-hero .hero-copy{display:block}.home-custom-hero h1,.home-custom-hero p{color:white} .home-custom-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:20px}.home-custom-cards>a{padding:20px;border:1px solid #e3e8ec;border-radius:14px}.home-custom-cards img{max-width:100%;height:160px;object-fit:cover}