@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@400;500;600;700;800;900&display=swap');
:root{--ink:#141414;--muted:#686868;--line:#dededb;--paper:#fff;--soft:#f4f4f1;--max:1240px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:110px}body{margin:0;color:var(--ink);background:var(--paper);font-family:Pretendard,'Noto Sans KR',Arial,sans-serif;word-break:keep-all;line-height:1.75}a{color:inherit;text-underline-offset:4px}button,input,textarea,select{font:inherit}button,a,input,textarea{touch-action:manipulation}button{cursor:pointer;background:white;color:var(--ink);border:1px solid #aaa;padding:10px 16px}button:hover,.button:hover{background:#ebebe8}button:disabled{cursor:default;opacity:.55}a:focus-visible,button:focus-visible,input:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #3168b5;outline-offset:4px}.skip{position:absolute;top:-80px;left:15px;background:#000;color:#fff;padding:8px;z-index:99}.skip:focus{top:10px}.masthead{height:76px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 40px;gap:20px;background:white;position:sticky;top:0;z-index:20}.brand{font-size:16px;font-weight:800;text-decoration:none;letter-spacing:-.6px}.brand b{font-size:27px;margin-right:12px}.masthead nav{display:flex;gap:24px;font-size:13px}.masthead nav a{text-decoration:none}.eyebrow{font-size:11px;font-weight:700;letter-spacing:2px;text-transform:uppercase;color:var(--muted)}h1,h2,h3,h4{line-height:1.45;letter-spacing:-.055em;word-break:keep-all}h1{font-size:clamp(32px,4.3vw,58px);font-weight:800;margin:18px 0 25px;line-height:1.25}h2{font-size:28px;margin:12px 0 22px}h3{font-size:20px;margin:22px 0 12px}h4{font-size:17px}.muted{color:var(--muted)}.home{max-width:var(--max);padding:68px 40px;margin:auto}.intro{display:grid;grid-template-columns:1.6fr 1fr;gap:60px;align-items:end;padding-bottom:60px;border-bottom:1px solid var(--ink)}.intro 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0}.section-top{border-top:1px solid var(--ink);padding-top:22px}.objectives{padding:22px 25px;background:var(--soft)}.objectives ul{padding-left:20px;margin:10px 0}.objectives li{margin:5px 0;font-size:14px}.agenda{display:grid;grid-template-columns:repeat(4,1fr);border:1px solid var(--line);margin:25px 0}.agenda div{padding:15px;border-right:1px solid var(--line);font-size:12px}.agenda div:last-child{border:0}.agenda b{display:block;font-size:22px}.theory{margin:30px 0 45px}.theory p,.solution p{font-size:15px;line-height:1.95;margin:15px 0}.theory li,.solution li{font-size:14px;margin:8px 0}.table-scroll{overflow-x:auto;max-width:100%;margin:20px 0}table{border-collapse:collapse;width:100%;font-size:13px;margin:15px 0}td,th{padding:12px 14px;border:1px solid #d8d8d4;text-align:left;vertical-align:top}th{background:#f1f1ed;font-weight:600}.module-image{width:100%;display:block;max-height:380px;object-fit:cover;border:1px solid var(--line)}figure{margin:30px 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0;background:#f0f2ed;padding:15px;font-size:13px}.feedback.wrong{background:#fcf1ea}.grade-row{display:flex;align-items:center;gap:20px;margin:24px 0;flex-wrap:wrap}.grade-result{font-weight:700}.journal{width:100%;min-height:260px;resize:vertical;padding:18px;border:1px solid #bbb;background:#fff;font-size:14px;line-height:1.85}.save-note{font-size:11px;color:#666;min-height:22px}.assignment{padding:25px;border:1px solid var(--ink)}.assignment label{display:flex;align-items:flex-start;gap:10px;margin:20px 0;font-size:13px}.assignment input{accent-color:#000;margin-top:7px}.finish{padding:25px;background:#f3f3ef;margin:30px 0}.finish p{font-size:13px}.finish .status{font-weight:600;min-height:25px}.pager{display:flex;gap:20px;justify-content:space-between;border-top:1px solid var(--line);padding-top:25px;margin-top:45px}.pager a{font-size:13px}.resource-item{padding:20px 0;border-bottom:1px solid #ddd}.resource-item h4{margin:0 0 8px}.resource-item p{font-size:13px}.download{display:inline-block;margin:5px 5px 5px 0;font-size:12px;padding:6px 12px;border:1px solid #ccc;background:#fff}.source-note{color:#777;font-size:11px;line-height:1.8;margin-top:32px}.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:#171717;color:white;padding:12px 22px;font-size:13px;z-index:99;max-width:90vw}.empty{padding:80px 20px;text-align:center}code{font-family:ui-monospace,monospace;font-size:.9em;overflow-wrap:anywhere}pre{white-space:pre-wrap;overflow-wrap:anywhere}img{max-width:100%}[hidden]{display:none!important}
@media(min-width:1550px){.lesson{max-width:1050px;padding-left:70px;padding-right:70px}.layout{grid-template-columns:300px 1fr}}
@media(max-width:1000px){.masthead{padding:0 22px}.lesson{padding:32px 28px}.layout{grid-template-columns:240px minmax(0,1fr)}.sidebar{padding:24px 16px}.intro{gap:30px}.home{padding:42px 28px}.guide{grid-template-columns:1fr 1fr}}
@media(max-width:720px){html{scroll-padding-top:105px}.masthead{height:62px;padding:0 16px}.masthead nav{gap:14px;font-size:11px}.brand{font-size:12px}.brand b{font-size:24px;margin-right:6px}.home{padding:30px 20px}.intro{grid-template-columns:1fr;gap:20px;padding-bottom:28px}.intro h1{font-size:38px}.intro-stats{display:flex;gap:22px}.stat-row{flex:1;display:block}.stat-row span{display:block}.courses,.curriculum{grid-template-columns:1fr}.courses{margin:28px 0 38px}.course-card{padding:28px}.course-card+.course-card{border-left:0;border-top:1px solid #000}.course-card h2{font-size:28px}.course-card p{min-height:0}.section-label{display:block}.section-label .muted{font-size:12px;display:block;margin-top:8px}.guide{gap:15px}.layout{display:block}.sidebar{position:relative;top:0;height:auto;border-right:0;border-bottom:1px solid var(--line);display:none}.sidebar.open{display:block}.mobile-menu{display:block;position:sticky;top:62px;z-index:19;background:#f4f4f1;padding:8px 16px;border-bottom:1px solid #ccc;display:flex;justify-content:space-between;align-items:center}.mobile-menu button{font-size:12px;padding:5px 12px}.mobile-menu span{font-size:11px}.lesson{padding:28px 20px 45px}.lesson h1{font-size:30px}.lesson .subtitle{font-size:15px}.lesson-nav{gap:15px}.agenda div{padding:10px}.agenda b{font-size:19px}.lab{padding:18px}.lab h3{font-size:18px}.lab header{gap:10px}.theory h2,.section h2{font-size:24px}.theory p,.solution p{font-size:14px}.assignment{padding:18px}.footer{padding:22px 20px;font-size:11px}.module-link{padding:18px 0}.module-image{max-height:280px}.copybox pre{font-size:12px}.pager a{max-width:48%}}
@media print{.masthead,.sidebar,.mobile-menu,.lesson-nav,.copybar button,.grade-row button,.finish button,.pager,.toast,.tools,.skip{display:none!important}.layout{display:block}.lesson{max-width:none;padding:0}.footer{padding:12px 0}.lab,.theory,.quiz-card{break-inside:auto}body{font-size:11pt}.copybox pre{max-height:none;overflow:visible}.journal{min-height:120px}.module-image{max-height:250px}.section{margin:25px 0}a{text-decoration:none}.home{padding:0}.courses,.curriculum{display:block}}

/* Domain-first identity */
.brand{display:inline-flex;align-items:center;gap:14px;white-space:nowrap}.brand b{font-size:46px;line-height:1;letter-spacing:-3px;margin-right:0;font-weight:900}.brand span{font-size:18px;letter-spacing:-.7px;font-weight:700}.masthead{height:84px}.sidebar{top:84px;height:calc(100vh - 84px)}.layout{min-height:calc(100vh - 84px)}@media(max-width:720px){.masthead{height:72px;gap:12px;flex-wrap:nowrap}.brand{gap:8px}.brand b{font-size:39px;letter-spacing:-2px}.brand span{font-size:14px}.masthead nav{gap:10px;font-size:10px}.mobile-menu{top:72px}.sidebar{top:0;height:auto}.masthead nav a:first-child:not(:last-child){white-space:nowrap}}@media(max-width:360px){.masthead{padding:0 12px}.brand b{font-size:35px}.brand span{font-size:12px}.masthead nav{gap:8px;font-size:9px}}

.brand-stamp{display:flex;align-items:baseline;justify-content:space-between;gap:20px;padding:0 0 22px;line-height:1}.brand-stamp b{font-size:112px;font-weight:900;letter-spacing:-9px}.brand-stamp span{font-size:24px;font-weight:700;letter-spacing:-1px}@media(max-width:720px){html{scroll-padding-top:132px}.intro-stats{flex-wrap:wrap;gap:16px}.brand-stamp{flex-basis:100%;padding:6px 0 2px}.brand-stamp b{font-size:88px;letter-spacing:-7px}.brand-stamp span{font-size:25px}.stat-row{min-width:80px}}

/* Easy, slide-like theory reading */
.theory-overview{border:1px solid var(--ink);padding:22px 26px;margin:24px 0 34px;background:#fff}.theory-overview>strong{font-size:18px}.theory-overview ol{display:grid;grid-template-columns:1fr 1fr;gap:8px 28px;margin:15px 0 0;padding-left:24px}.theory-overview li{font-size:13px}.theory-overview a{text-decoration:none}.theory-overview a:hover{text-decoration:underline}.theory{position:relative;border:1px solid var(--line);padding:34px 36px;margin:22px 0;background:#fff}.theory+.theory{margin-top:26px}.theory .slide-number{font-size:11px;font-weight:800;letter-spacing:2px;color:#777}.theory h3{font-size:25px;margin:8px 0 22px}.theory .takeaway{font-size:18px;line-height:1.65;background:#171717;color:#fff;padding:18px 20px;margin:0 0 24px}.theory .takeaway strong{color:#fff}.theory .remember{border-left:3px solid #171717;background:#f2f2ef;padding:14px 18px;margin:24px 0 0;font-size:14px}.theory p{max-width:760px}.theory ul,.theory ol{padding-left:22px;margin:14px 0 20px}.theory li{margin:9px 0;line-height:1.75}.theory h4{margin-top:26px}.theory table{margin:20px 0}.theory td,.theory th{line-height:1.65}.theory-overview+ .theory{margin-top:0}.theory .steps{display:grid;grid-template-columns:repeat(3,1fr);gap:0;list-style:none;counter-reset:step;padding:0;margin:0 0 18px;border:1px solid var(--line)}.theory .steps li{counter-increment:step;margin:0;padding:16px 18px;line-height:1.55;border-right:1px solid var(--line);font-size:14px}.theory .steps li:last-child{border-right:0}.theory .steps li:before{content:"0" counter(step);display:block;font-size:10px;font-weight:800;letter-spacing:1px;color:#777;margin-bottom:6px}.theory .example,.theory .caution{margin:10px 0;padding:14px 17px;line-height:1.6;font-size:14px}.theory .example{background:var(--soft)}.theory .caution{border-left:3px solid var(--ink);background:#fff}.theory .example strong,.theory .caution strong{display:block;font-size:11px;letter-spacing:.08em;margin-bottom:3px}@media(max-width:720px){.theory-overview{padding:18px 20px}.theory-overview ol{grid-template-columns:1fr}.theory{padding:24px 20px;margin-left:0;margin-right:0}.theory h3{font-size:22px}.theory .takeaway{font-size:16px;padding:15px 16px}.theory .remember{padding:13px 15px}.theory .steps{grid-template-columns:1fr}.theory .steps li{border-right:0;border-bottom:1px solid var(--line);padding:13px 15px}.theory .steps li:last-child{border-bottom:0}}

/* Concept diagrams: monochrome, mobile-first SVG slides */
.concept-diagram{max-width:540px;margin:22px auto;padding:18px 20px 12px;border:1px solid var(--ink);background:#fff}.concept-diagram svg{display:block;width:100%;height:auto}.concept-diagram .svg-title{font:700 15px Pretendard,'Noto Sans KR',sans-serif;fill:#141414}.concept-diagram .svg-label{font:600 13px Pretendard,'Noto Sans KR',sans-serif;fill:#141414}.concept-diagram .svg-kicker{font:700 10px Pretendard,'Noto Sans KR',sans-serif;letter-spacing:.04em;fill:#666}.concept-diagram .svg-box{fill:#fff;stroke:#141414;stroke-width:1.2}.concept-diagram .muted-box{fill:#f4f4f1;stroke:#aaa}.concept-diagram .strong-box{fill:#efefeb;stroke:#141414;stroke-width:2}.concept-diagram .svg-line{stroke:#777;stroke-width:1.2;fill:none}.concept-diagram .svg-arrow{stroke:#777;stroke-width:1.2;fill:none}.concept-diagram .svg-divider{stroke:#c8c8c4;stroke-width:1;stroke-dasharray:4 4}@media(max-width:720px){.concept-diagram{margin:18px 0;padding:14px 10px 8px}.concept-diagram .svg-label{font-size:12px}.concept-diagram .svg-title{font-size:14px}}
.concept-diagram .svg-step{font:800 11px ui-monospace,monospace;letter-spacing:.08em;fill:#666}.practice-preview{margin-bottom:0;border-bottom:0}.practice-preview+.lab{margin-top:0;border-top:3px solid var(--ink)}
.lab-brief{font-size:14px;line-height:1.65;margin:16px 0}.lab-materials{margin:18px 0;border:1px solid var(--line);background:var(--soft)}.lab-materials>summary{padding:14px 16px;font-weight:700;font-size:13px;cursor:pointer}.lab-materials[open]>summary{border-bottom:1px solid var(--line)}.lab-materials>.copybox,.lab-materials>h4,.lab-materials>.steps{margin-left:16px;margin-right:16px}.more-checks{margin-top:10px;font-size:13px}.more-checks summary{cursor:pointer;font-weight:700}

/* Source-grounded lesson slides */
.slide-file{display:grid;grid-template-columns:110px 1fr;gap:16px;padding:16px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.slide-file strong,.slide-check strong,.slide-warning strong{font-size:12px;letter-spacing:.06em;text-transform:uppercase}
.slide-file span,.slide-check span,.slide-warning span{line-height:1.55}
.slide-steps{list-style:none;counter-reset:slide-step;margin:22px 0;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1px;background:var(--line);border:1px solid var(--line)}
.slide-steps li{counter-increment:slide-step;background:var(--paper);padding:46px 18px 18px;min-height:138px;position:relative;font-weight:700;line-height:1.45}
.slide-steps li::before{content:'0' counter(slide-step);position:absolute;top:16px;left:18px;font-size:12px;letter-spacing:.08em;color:var(--muted)}
.slide-check,.slide-warning{display:grid;grid-template-columns:190px 1fr;gap:16px;margin:0;padding:14px 16px;background:#f4f4f2;border-left:3px solid #111}
.slide-warning{margin-top:8px;background:#fff;border:1px solid #111;border-left:3px solid #111}
.lab-files{display:flex;align-items:center;flex-wrap:wrap;gap:8px;margin:16px 0;padding:12px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.lab-files strong{font-size:12px;letter-spacing:.06em;margin-right:4px}
.lab-files .download{font-size:13px;padding:8px 10px;background:#fff}
@media(max-width:760px){.slide-steps{grid-template-columns:1fr}.slide-steps li{min-height:auto;padding:40px 16px 16px}.slide-file,.slide-check,.slide-warning{grid-template-columns:1fr;gap:6px}.slide-check strong,.slide-warning strong{margin-bottom:2px}}

/* Publish refresh after custom-domain verification. */

.lesson-visual{margin:34px 0 48px}
.lesson-visual .module-image{max-height:none;aspect-ratio:16/9;object-fit:cover;border-color:#cfcfca}
.lesson-visual figcaption{font-size:12px;color:#666;margin-top:10px}
.concept-figure{margin:44px 0 52px;padding-top:22px;border-top:1px solid var(--ink)}
.concept-figure h2{font-size:24px;margin:8px 0 18px}
.concept-scroll{overflow-x:auto;overscroll-behavior-x:contain;padding-bottom:5px}
.concept-map{display:block;width:100%;min-width:720px;height:auto;background:#f5f5f2;border:1px solid #d7d7d2}
.concept-box{fill:#fff;stroke:#202020;stroke-width:1.2}
.concept-num{font:700 12px Pretendard,'Noto Sans KR',Arial,sans-serif;letter-spacing:1px;fill:#c9511d}
.concept-label{font:700 16px/1.5 Pretendard,'Noto Sans KR',Arial,sans-serif;color:#171717;display:flex;align-items:center;height:100%;word-break:keep-all}
.concept-arrow{stroke:#222;stroke-width:1.4}
.concept-arrowhead{fill:#222}
@media(max-width:760px){.lesson-visual{margin:26px 0 36px}.concept-figure{margin:34px 0 42px}.concept-figure h2{font-size:21px}.concept-map{min-width:680px}}