.course-shell{max-width:1320px;padding:56px 32px 100px;margin:auto}
.breadcrumb{margin-bottom:28px;color:var(--muted);font-size:11px;font-weight:600}
.breadcrumb a:hover{color:var(--primary)}
.breadcrumb span{margin:0 6px;color:var(--faint)}

.course-header{display:flex;flex-wrap:wrap;align-items:flex-start;justify-content:space-between;gap:20px 32px;padding:36px;background:var(--surface);border:1px solid var(--line);border-radius:16px}
.course-header .course-code{color:var(--primary);font:700 11px var(--font-mono);letter-spacing:.1em}
.course-header h1{margin:10px 0 6px;font-size:clamp(30px,4vw,42px);font-weight:800;letter-spacing:-.02em}
.course-header .course-en{color:var(--muted);font-size:13px}
.course-header-right{display:flex;flex-direction:column;align-items:flex-end;gap:14px;margin-left:auto}
.stat-row{display:flex;gap:10px;flex-wrap:wrap;justify-content:flex-end}
.stat-card{display:flex;align-items:center;gap:10px;min-width:112px;padding:14px 16px;background:var(--bg);border:1px solid var(--line);border-radius:12px;box-shadow:0 3px 10px -6px rgb(15 23 42 / .12);transition:.3s var(--ease)}
.stat-card:hover{transform:translateY(-3px);border-color:rgb(var(--primary-rgb) / .3);box-shadow:0 16px 28px -14px rgb(15 23 42 / .25)}
.stat-card .icon{flex-shrink:0;width:20px;height:20px;color:var(--primary)}
.stat-card strong{display:block;color:var(--ink);font-size:22px;letter-spacing:-.03em}
.stat-card span{color:var(--muted);font-size:10px;letter-spacing:.02em}

.mini-progress b{background:linear-gradient(90deg,var(--primary),#60a5fa)}

/* Horizontal course navigation - shared across overview + week pages */
.course-nav{position:sticky;top:76px;z-index:5;display:flex;gap:4px;overflow-x:auto;margin-top:8px;padding-bottom:0;background:var(--bg);border-bottom:1px solid var(--line)}
.course-nav a,.course-nav .nav-item{display:inline-flex;align-items:center;gap:6px;padding:14px 16px;white-space:nowrap;color:var(--muted);font-size:13px;font-weight:600;border-bottom:2px solid transparent}
.course-nav a:hover{color:var(--ink)}
.course-nav a.active{color:var(--primary);border-bottom-color:var(--primary)}
.course-nav .nav-item[aria-disabled="true"]{color:var(--faint);cursor:not-allowed}
.course-nav .nav-item svg{width:11px;height:11px;flex-shrink:0}
.course-nav .nav-item small{font-size:9px;font-weight:600;color:var(--faint)}

.course-main{display:flex;flex-direction:column;gap:20px}

.panel{padding:32px 36px;background:var(--surface);border:1px solid var(--line);border-radius:16px}
.panel+.panel{border-top:none}
.panel h2{margin-bottom:6px;font-size:21px;letter-spacing:-.01em}
.panel-lead{max-width:640px;color:var(--muted);font-size:14px;line-height:1.75}

.intro-panel{display:flex;gap:24px;align-items:flex-start;position:relative;overflow:hidden;padding:32px;border:1px solid var(--line);border-radius:16px;background:linear-gradient(135deg,var(--tint) 0%,var(--surface) 60%)}
.intro-panel::before{content:'';position:absolute;top:-70px;right:-70px;width:220px;height:220px;border-radius:50%;background:radial-gradient(circle,rgb(37 99 235 / .12),transparent 70%)}
.intro-panel-icon{position:relative;z-index:1;flex-shrink:0;display:grid;place-items:center;width:56px;height:56px;border-radius:14px;background:var(--primary);color:#fff;box-shadow:0 12px 24px -8px rgb(37 99 235 / .4)}
.intro-panel-icon svg{width:26px;height:26px}
.intro-panel-body{position:relative;z-index:1;flex:1;min-width:0}
.intro-panel .eyebrow{margin-bottom:10px}
.intro-panel h2{margin-bottom:4px}
.intro-subtitle{margin-bottom:14px;color:var(--muted);font-size:12px;font-weight:600;letter-spacing:.02em}
@media(max-width:600px){.intro-panel{flex-direction:column;padding:26px}}

.req-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:22px}
.req-card{padding:22px;background:var(--surface);border:1px solid var(--line);border-radius:12px;transition:.3s var(--ease)}
.req-card:hover{transform:translateY(-4px);border-color:rgb(var(--primary-rgb) / .35);box-shadow:0 0 0 1px rgb(var(--primary-rgb) / .1),0 20px 36px -18px rgb(15 23 42 / .22)}
.req-card h3{display:flex;align-items:center;gap:8px;font-size:14px;margin-bottom:12px}
.req-card h3 .icon{font-size:16px;color:var(--primary)}
.req-card p{margin:0;color:var(--muted);font-size:12px;line-height:1.7}
.req-card ul{margin:0;padding-left:18px;color:var(--muted);font-size:12px;line-height:1.8}
.req-card ul li+li{margin-top:4px}
.tool-list{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}
.tool-list span{padding:6px 12px;background:var(--tint);color:var(--primary-ink);border-radius:6px;font-size:11px;font-weight:600}
.req-note{margin-top:12px;color:var(--muted);font-size:11px}

.warning-box{margin-top:16px;padding:20px 22px;background:var(--warn-bg);border:1px solid var(--warn-border);border-left:3px solid var(--warn-accent);border-radius:12px}
.warning-box h3{display:flex;align-items:center;gap:8px;margin-bottom:8px;color:var(--warn-text-strong);font-size:14px}
.warning-box h3 .icon{font-size:16px}
.warning-box p{margin:0;color:var(--warn-text);font-size:12px;line-height:1.7}
.warning-box p+p{margin-top:8px}

.download-card{margin-top:16px;display:flex;align-items:center;gap:16px;padding:18px 20px;background:var(--tint);border:1px solid var(--line);border-radius:10px;transition:.3s var(--ease)}
.download-card:hover{transform:translateY(-3px);border-color:rgb(var(--primary-rgb) / .4);box-shadow:0 18px 32px -18px rgb(var(--primary-rgb) / .3)}
.download-card .icon{display:grid;place-items:center;flex-shrink:0;width:38px;height:38px;border-radius:8px;background:var(--primary);color:#fff}
.download-card .icon svg{width:18px;height:18px}
.download-card-body{flex:1;min-width:0}
.download-card-body strong{display:block;margin-bottom:2px;color:var(--ink);font-size:13px}
.download-card-body span{color:var(--muted);font-size:11px}
.download-card .dark-button{flex-shrink:0;padding:10px 16px;font-size:11px}
@media(max-width:600px){.download-card{flex-wrap:wrap}}

.qa-block{margin:22px 0;padding:22px 24px;background:var(--surface);border:1px solid var(--line);border-radius:12px}
.qa-block .eyebrow{margin-bottom:8px}
.qa-block h3{font-size:16px;margin-bottom:10px}
.qa-explain{display:grid;grid-template-columns:1fr 1fr;gap:12px 20px;margin:16px 0 0;padding:16px 18px;background:var(--tint);border-radius:10px}
.qa-explain-label{display:block;margin-bottom:5px;color:var(--primary-ink);font-size:10px;font-weight:800;letter-spacing:.08em}
.qa-explain p{margin:0;font-family:var(--font-sans);color:var(--body);font-size:13.5px;line-height:1.75}
@media(max-width:600px){.qa-explain{grid-template-columns:1fr}}

.answer-cta{position:relative;overflow:hidden;display:flex;align-items:center;gap:24px;margin-top:20px;padding:28px 32px;background:linear-gradient(135deg,var(--ink-solid) 0%,#1e293b 100%);border-radius:14px;color:#fff}
.answer-cta::before{content:'';position:absolute;top:-60px;right:-60px;width:200px;height:200px;border-radius:50%;background:radial-gradient(circle,rgb(37 99 235 / .35),transparent 70%)}
.answer-cta-icon{position:relative;z-index:1;flex-shrink:0;display:grid;place-items:center;width:52px;height:52px;border-radius:12px;background:rgb(255 255 255 / .12);color:#93c5fd}
.answer-cta-icon svg{width:24px;height:24px}
.answer-cta-body{position:relative;z-index:1;flex:1;min-width:0}
.answer-cta-body .eyebrow{color:#bfdbfe;margin-bottom:6px}
.answer-cta-body h3{display:block;margin:0 0 6px;font-size:18px;color:#fff}
.answer-cta-body h3::before{display:none}
.answer-cta-body p{margin:0;color:#ffffff;font-size:13.5px;font-weight:500;line-height:1.7;max-width:480px}
.answer-cta .primary-button{position:relative;z-index:1;flex-shrink:0;white-space:nowrap}
@media(max-width:680px){.answer-cta{flex-direction:column;align-items:flex-start}}

.official-badge{display:inline-flex;align-items:center;gap:6px;margin-bottom:16px;padding:6px 12px;border-radius:99px;background:var(--primary);color:#fff;font-size:10px;font-weight:800;letter-spacing:.05em}
.official-badge svg{width:13px;height:13px;flex-shrink:0}
.practice-lab.official-lab p{color:#e2e8f0;font-size:14px;line-height:1.8}
.practice-lab.official-lab p strong{color:#93c5fd}
.practice-lab.official-lab p+p{margin-top:12px}
.extra-divider{display:flex;align-items:center;gap:12px;margin:40px 0 6px;color:var(--muted);font-size:10px;font-weight:800;letter-spacing:.1em}
.extra-divider::before,.extra-divider::after{content:'';flex:1;height:1px;background:var(--line)}
.extra-intro{margin-bottom:18px;color:var(--muted);font-size:12px;line-height:1.7}

.score-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:22px}
.score-card{padding:22px;background:var(--surface);border:1px solid var(--line);border-radius:12px;transition:.3s var(--ease)}
.score-card:hover{transform:translateY(-4px);border-color:rgb(var(--primary-rgb) / .35);box-shadow:0 0 0 1px rgb(var(--primary-rgb) / .1),0 20px 36px -18px rgb(15 23 42 / .22)}
.score-card strong{display:block;color:var(--primary);font-size:32px;font-weight:800;letter-spacing:-.03em}
.score-card span{color:var(--muted);font-size:11px;line-height:1.5}

.roadmap{margin-top:34px}
.roadmap-track{display:flex;position:relative;padding:0 4px}
.roadmap-track:before{content:'';position:absolute;top:28px;left:56px;right:56px;height:2px;background:linear-gradient(90deg,transparent,var(--line) 12%,var(--line) 88%,transparent);z-index:0}
.roadmap-step{flex:1;min-width:0;position:relative;z-index:1;display:flex;flex-direction:column;align-items:center;gap:6px;padding:0 6px;text-align:center;text-decoration:none;color:inherit}
.roadmap-node{display:grid;place-items:center;width:56px;height:56px;border-radius:50%;background:var(--tint);border:2px solid var(--primary);color:var(--primary-ink);font:700 16px var(--font-mono);margin-bottom:8px;box-shadow:0 10px 20px -10px rgb(37 99 235 / .35);transition:.3s var(--ease)}
.roadmap-step:hover .roadmap-node{transform:translateY(-3px) scale(1.06);box-shadow:0 16px 28px -12px rgb(var(--primary-rgb) / .45)}
.roadmap-label{color:var(--muted);font:700 11px var(--font-mono);letter-spacing:.1em}
.roadmap-title{font-size:13px;font-weight:600;color:var(--ink);line-height:1.4;max-width:150px}
.roadmap-topics{font-size:10px;color:var(--muted);line-height:1.5;max-width:150px}

.week-status{display:inline-flex;padding:6px 11px;border-radius:99px;background:var(--line);color:var(--muted);font-size:10px;font-weight:700}
.week-status.current{background:var(--tint);color:var(--primary-ink)}
.week-status.done{background:var(--tint);color:var(--primary-ink)}

.week-header{position:relative;overflow:hidden;display:flex;align-items:center;gap:28px;margin-top:8px;padding:32px 36px;background:linear-gradient(135deg,var(--tint) 0%,var(--surface) 65%);border:1px solid var(--line);border-left:4px solid var(--primary);border-radius:14px}
.week-header::before{content:'';position:absolute;top:-70px;right:-70px;width:220px;height:220px;border-radius:50%;background:radial-gradient(circle,rgb(37 99 235 / .12),transparent 70%)}
.week-header-content{flex:1;min-width:0;position:relative;z-index:1}
.week-header .week-tag{display:inline-flex;align-items:center;gap:7px;color:var(--primary);font:700 12px var(--font-mono);letter-spacing:.1em}
.week-header h1{display:table;margin:10px 0 8px -12px;padding:2px 12px;background:var(--tint);border-radius:8px;font-size:clamp(28px,4vw,40px)}
.week-header .week-meta{display:flex;flex-wrap:wrap;gap:14px;margin-top:2px;color:var(--muted);font-size:13px}
.week-header .week-meta span{padding:4px 11px;background:var(--surface);border:1px solid var(--line);border-radius:99px;font-weight:700;font-size:11px;color:var(--ink)}

/* Decorative "floating data card" illustration on the right side of
   the week header - purely ornamental, same motif reused on every
   week across every course (not tied to a specific week's content). */
.week-header-illustration{position:relative;z-index:1;flex-shrink:0;width:130px;height:110px;display:none}
@media(min-width:860px){.week-header-illustration{display:block}}
.whi-card{position:absolute;border-radius:12px;background:var(--surface);border:1px solid var(--line);box-shadow:0 16px 30px -16px rgb(15 23 42 / .25)}
.whi-card-back{top:18px;left:22px;width:92px;height:78px;opacity:.55;transform:rotate(-6deg)}
.whi-card-front{top:2px;left:6px;width:104px;height:90px;padding:12px;transform:rotate(3deg)}
.whi-table{display:flex;flex-direction:column;gap:6px}
.whi-row{display:flex;gap:4px}
.whi-row span{flex:1;height:7px;border-radius:2px;background:var(--tint)}
.whi-row-head span{background:var(--primary)}
.whi-badge{position:absolute;bottom:-10px;right:-12px;width:34px;height:34px;border-radius:50%;background:linear-gradient(135deg,var(--primary),#1d4ed8);display:grid;place-items:center;box-shadow:0 10px 20px -6px rgb(37 99 235 / .55);z-index:2}
.whi-badge svg{width:16px;height:16px;color:#fff}

@media(max-width:600px){.week-header{padding:26px 22px}}

/* 3-column lesson layout: TOC | content | learning panel */
.lesson-layout{display:grid;grid-template-columns:190px minmax(0,760px) 220px;gap:40px;align-items:start;padding-top:8px}
.lesson-toc{position:sticky;top:128px;display:flex;flex-direction:column;gap:2px}
.lesson-toc .side-label{margin-bottom:10px;color:var(--muted);font-size:10px;font-weight:800;letter-spacing:.14em}
.lesson-toc a{display:flex;gap:8px;padding:7px 8px;border-left:3px solid transparent;border-radius:0 6px 6px 0;color:var(--muted);font-size:12px;font-weight:600;transition:background .2s,color .2s,border-color .2s,transform .2s}
.lesson-toc a b{color:var(--faint);font:700 10px var(--font-mono)}
.lesson-toc a:hover{background:var(--tint);color:var(--ink)}
.lesson-toc a.active{background:var(--primary);border-left-color:var(--primary-ink);color:#fff;font-weight:800;box-shadow:0 4px 12px -4px rgb(37 99 235 / .5)}
.lesson-toc a.active b{color:#fff}

/* Nested sub-TOC: auto-built from each section's H3 headings (see
   course.js), collapsed by default and opened under whichever
   top-level link is currently active. Underlined rather than filled
   blue on its own active item, so it stays visually one step below
   the solid-fill H2-level active state above it. */
.toc-sub{list-style:none;margin:0 0 2px;padding:0;max-height:0;overflow:hidden;transition:max-height .3s ease}
.toc-sub.is-open{max-height:600px}
.toc-sub li{margin:0}
.toc-sub a{display:block;padding:6px 8px 6px 26px;color:var(--faint);font-size:11.5px;font-weight:600;line-height:1.4;border-left:3px solid transparent;transition:background .2s,color .2s}
.toc-sub a:hover{background:var(--tint);color:var(--ink)}
.toc-sub a.active{background:none;box-shadow:none;border-left-color:transparent;color:var(--ink);font-weight:700;text-decoration:underline;text-underline-offset:3px}
@media(max-width:1000px){.toc-sub{display:none}}

.lesson-content{min-width:0}
.lesson-section{padding:44px 0;border-top:1px solid var(--line)}
.lesson-section:first-child{padding-top:0;border-top:0}
.lesson-section h2{font-size:28px;margin-bottom:16px;scroll-margin-top:96px}
.lesson-section h3{display:flex;align-items:center;gap:9px;font-size:17px;letter-spacing:-.005em;color:var(--primary-ink);margin:0 0 10px;padding-top:26px;border-top:1px solid var(--line);scroll-margin-top:96px}
.lesson-section h3::before{content:'';width:6px;height:6px;border-radius:50%;background:var(--primary);flex-shrink:0}
.lesson-section h3:first-of-type{padding-top:0;border-top:0}
.lesson-section h4{margin:20px 0 8px;color:var(--primary);font-size:11px;font-weight:800;letter-spacing:.07em;text-transform:uppercase;scroll-margin-top:96px}
.lesson-section p{color:var(--body);font-size:14px;line-height:1.8;margin-bottom:14px}
.lesson-section ul{margin:0 0 14px;padding-left:20px;color:var(--body);font-size:14px;line-height:1.8}
.lesson-section li+li{margin-top:2px}

.definition{margin:16px 0;padding:16px 20px;background:var(--tint);border-left:3px solid var(--primary);border-radius:0 8px 8px 0;color:var(--ink);font-size:14px;line-height:1.8}

.ascii-block{margin:14px 0;padding:14px 16px;background:transparent;border:1px dashed var(--line);border-radius:8px;overflow-x:auto;font:12px/1.6 var(--font-mono);color:var(--muted);white-space:pre}

.inline-warning{margin:14px 0;padding:12px 16px;background:var(--warn-bg);border-left:3px solid var(--warn-accent);border-radius:6px;color:var(--warn-text);font-size:13px;line-height:1.7}
.inline-warning .icon{color:var(--warn-accent)}
.inline-ok{margin:14px 0;padding:12px 16px;background:var(--ok-bg);border-left:3px solid var(--ok-accent);border-radius:6px;color:var(--ok-text);font-size:13px;line-height:1.7}
.inline-danger{margin:14px 0;padding:12px 16px;background:var(--danger-bg);border-left:3px solid var(--danger-accent);border-radius:6px;color:var(--danger-text);font-size:13px;line-height:1.7}
.inline-danger .icon{color:var(--danger-accent)}

.table-wrap{overflow-x:auto;margin:16px 0}
.ref-table{width:100%;border-collapse:collapse;font-size:13px}
.ref-table th,.ref-table td{padding:10px 12px;border-bottom:1px solid var(--line);text-align:left}
.ref-table th{color:var(--muted);font-size:10px;font-weight:700;letter-spacing:.06em;text-transform:uppercase}
.ref-table code{white-space:nowrap}
.ref-table .table-tag{margin-left:8px;color:var(--muted);font-weight:600;text-transform:none;letter-spacing:0}
.ascii-label{margin:20px 0 0;color:var(--muted);font:12px var(--font-mono)}
.ascii-label+.table-wrap{margin-top:8px}

/* Byte-size comparison chart (e.g. TINYINT vs BIGINT): horizontal
   bars scaled to a value, so a size difference is felt, not just
   read off a table. */
.size-chart{margin:16px 0;padding:20px 22px;background:var(--surface);border:1px solid var(--line);border-radius:12px;display:flex;flex-direction:column;gap:12px}
.size-chart-row{display:grid;grid-template-columns:100px 1fr 56px;align-items:center;gap:12px}
.size-chart-track{height:10px;border-radius:99px;background:var(--tint);overflow:hidden}
.size-chart-bar{display:block;height:100%;border-radius:99px;background:linear-gradient(90deg,var(--primary),#60a5fa)}
.size-chart-value{font-size:11px;color:var(--muted);text-align:right;font-weight:700}
.er-relation{margin:10px 0 20px;color:var(--muted);font-size:12px;font-style:italic}
.er-side-by-side{display:flex;flex-wrap:wrap;gap:20px;margin:16px 0}
.er-side-by-side .table-wrap{flex:1;min-width:180px;margin:0}

.question-list{list-style:none;counter-reset:q;margin:20px 0;padding:0;border:1px solid var(--line);border-radius:12px;overflow:hidden}
.question-list li{counter-increment:q;position:relative;padding:14px 18px 14px 54px;color:var(--body);font-size:13.5px;line-height:1.75;transition:background .15s}
.question-list li:hover{background:var(--tint)}
.question-list li+li{border-top:1px solid var(--line)}
.question-list li::before{content:counter(q);position:absolute;left:16px;top:50%;transform:translateY(-50%);display:inline-flex;align-items:center;justify-content:center;width:24px;height:24px;border-radius:50%;background:var(--tint);color:var(--primary-ink);font:800 11px var(--font-mono)}

.qa-block .code-block pre,.qa-block .code-block code{user-select:none;-webkit-user-select:none;-moz-user-select:none}

.copy-guard{position:fixed;inset:0;z-index:90;display:flex;align-items:center;justify-content:center;padding:20px;background:rgb(15 23 42 / 0);pointer-events:none;transition:background .3s}
.copy-guard.show{background:rgb(15 23 42 / .5);pointer-events:auto}
.copy-guard-card{width:100%;max-width:340px;padding:28px 26px;background:var(--ink-solid);color:#fff;border-radius:16px;text-align:center;box-shadow:0 30px 60px -20px rgb(0 0 0 / .55);transform:scale(.6);opacity:0;transition:transform .4s cubic-bezier(.34,1.56,.64,1),opacity .25s}
.copy-guard.show .copy-guard-card{transform:scale(1);opacity:1}
.copy-guard-icon{display:grid;place-items:center;width:44px;height:44px;margin:0 auto 14px;border-radius:50%;background:rgb(255 255 255 / .12);color:#fbbf24}
.copy-guard-icon svg{width:22px;height:22px}
.copy-guard-card p{margin:0;font-size:14.5px;font-weight:700;line-height:1.6}

.schema-def{margin-bottom:18px}
.schema-def-head{margin:0;font-family:var(--font-mono);font-size:14px;font-weight:800;color:var(--ink)}
.schema-def-head u{text-decoration-color:var(--primary);text-decoration-thickness:2px}
.schema-def-body{margin:6px 0 0 28px;color:var(--body);font-size:13px;line-height:1.75}
.schema-def-body em{color:var(--muted);font-style:italic;font-weight:700;margin-right:2px}

.er-diagram{margin:20px 0;padding:24px;background:var(--surface);border:1px solid var(--line);border-radius:12px}
.er-diagram svg{width:100%;height:auto;max-width:420px;display:block;margin:0 auto}

/* Venn-diagram cheat-sheet grid (JOIN types, set operations, ...):
   small labelled cards, each holding one two-circle diagram. */
.venn-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(120px,1fr));gap:14px;margin:16px 0 20px}
.venn-card{display:flex;flex-direction:column;align-items:center;gap:8px;padding:14px 10px;background:var(--surface);border:1px solid var(--line);border-radius:10px;transition:.3s var(--ease)}
.venn-card:hover{transform:translateY(-3px);border-color:rgb(var(--primary-rgb) / .35);box-shadow:0 16px 28px -16px rgb(var(--primary-rgb) / .35)}
.venn-card svg{width:100%;max-width:110px;height:auto}
.venn-card .venn-label{font:700 10.5px var(--font-mono);color:var(--ink);letter-spacing:.02em;text-align:center}

/* Division-matrix (SQL "phép chia"): a rows-x-columns grid of yes/no
   marks, with the passing row highlighted - makes "has ALL of these"
   visible at a glance instead of reading a text checklist. */
.division-matrix{margin:16px 0;overflow-x:auto}
.division-table{border-collapse:separate;border-spacing:0;font-size:13px}
.division-table th,.division-table td{padding:10px 16px;text-align:center;border:1px solid var(--line)}
.division-table th{background:var(--bg);color:var(--muted);font:700 11px var(--font-mono);white-space:nowrap}
.division-table td.yes{color:var(--ok-accent);font-weight:800;background:var(--ok-bg)}
.division-table td.no{color:var(--danger-accent);font-weight:800;background:var(--danger-bg)}
.division-table td.verdict{font:700 11px var(--font-mono);white-space:nowrap}
.division-table td.verdict.pass{color:var(--ok-text)}
.division-table td.verdict.fail{color:var(--muted)}
.division-table tr.is-pass th:first-child{background:var(--primary);color:#fff}

/* Tier ladder (CASE WHEN classification, e.g. VIP/Thân thiết/Thường):
   stacked bands, darkest/strongest condition on top, so "check order
   = ladder order" is felt rather than read as a bullet list. */
.tier-ladder{margin:16px 0;border-radius:10px;overflow:hidden;border:1px solid var(--line)}
.tier-row{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:14px 18px}
.tier-row .tier-name{font:800 13px var(--font-sans);color:#fff}
.tier-row .tier-cond{font:600 12px var(--font-mono);color:rgb(255 255 255 / .85);text-align:right}
.tier-row.is-tier1{background:var(--primary)}
.tier-row.is-tier2{background:#60a5fa}
.tier-row.is-tier3{background:#64748b}

/* Character-strip highlight (LEFT()/RIGHT() and similar string
   functions): shows exactly which characters a function picks out of
   the source string. */
.char-strip{display:flex;align-items:center;gap:12px;margin:14px 0;flex-wrap:wrap}
.char-strip-label{font:700 11px var(--font-mono);color:var(--muted);min-width:130px}
.char-strip-chars{display:flex;gap:2px}
.char-strip-chars .ch{display:inline-flex;align-items:center;justify-content:center;width:24px;height:28px;border-radius:4px;background:var(--tint);color:var(--muted);font:700 13px var(--font-mono);transition:.2s}
.char-strip-chars .ch.is-picked{background:var(--primary);color:#fff}
.char-strip-result{font:700 12px var(--font-mono);color:var(--primary-ink)}

.checklist-progress{margin:16px 0 20px}
.checklist-progress-bar{height:8px;border-radius:99px;background:var(--line);overflow:hidden;margin-bottom:8px}
.checklist-progress-bar b{display:block;height:100%;border-radius:99px;background:linear-gradient(90deg,var(--primary),#60a5fa);width:0%;transition:width .3s}
.checklist-progress-label{color:var(--muted);font-size:11px;font-weight:700;letter-spacing:.03em}

.lesson-checklist{display:grid;grid-template-columns:1fr 1fr;gap:8px 20px;margin:0;padding:0;list-style:none}
.lesson-checklist li{display:flex;gap:10px;color:var(--body);font-size:13px;line-height:1.5;cursor:pointer;user-select:none;border-radius:4px;transition:color .15s}
.lesson-checklist li:before{content:'☐';flex-shrink:0;color:var(--primary)}
.lesson-checklist li:hover{color:var(--ink)}
.lesson-checklist li:focus-visible{outline:2px solid var(--primary);outline-offset:3px}
.lesson-checklist li.is-checked{color:var(--faint);text-decoration:line-through}
.lesson-checklist li.is-checked:before{content:'☑';color:var(--ok-accent)}

.flow-diagram{display:flex;flex-direction:column;align-items:center;gap:6px;margin:22px 0;padding:32px 20px;background:var(--surface);border:1px solid var(--line)}
.flow-diagram .flow-box{display:inline-flex;align-items:center;gap:8px;padding:12px 26px;background:var(--tint);color:var(--primary-ink);border-radius:8px;font-size:12px;font-weight:700;letter-spacing:.02em;transition:.3s var(--ease)}
.flow-diagram .flow-box svg{width:15px;height:15px;flex-shrink:0}
.flow-diagram .flow-box:hover{transform:translateY(-3px) scale(1.03);box-shadow:0 14px 26px -10px rgb(var(--primary-rgb) / .45);background:var(--primary);color:#fff}
.flow-diagram .flow-arrow{color:var(--faint);font-size:18px}
.flow-diagram .flow-arrow.has-label{color:var(--muted);font-size:12px;font-weight:600}

.example-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:20px 0}
.example-card{padding:18px 16px;background:var(--surface);border:1px solid var(--line);text-align:center;transition:.3s var(--ease)}
.example-card:hover{transform:translateY(-4px);border-color:rgb(var(--primary-rgb) / .35);box-shadow:0 0 0 1px rgb(var(--primary-rgb) / .1),0 18px 32px -18px rgb(15 23 42 / .22)}
.example-card .icon{font-size:24px;color:var(--primary)}
.example-card strong{display:block;margin:10px 0 4px;font-size:13px}
.example-card span{color:var(--muted);font-size:10px;line-height:1.5}

.code-block{position:relative;margin:20px 0;background:var(--ink-solid);border-radius:10px;overflow:hidden}
.code-block pre{margin:0;padding:22px 20px;overflow-x:auto;color:#e2e8f0;font:14px/1.6 var(--font-mono)}
.code-block .copy-btn{position:absolute;top:12px;right:12px;padding:6px 12px;background:#ffffff14;color:#e2e8f0;border:1px solid #ffffff26;border-radius:6px;font-size:10px;font-weight:700;cursor:pointer}
.code-block .copy-btn:hover{background:#ffffff26}
.code-block .copy-btn.copied{background:var(--primary);color:#fff;border-color:var(--primary)}

.quick-check{margin:26px 0;padding:22px 24px;background:var(--surface);border:1px solid var(--line);border-radius:10px}
.quick-check .eyebrow{margin-bottom:10px}
.quick-check .qc-question{margin-bottom:14px;font-size:14px;font-weight:600}
.quick-check .qc-options{display:flex;flex-direction:column;gap:8px}
.quick-check .qc-option{display:flex;align-items:center;gap:10px;padding:10px 14px;background:var(--bg);border:1px solid var(--line);border-radius:8px;color:var(--ink);font-size:13px;cursor:pointer;text-align:left;transition:background .15s,border-color .15s}
.quick-check .qc-option:hover{background:var(--tint);border-color:var(--primary)}
.quick-check .qc-option:disabled{cursor:default}
.quick-check .qc-option:disabled:not(.correct):not(.wrong){opacity:.55}
.quick-check .qc-option.correct{background:var(--ok-bg);border-color:var(--ok-border);color:var(--ok-text)}
.quick-check .qc-option.correct::after{content:'✓';margin-left:auto;color:var(--ok-accent);font-weight:800}
.quick-check .qc-option.wrong{background:var(--danger-bg);border-color:var(--danger-border);color:var(--danger-text-strong)}
.quick-check .qc-option.wrong::after{content:'✗';margin-left:auto;color:var(--danger-accent);font-weight:800}
@media (prefers-reduced-motion:no-preference){
  .quick-check .qc-option.is-shaking{animation:qc-shake .4s}
}
@keyframes qc-shake{
  10%,90%{transform:translateX(-1px)}
  20%,80%{transform:translateX(2px)}
  30%,50%,70%{transform:translateX(-4px)}
  40%,60%{transform:translateX(4px)}
}
.quick-check .qc-feedback{margin-top:14px;padding:12px 14px;border-radius:8px;font-size:12px;line-height:1.6;display:none}
.quick-check .qc-feedback.show{display:block}
.quick-check .qc-feedback.wrong{background:var(--danger-bg);color:var(--danger-text-strong)}
.quick-check .qc-feedback.correct{background:var(--ok-bg);color:var(--ok-text)}

/* Constraint/category picker: clickable pills that jump to and
   briefly flash the matching subsection below (see course.js),
   instead of a flat static list. */
.constraint-picker{display:flex;flex-wrap:wrap;gap:8px;margin:16px 0 20px}
.constraint-pill{padding:9px 16px;border-radius:99px;border:1px solid var(--line);background:var(--surface);color:var(--ink);font:700 12px var(--font-mono);letter-spacing:.02em;cursor:pointer;transition:.2s}
.constraint-pill:hover{border-color:var(--primary);color:var(--primary-ink);background:var(--tint);transform:translateY(-1px)}
.lesson-section h3.is-jumped{animation:courseJumpFlash 1.4s ease}
@keyframes courseJumpFlash{0%{background:var(--tint)}80%{background:var(--tint)}100%{background:transparent}}

.practice-lab{margin:32px 0;padding:32px;background:var(--ink-solid);border-radius:12px;color:#e2e8f0}
.practice-lab .eyebrow{display:flex;align-items:center;gap:8px;color:#93c5fd}
.practice-lab h3{display:block;color:#fff;font-size:20px;margin-bottom:14px}
.practice-lab h3::before{display:none}
.practice-lab ol{margin:0 0 22px;padding-left:20px;display:flex;flex-direction:column;gap:8px;font-size:13px;color:#cbd5e1}
.practice-lab strong{color:var(--accent-soft)}
.practice-lab .primary-button{background:#fff;color:var(--ink-solid)}
.practice-lab .primary-button:hover{background:#e2e8f0}

.challenge-list{display:flex;flex-direction:column;gap:14px;margin:20px 0}
.challenge-card{padding:20px 22px;background:var(--surface);border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:8px;transition:.3s var(--ease)}
.challenge-card:hover{transform:translateX(3px);box-shadow:0 14px 28px -18px rgb(15 23 42 / .25)}
.challenge-card-head{display:flex;align-items:center;gap:12px;margin-bottom:8px}
.challenge-num{display:grid;place-items:center;flex-shrink:0;width:26px;height:26px;border-radius:50%;background:var(--tint);color:var(--primary-ink);font:800 11px var(--font-mono)}
.challenge-card h4{margin:0;font-size:15px;color:var(--ink)}
.challenge-stars{margin-left:auto;flex-shrink:0;color:#f59e0b;font-size:13px;letter-spacing:1px}
.challenge-card>p{margin:0;color:var(--ink);font-size:13px;line-height:1.7}
.challenge-card details{margin-top:12px}
.challenge-card summary{list-style:none;display:inline-flex;align-items:center;gap:6px;cursor:pointer;color:var(--primary);font-size:12px;font-weight:700}
.challenge-card summary::-webkit-details-marker{display:none}
.challenge-card summary::before{content:'▸';display:inline-block;font-size:9px;transition:transform .15s}
.challenge-card details[open] summary::before{transform:rotate(90deg)}
.challenge-card details .ascii-block{margin:10px 0 0}
.challenge-card details[open] summary{margin-bottom:2px}

.learning-panel{position:sticky;top:128px;display:flex;flex-direction:column;gap:24px}
.panel-box{padding:20px;background:var(--surface);border:1px solid var(--line);border-radius:10px}
.panel-box .side-label{margin-bottom:12px;color:var(--muted);font-size:10px;font-weight:800;letter-spacing:.1em}
.panel-progress strong{font:700 22px var(--font-sans);color:var(--ink)}
.panel-progress strong span{color:var(--muted);font-size:13px;font-weight:600}
.checklist{margin:14px 0 0;padding:0;list-style:none;display:flex;flex-direction:column;gap:8px}
.checklist li{display:flex;align-items:center;gap:8px;color:var(--muted);font-size:12px}
.checklist li b{display:inline-flex;align-items:center;justify-content:center;width:14px;flex-shrink:0;color:var(--primary);font-size:12px}
.checklist li.done{color:var(--ink);font-weight:600}
.checklist li.current{color:var(--primary-ink);font-weight:800;background:var(--chip-blue-bg);margin:0 -8px;padding:4px 8px;border-radius:6px}
.checklist li.current b{width:16px;height:16px;border-radius:50%;background:var(--primary);color:#fff;font-size:10px}
.resource-list{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:10px}
.resource-list li{display:flex;align-items:center;gap:8px;color:var(--ink);font-size:12px;font-weight:600}
.resource-list .icon{color:var(--primary)}
.note-box{display:flex;gap:8px;color:var(--warn-text);background:var(--warn-bg);border:1px solid var(--warn-border);font-size:12px;line-height:1.6}
.note-box .icon{flex-shrink:0;margin-top:2px;color:var(--warn-accent)}
.note-box>span:last-child{min-width:0;overflow-wrap:break-word}

.color-legend-list{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:9px}
.color-legend-list li{display:flex;align-items:flex-start;gap:8px;color:var(--muted);font-size:11.5px;line-height:1.5}
.color-legend-dot{flex-shrink:0;width:9px;height:9px;margin-top:3px;border-radius:50%}
.color-legend-dot.is-blue{background:var(--primary)}
.color-legend-dot.is-green{background:var(--ok-accent)}
.color-legend-dot.is-yellow{background:var(--warn-accent)}
.color-legend-dot.is-red{background:var(--danger-accent)}
.color-legend-dot.is-black{background:var(--ink-solid)}

.color-legend-fab{position:fixed;left:22px;bottom:22px;z-index:70;width:46px;height:46px;border-radius:50%;background:var(--ink-solid);color:#fff;border:none;box-shadow:0 10px 24px -8px rgb(15 23 42 / .4);display:grid;place-items:center;cursor:pointer;transition:.15s}
.color-legend-fab:hover{background:var(--primary)}
.color-legend-fab svg{width:20px;height:20px}
.color-legend-fab[aria-expanded="true"]{background:var(--primary)}
.color-legend-popup{position:fixed;left:22px;bottom:78px;z-index:70;width:240px;padding:16px 18px;background:var(--surface);border:1px solid var(--line);border-radius:12px;box-shadow:0 18px 40px -12px rgb(15 23 42 / .3);animation:legend-pop-in .15s ease-out}
.color-legend-popup[hidden]{display:none}
.color-legend-popup-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px;color:var(--muted);font-size:10px;font-weight:800;letter-spacing:.1em}
.color-legend-close{padding:2px;background:none;border:none;color:var(--muted);font-size:14px;line-height:1;cursor:pointer}
.color-legend-close:hover{color:var(--ink)}
@keyframes legend-pop-in{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}
@media(max-width:760px){
  .color-legend-fab{left:16px;bottom:16px;width:42px;height:42px}
  .color-legend-popup{left:16px;right:16px;bottom:68px;width:auto}
}

.trigger-demo{margin:22px 0;padding:24px;background:var(--surface);border:1px solid var(--line);border-radius:10px}
.trigger-demo-actions{display:flex;gap:8px;margin:14px 0 20px}
.trigger-demo-actions button{padding:10px 18px;border:1px solid var(--line);border-radius:8px;background:var(--bg);color:var(--ink);font-size:12px;font-weight:700;cursor:pointer}
.trigger-demo-actions button.active{background:var(--primary);border-color:var(--primary);color:#fff}
.trigger-demo-tables{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.trigger-demo-table{padding:18px 14px;border:2px dashed var(--line);border-radius:8px;text-align:center;transition:.2s}
.trigger-demo-table.is-active{border-style:solid;border-color:var(--primary);background:var(--tint)}
.trigger-demo-table[data-table="inserted"].is-active{border-color:var(--ok-accent);background:var(--ok-bg)}
.trigger-demo-table[data-table="inserted"].is-active .trigger-demo-row{color:var(--ok-text)}
.trigger-demo-table[data-table="deleted"].is-active{border-color:var(--danger-accent);background:var(--danger-bg)}
.trigger-demo-table[data-table="deleted"].is-active .trigger-demo-row{color:var(--danger-text-strong)}
.trigger-demo-table .side-label{display:block;margin-bottom:10px}
.trigger-demo-row{min-height:20px;color:var(--muted);font:12px var(--font-mono)}
.trigger-demo-table.is-active .trigger-demo-row{color:var(--primary-ink);font-weight:700}
.trigger-demo-caption{margin-top:14px;color:var(--muted);font-size:11px;text-align:center}
.trigger-demo-sql{margin-top:16px;padding:16px 18px;background:var(--ink-solid);border-radius:8px}
.trigger-demo-sql .side-label{display:block;margin-bottom:8px;color:#93c5fd}
.trigger-demo-sql pre{margin:0;overflow-x:auto}
.trigger-demo-sql code{color:#e2e8f0;font:12px/1.6 var(--font-mono);white-space:pre}

.access-gate{margin:16px 0}
.access-locked{padding:36px 32px;text-align:center;background:var(--surface);border:1px dashed var(--line);border-radius:12px}
.access-locked-icon{display:grid;place-items:center;width:48px;height:48px;margin:0 auto 16px;border-radius:50%;background:var(--tint);color:var(--primary)}
.access-locked-icon svg{width:22px;height:22px}
.access-locked h3{margin-bottom:6px;font-size:16px}
.access-locked>p{max-width:360px;margin:0 auto 18px;color:var(--muted);font-size:13px;line-height:1.7}
.access-form{display:flex;gap:8px;max-width:360px;margin:0 auto}
.access-input{flex:1;padding:12px 14px;border:1px solid var(--line);border-radius:8px;background:var(--bg);color:var(--ink);font-size:13px;font-family:var(--font-mono);text-transform:uppercase;letter-spacing:.04em;transition:border-color .2s}
.access-input:focus-visible{outline:2px solid var(--primary);outline-offset:2px;border-color:var(--primary)}
.access-submit{white-space:nowrap}
.access-error{min-height:16px;margin:12px 0 0;color:var(--danger-accent);font-size:12px;font-weight:600}
.access-hint{margin:14px 0 0;color:var(--muted);font-size:11px}
.access-unlocked .access-success-msg{margin-bottom:16px}
.access-unlocked .access-logout{margin-top:14px}
@media(max-width:480px){.access-form{flex-direction:column}}

.week-nav-links{display:flex;align-items:stretch;justify-content:space-between;gap:16px;margin-top:44px}
.week-nav-links a,.week-nav-links .nav-disabled{flex:1;padding:18px 20px;background:var(--surface);border:1px solid var(--line);border-radius:10px;transition:.3s var(--ease)}
.week-nav-links a:hover{transform:translateY(-4px);border-color:rgb(var(--primary-rgb) / .35);box-shadow:0 0 0 1px rgb(var(--primary-rgb) / .1),0 20px 36px -18px rgb(15 23 42 / .22)}
.week-nav-links .nav-dir{display:block;margin-bottom:4px;color:var(--muted);font-size:10px;font-weight:700;letter-spacing:.06em}
.week-nav-links .nav-title{display:block;font-size:14px;font-weight:700;color:var(--ink)}
.week-nav-links .next{text-align:right}
.week-nav-links .nav-disabled{opacity:.5;cursor:not-allowed}

@media(max-width:760px){
  .course-nav{top:64px}
}
@media(max-width:1000px){
  .lesson-layout{grid-template-columns:1fr;gap:28px}
  .lesson-toc{position:static;flex-direction:row;overflow-x:auto;gap:4px}
  .lesson-toc .side-label{display:none}
  .lesson-toc a{white-space:nowrap}
  .learning-panel{position:static;flex-direction:row;overflow-x:auto}
  .panel-box{min-width:220px}
}
@media(max-width:900px){
  .score-grid,.req-grid{grid-template-columns:1fr 1fr}
  .example-grid{grid-template-columns:1fr 1fr}
  .roadmap-track{overflow-x:auto;padding-bottom:6px}
  .roadmap-step{min-width:130px}
  .roadmap-track:before{left:0;right:0}
}
@media(max-width:600px){
  .course-shell{padding:40px 20px 70px}
  .panel{padding:24px 22px}
  .course-header{flex-direction:column;align-items:flex-start;gap:20px}
  .course-header-right{align-items:flex-start}
  .stat-row{justify-content:flex-start}
  .score-grid,.example-grid,.req-grid,.lesson-checklist{grid-template-columns:1fr}
  .week-nav-links{flex-direction:column}
  .week-nav-links .next{text-align:left}
}