@charset "UTF-8";
:root{--paper:#f7f6f0;--ink:#292d27;--muted:#63695f;--moss:#425d3a;--soft:#e8ecdf;--line:#d6d9cd;--error:#8c342b;--error-bg:#f7e4de;font-family:Arial,"Helvetica Neue",sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none;line-height:1.6}
*{box-sizing:border-box}body{margin:0}a{color:inherit;text-underline-offset:5px}a:hover{color:var(--moss)}button,input,select,textarea{font:inherit}button,.file-label{cursor:pointer}button,select,.file-label{border:1px solid var(--line);background:transparent;color:var(--ink);padding:.65rem 1rem;border-radius:5px}button:hover,.file-label:hover{background:var(--soft);border-color:var(--moss)}button:disabled{opacity:.5;cursor:default}:focus-visible{outline:3px solid var(--moss);outline-offset:4px}input[type=radio]{accent-color:var(--moss);width:17px;height:17px;vertical-align:middle}textarea{resize:vertical;width:100%;color:var(--ink);background:#fcfcf8;border:1px solid #7b8772;border-radius:5px;padding:1.1rem;font-size:1.15rem;line-height:1.8;min-height:140px}textarea:focus{outline:2px solid var(--moss);outline-offset:3px}header,main,footer{max-width:1160px;margin:auto;padding-left:40px;padding-right:40px}header{display:flex;justify-content:space-between;align-items:center;gap:24px;min-height:114px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:12px;font-size:1.25rem;font-weight:700;text-decoration:none;white-space:nowrap}.brand-mark{background:var(--moss);color:var(--paper);font-family:Georgia,serif;padding:1px 8px 4px;border-radius:3px;font-size:1.6rem}.brand-note{display:none;font-size:.7rem;font-weight:400;color:var(--muted)}nav{display:flex;gap:26px;flex-wrap:wrap}nav a{text-decoration:none;font-size:.9rem}nav a[aria-current]{color:var(--moss);text-decoration:underline;text-decoration-thickness:2px}main{min-height:70vh}.intro{padding:64px 0 34px;position:relative}.eyebrow{font-size:.68rem;font-weight:700;letter-spacing:.16em;color:var(--moss);text-transform:uppercase}h1{font-family:Georgia,"Times New Roman",serif;line-height:1.13;font-size:clamp(2.7rem,5.5vw,4.8rem);font-weight:400;letter-spacing:-.045em;margin:20px 0 24px}h1 em{color:var(--moss);font-weight:400}.intro>p:last-child{max-width:440px;color:var(--muted);font-size:1rem}.intro:after{content:"ă â ê\A ô ơ ư";white-space:pre;position:absolute;right:32px;top:70px;color:var(--line);font-family:Georgia,serif;font-size:5.8rem;line-height:1.1;letter-spacing:.06em;transform:rotate(-7deg);pointer-events:none}#trainer{border-top:1px solid var(--line);padding:24px 0 0}.toolbar,.session-heading,.session-bottom{display:flex;align-items:center;justify-content:space-between;gap:20px}.toolbar{padding-bottom:25px;border-bottom:1px solid var(--line)}fieldset{margin:0;padding:0;border:0;display:flex;gap:20px}legend{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}fieldset label{font-size:.9rem;white-space:nowrap}.quiet{font-size:.85rem;padding:.4rem .7rem;border-color:transparent;color:var(--moss)}.session-heading{padding:26px 0 16px}h2{font-family:Georgia,"Times New Roman",serif;font-weight:400;font-size:1.55rem;line-height:1.35;margin:6px 0 12px}.clock{display:flex;gap:10px;align-items:baseline;white-space:nowrap}.clock span{font-size:2.4rem;font-variant-numeric:tabular-nums;letter-spacing:-.06em}.clock small{color:var(--muted);font-size:.75rem}.passage{font-family:Georgia,"Times New Roman",serif;font-size:clamp(1.3rem,2.3vw,1.7rem);line-height:1.9;letter-spacing:.015em;color:var(--muted);height:172px;overflow-y:auto;position:relative;margin-bottom:25px;scrollbar-width:thin;white-space:pre-wrap;overflow-wrap:anywhere}.passage span.correct{color:var(--moss)}.passage span.incorrect{color:var(--error);background:var(--error-bg);text-decoration:underline}.passage span.cursor{border-left:2px solid var(--moss);margin-left:-2px;background:var(--soft)}.input-label{font-size:.82rem;display:block;margin-bottom:9px;font-weight:700}.input-label span{font-weight:400;color:var(--muted)}.muted{font-size:.8rem;color:var(--muted)}.session-bottom{margin-top:22px}.metrics{display:flex;gap:30px;flex-wrap:wrap;font-size:.85rem;color:var(--muted)}.metrics strong{font-size:1.7rem;color:var(--ink);font-weight:400;font-variant-numeric:tabular-nums}.status{min-height:26px;font-size:.82rem;color:var(--moss);margin:18px 0}#result{border-top:2px solid var(--moss);background:var(--soft);padding:28px;margin:30px 0}#result-summary{font-size:1.5rem}#result a{margin-left:18px;font-size:.9rem}#share-fallback{margin-top:20px}.below{display:grid;grid-template-columns:1fr 1fr;gap:60px;padding:30px 0 55px;border-top:1px solid var(--line);margin-top:32px;font-size:.85rem;color:var(--muted)}.below b{color:var(--ink);font-weight:400;font-family:Georgia,serif;font-size:1.15rem}.page-head{padding:60px 0 36px;max-width:760px}.page-head h1{font-size:3.6rem}.page-head>p:not(.eyebrow){color:var(--muted)}.lesson-list{list-style:none;padding:0;margin:0 0 70px;display:grid;grid-template-columns:1fr 1fr;column-gap:42px}.lesson-list li{border-top:1px solid var(--line)}.lesson-list a{display:flex;gap:20px;align-items:baseline;padding:24px 0;text-decoration:none}.lesson-list a>span:nth-child(2){flex:1}.lesson-number{color:var(--moss);font-size:.8rem;font-variant-numeric:tabular-nums}.lesson-list small{font-size:.7rem;color:var(--muted)}.lesson-list h2{font-size:1.4rem}.lesson-list p{font-size:.8rem;color:var(--muted);margin:0}.prose{max-width:740px;padding:65px 0 90px}.prose h1{font-size:3.3rem;margin-bottom:35px}.prose h2{font-size:1.8rem;margin-top:35px}.prose p,.prose li{line-height:1.9}.prose li{margin:10px 0}.data-actions{display:flex;flex-wrap:wrap;gap:12px;margin:24px 0}.file-label{display:inline-block}input[type=file]{max-width:240px;font-size:.8rem}.table-wrap{overflow:auto;margin:30px 0 70px}table{width:100%;border-collapse:collapse;font-size:.85rem;white-space:nowrap;text-align:left}caption{text-align:left;color:var(--muted);padding:16px 0}th,td{border-bottom:1px solid var(--line);padding:15px 12px}th{font-weight:400;color:var(--moss)}footer{padding-top:32px;padding-bottom:40px;border-top:1px solid var(--line);display:flex;gap:24px;align-items:center;justify-content:space-between}footer p{font-size:.8rem;color:var(--muted)}footer nav{gap:20px}footer nav a{font-size:.75rem}.skip{position:fixed;top:-100px;left:15px;background:var(--paper);padding:12px;z-index:10}.skip:focus{top:10px}.notice{padding:20px;border:1px solid var(--moss)}[hidden]{display:none!important}
/* Giữ phần mở đầu gọn để ô luyện xuất hiện sớm, kể cả màn hình laptop thấp. */
header{min-height:86px}
.intro{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(0,1fr);column-gap:48px;padding:28px 0 22px}
.intro .eyebrow{grid-column:1/-1;margin:0}
.intro h1{font-size:clamp(2rem,3.4vw,3rem);margin:12px 0 0;letter-spacing:-.035em}
.intro>p:last-child{align-self:end;margin:12px 0 3px;max-width:340px;font-size:.92rem}
.intro:after{display:none}
.passage{height:140px}
button,a,select,.file-label{transition:color .15s ease,background-color .15s ease,border-color .15s ease}
@media(min-width:1200px){.brand-note{display:inline;margin-left:8px}}
@media(max-width:760px){.intro{display:block;padding:24px 0 18px}.intro h1{font-size:2.25rem}.intro>p:last-child{font-size:.85rem;max-width:100%}.intro .eyebrow{font-size:.65rem}}
@media(max-width:760px){header,main,footer{padding-left:22px;padding-right:22px}header{flex-wrap:wrap;padding-top:22px;padding-bottom:20px;gap:20px}header nav{width:100%;gap:25px}header nav a{font-size:.82rem}.intro{padding-top:36px}.intro:after{display:none}h1{font-size:3.4rem}.toolbar{align-items:flex-start;gap:16px;flex-wrap:wrap}fieldset{gap:16px}.session-heading{gap:12px}.session-heading h2{font-size:1.35rem}.clock{gap:5px}.clock span{font-size:2rem}.clock small{display:none}.input-label span{display:block;font-size:.75rem}.passage{height:185px;font-size:1.4rem}.metrics{gap:16px;font-size:.75rem}.metrics strong{font-size:1.4rem}.session-bottom{gap:10px}.session-bottom button{padding:.5rem .65rem;font-size:.8rem}.below{grid-template-columns:1fr;gap:6px;padding-bottom:28px}.lesson-list{grid-template-columns:1fr}.page-head h1,.prose h1{font-size:2.8rem}.page-head,.prose{padding-top:40px}footer{align-items:flex-start;flex-direction:column;gap:12px}footer p{margin:0}#result{padding:20px}#result a{display:block;margin:16px 0 0}#result-summary{font-size:1.2rem}}
.trainer-actions{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}
.trainer-actions button{min-height:44px}nav a{display:inline-flex;align-items:center;min-height:44px}
.search-controls{display:flex;align-items:end;gap:14px;flex-wrap:wrap;margin-top:24px}
.search-controls label{display:block;font-size:.85rem}
.search-controls input[type=search]{display:block;width:min(100%,400px);min-width:250px;margin-top:7px;border:1px solid var(--line);border-radius:5px;background:#fcfcf8;color:var(--ink);padding:.65rem .85rem}
.progress-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:24px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:18px 0;margin:26px 0}
.progress-stats p{margin:0}.progress-stats strong{display:block;font-size:2rem;font-weight:400;font-variant-numeric:tabular-nums}.progress-stats span{font-size:.8rem;color:var(--muted)}
.post-meta{font-size:.8rem;color:var(--muted);margin-bottom:28px}.blog-list{list-style:none;padding:0;margin:0 0 64px}.blog-list li{padding:25px 0;border-top:1px solid var(--line)}.blog-list h2{margin-top:8px}.blog-list h2 a{text-decoration:none}.blog-list p{max-width:720px;color:var(--muted)}
.prose .table-wrap{margin:25px 0}.prose table{white-space:normal}.prose th{font-weight:700}.prose td,.prose th{vertical-align:top}.prose code{font-family:Consolas,monospace;font-size:.9em;background:var(--soft);padding:2px 5px;border-radius:3px}.prose .notice{margin:28px 0}.related-posts{margin-top:40px;border-top:1px solid var(--line);padding-top:12px}
.prose nav[aria-label="Bài viết liên quan"]{display:block;margin-top:36px;border-top:1px solid var(--line);padding-top:15px}.prose nav a{min-height:44px}#blog-list time{font-size:.75rem;color:var(--muted)}
/* Font hệ thống giữ dấu tiếng Việt rõ, tránh fallback rời dấu ở tiêu đề serif. */
h1,h2,.prose h1,.prose h2{font-family:Arial,"Helvetica Neue",sans-serif;font-weight:500;letter-spacing:-.02em;line-height:1.25}h1 em{font-style:normal}.prose h1{font-size:clamp(2rem,4vw,2.8rem)}.prose h2{font-size:1.5rem}.passage{font-family:Arial,"Helvetica Neue",sans-serif;font-size:1.45rem;line-height:1.8}.below b{font-family:inherit;font-weight:600}
@media(max-width:760px){header{padding-top:16px;padding-bottom:12px;gap:8px}.intro{padding:18px 0 14px}.intro h1{font-size:1.9rem;line-height:1.2}.intro>p:last-child{font-size:.85rem}.passage{height:132px}.session-heading{padding:18px 0 10px}.toolbar{padding-bottom:16px}#trainer{padding-top:16px}}
body.focus-mode header,body.focus-mode footer,body.focus-mode .intro,body.focus-mode .below{display:none}body.focus-mode main{max-width:1000px;padding-top:24px}body.focus-mode #trainer{border-top:0}#focus-mode-toggle[aria-pressed=true]{border-color:var(--moss);background:var(--soft)}
@media(max-width:760px){header nav{gap:18px}.trainer-actions{justify-content:flex-start}.toolbar{gap:12px}.search-controls{align-items:stretch;gap:10px}.search-controls input[type=search]{min-width:0;width:100%}.search-controls label{width:100%}.progress-stats{gap:12px}.progress-stats strong{font-size:1.65rem}.progress-stats span{font-size:.7rem}.prose table{min-width:460px}.intro{padding-top:24px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;animation:none!important;transition:none!important}}

.breadcrumbs{display:block;padding-top:20px;color:var(--muted);font-size:.8rem}
.breadcrumbs ol{display:flex;flex-wrap:wrap;align-items:center;gap:0;list-style:none;margin:0;padding:0}
.breadcrumbs li{display:flex;align-items:center;min-width:0;overflow-wrap:anywhere}
.breadcrumbs li+li:before{content:"/";margin:0 10px;color:var(--muted)}
.breadcrumbs a{font-size:inherit;min-height:44px;text-decoration:underline}
.breadcrumbs [aria-current]{color:var(--ink)}
.support-block{border-top:1px solid var(--line);padding-top:32px;margin-top:12px}
.support-block h3{font-size:1.05rem;margin-top:28px;line-height:1.5}
.related-lessons{display:block;border-top:1px solid var(--line);margin-top:32px;padding-top:8px}
.related-lessons ul{padding-left:22px}.related-lessons a{font-size:inherit;text-decoration:underline}
body.focus-mode .support-block,body.focus-mode .breadcrumbs{display:none}