@import url('https://fonts.googleapis.com/css2?family=Manrope:wght@400;500;600;700;800&family=Golos+Text:wght@400;500;600;700&display=swap');
:root{font-family:'Manrope','Segoe UI',Arial,sans-serif;color:#1a3152;background:#f5f8fc;font-synthesis:none}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0}button,input{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid #70b3ff;outline-offset:3px}.design-shell{min-height:100vh}.design-header{height:70px;display:flex;align-items:center;gap:30px;padding:0 30px;background:#fff;border-bottom:1px solid #e8eef6;box-shadow:0 3px 14px #18466b08;position:sticky;top:0;z-index:10}.logo{display:grid;grid-template-columns:36px auto;grid-template-rows:22px 15px;align-items:center;min-width:220px;column-gap:8px}.brandmark{grid-row:1/3;display:grid;place-items:center;width:33px;height:33px;border-radius:10px;background:#1a70cd;color:#fff;font-size:25px}.logo-text{font-size:15px;font-weight:800;letter-spacing:.015em;color:#14559e}.logo-sub{font-size:11px;color:#8494a6}.head-links{display:flex;align-items:center;gap:25px;font-size:13px;color:#64768a;white-space:nowrap}.head-active{color:#175eaf;font-weight:700}.search-trigger{margin-left:auto;min-width:220px;width:340px;text-align:left;background:#f5f8fc;border:1px solid #e2eaf4;border-radius:9px;padding:11px 13px;color:#8a9aad;font-size:12px}.avatar-trigger{width:36px;height:36px;border:0;background:#eaf3ff;color:#1764ba;border-radius:50%;font-size:21px}.design-layout{display:grid;grid-template-columns:258px minmax(0,760px) 228px;gap:22px;max-width:1350px;margin:0 auto;padding:24px 20px 70px;align-items:start}.design-sidebar,.design-main,.right-card{background:#fff;border:1px solid #e6edf6;box-shadow:0 6px 24px #1b52850a;border-radius:12px}.design-sidebar{padding:17px 12px;position:sticky;top:88px;max-height:calc(100vh - 105px);overflow:auto;scrollbar-width:thin}.side-intro{font-size:10px;letter-spacing:.095em;color:#91a2b4;padding:7px 12px}.library-head{font-size:14px;font-weight:750;color:#1a5eaf;padding:12px;background:#edf5ff;border-radius:8px;margin:6px 0 24px}.side-label{font-size:10px;color:#8296ab;font-weight:700;letter-spacing:.09em;padding:0 12px;margin-bottom:8px}.group-title,.side-page{display:block;width:100%;text-align:left;background:transparent;border:0;border-radius:7px;line-height:1.43}.group-title{color:#253f60;font-size:12.5px;font-weight:700;padding:11px 10px}.side-page{color:#586c83;font-size:12px;padding:10px 9px 10px 21px}.group-title:hover,.side-page:hover{background:#f4f8fc}.side-page.is-active{color:#0c65c5;background:#eaf3ff;font-weight:700;box-shadow:inset 3px 0 #1276dd}.side-separator{height:1px;background:#e8eef5;margin:13px 4px}.design-main{padding:27px 32px 29px;min-width:0}.breadcrumbs{font-size:11px;color:#8092a6;line-height:1.6;margin-bottom:21px}.article-heading h1{font-size:25px;line-height:1.26;letter-spacing:-.025em;margin:0 0 13px;color:#172e50}.metadata{font-size:11.5px;color:#7b90a6;display:flex;gap:20px}.article-lead{font-size:15px;line-height:1.63;color:#405673;margin:24px 0 20px}.hero{display:grid;grid-template-columns:1fr 1fr;min-height:150px;border-radius:10px;overflow:hidden;background:linear-gradient(115deg,#ebf5ff 0%,#dceefa 55%,#b1d3ef 100%);margin:21px 0 26px}.hero-text{padding:24px 24px 20px;align-self:center;color:#1d4369;font-size:15px;line-height:1.5;font-weight:600}.hero-kicker{font-size:10px;color:#4e85b7;letter-spacing:.11em;margin-bottom:9px}.hero-visual{background:linear-gradient(125deg,#6db5df 0%,#0f5d9e 100%);display:flex;flex-direction:column;align-items:center;justify-content:center;position:relative;overflow:hidden;color:#fff}.hero-visual:after{content:'';width:170px;height:170px;border:1px solid #ffffff44;border-radius:35px;transform:rotate(28deg);position:absolute;right:-20px;top:-90px}.hero-visual-icon{font-size:50px;opacity:.9}.hero-visual-label{font-size:9px;font-weight:700;letter-spacing:.07em;margin-top:6px;text-align:center;padding:0 9px}.lesson-body{font-size:14px;line-height:1.59;color:#3d5067}.lesson-section{margin:0 0 23px}.lesson-section h2{font-size:18px;color:#183352;margin:0 0 9px;letter-spacing:-.01em;scroll-margin-top:95px}.lesson-section p{margin:0 0 13px}.principle{display:flex;gap:12px;padding:17px;background:#eff6ff;border:1px solid #d0e4fc;border-radius:9px;margin:18px 0 2px}.principle-icon{display:grid;place-items:center;flex:none;width:35px;height:35px;color:#1171d4;background:#deedff;border-radius:9px;font-size:26px}.principle strong{font-size:13px;color:#153e72}.principle p{margin:7px 0 0;font-size:13px;line-height:1.6}.detail-accordion{border:1px solid #e0eaf4;border-radius:9px;background:#fbfdff;margin:24px 0}.detail-accordion summary{font-size:13px;font-weight:700;padding:15px 18px;cursor:pointer}.detail-accordion p{font-size:13px;line-height:1.6;padding:0 18px 15px;margin:0}.lesson-pager{display:grid;grid-template-columns:1fr 1fr;gap:10px;border-top:1px solid #e8eef5;padding-top:16px;margin-top:26px}.pager-action{background:#fff;border:1px solid #deebf8;border-radius:8px;padding:13px;color:#1b629f;text-align:left;font-size:12px;line-height:1.4}.pager-action:last-child{text-align:right}.pager-action:hover{background:#eff7ff}.design-aside{display:flex;flex-direction:column;gap:15px;position:sticky;top:88px}.right-card{padding:19px 15px}.card-title{font-size:13px;display:block;color:#213c5d;margin-bottom:14px}.toc-entry{display:block;text-decoration:none;color:#657a92;font-size:12px;line-height:1.5;padding:10px 0 10px 11px;border-left:2px solid #ebf0f6}.toc-entry:hover{color:#0a69c1;border-color:#1974d0}.related-link{display:block;background:transparent;border:0;border-top:1px solid #edf1f6;padding:13px 1px;font-size:11.5px;line-height:1.5;color:#425b77;text-align:left;width:100%}.related-link:hover{color:#1268c4}.help-card{background:#f2f8ff}.help-card strong{display:block;font-size:13px;margin-bottom:7px}.help-card p{font-size:12px;line-height:1.6;color:#69809a;margin:0}.help-icon{width:32px;height:32px;border-radius:9px;background:#dcecff;color:#1670c9;display:grid;place-items:center;margin-bottom:11px}.search-panel{display:flex;gap:9px;background:#f3f8ff;border:1px solid #dbeafa;border-radius:10px;padding:12px;margin-bottom:22px}.search-panel input{flex:1;min-width:0;border:1px solid #d4e2f1;border-radius:7px;padding:11px;font-size:13px}.blue-btn{background:#1169c5;color:white;border:0;border-radius:7px;padding:9px 15px}.backdrop,.mobile-trigger,.mobile-bottom{display:none}@media(max-width:1200px){.design-layout{grid-template-columns:230px minmax(0,1fr)}.design-aside{display:none}.head-links{gap:15px}.search-trigger{width:260px}}@media(max-width:780px){.design-header{padding:0 13px;height:59px;gap:11px}.logo{min-width:0;grid-template-columns:30px auto;column-gap:6px}.brandmark{width:29px;height:29px}.logo-text{font-size:12px}.logo-sub{font-size:9px}.head-links,.search-trigger{display:none}.mobile-trigger{display:block;background:transparent;border:0;font-size:21px;color:#235782;padding:5px}.avatar-trigger{margin-left:auto}.design-layout{display:block;padding:13px 10px 86px}.design-sidebar{position:fixed;top:0;left:0;bottom:0;z-index:30;width:min(320px,84vw);max-height:none;border-radius:0;transform:translateX(-110%);transition:transform .2s ease;box-shadow:7px 0 30px #15395b18}.design-sidebar.drawer-open{transform:translateX(0)}.backdrop.visible{display:block;background:#1028468c;border:0;position:fixed;inset:0;z-index:20}.design-main{padding:20px 17px 28px;border-radius:10px}.article-heading h1{font-size:22px}.article-lead{font-size:14px;margin-top:19px}.hero{min-height:145px}.hero-text{padding:15px;font-size:13px}.hero-visual-icon{font-size:38px}.hero-visual-label{font-size:8px}.lesson-section h2{font-size:17px}.lesson-body{font-size:14px}.metadata{gap:12px}.mobile-bottom{display:flex;position:fixed;bottom:0;left:0;right:0;z-index:11;background:white;border-top:1px solid #e3ecf7;padding:10px 12px;gap:8px;box-shadow:0 -4px 22px #245b8410}.mobile-bottom button{flex:1;border:0;background:#edf5ff;color:#28659a;border-radius:9px;padding:12px 6px;font-size:12px}.mobile-bottom button.next{background:#1170d0;color:#fff}}@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
/* Design revision: tighter exterior spacing, professional icon rhythm */
.design-layout{gap:15px;padding-top:17px;grid-template-columns:258px minmax(0,760px) 228px}
.design-aside{gap:11px;top:84px}
.design-sidebar{top:84px}
.right-card{padding:16px 15px}
.toc-entry{padding:7px 0 7px 10px}
.related-link{padding:10px 1px}
.design-main{padding:24px 29px}
.breadcrumbs{margin-bottom:17px}
.article-lead{margin:19px 0 15px}
.hero{margin:16px 0 20px;min-height:145px}
.lesson-section{margin-bottom:15px}
.lesson-section h2{margin-bottom:7px}
.principle{margin:13px 0 0;padding:14px}
.detail-accordion{margin:17px 0}
.lesson-pager{margin-top:18px;padding-top:13px}
.group-title{display:flex;align-items:center;gap:8px}
.group-title .chevron{margin-left:auto;transform:rotate(-90deg);transition:transform .15s}
.group-title .chevron.open{transform:rotate(0deg)}
.ui-icon{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;color:#1670cc;vertical-align:middle}
.ui-icon svg{width:17px;height:17px}
.pager-action{display:flex;align-items:center;justify-content:flex-start;gap:9px}
.pager-action:last-child{justify-content:flex-end}
.pager-action .ui-icon{background:#eaf3ff;border-radius:7px;padding:6px;min-width:32px;height:32px}
.pager-action .ui-icon svg{width:17px;height:17px}
.search-trigger{display:flex;align-items:center;gap:8px}
.avatar-trigger{display:grid;place-items:center}
.avatar-trigger .ui-icon svg{width:20px;height:20px}
.card-title{display:flex;align-items:center;gap:8px}
.hero-visual{background:#2877b7}
.switchgear-img{width:100%;height:100%;object-fit:cover;object-position:center;display:block}
@media(max-width:780px){.design-layout{padding:10px 10px 82px}.design-main{padding:18px 16px}.article-lead{margin:16px 0}.hero{margin:14px 0 17px}.lesson-section{margin-bottom:14px}.design-sidebar{top:0}.pager-action{font-size:11px}.pager-action .ui-icon{min-width:27px;height:27px;padding:4px}}

/* Typography polish */
.design-main,.design-sidebar,.design-aside{font-family:'Manrope','Segoe UI',Arial,sans-serif}.design-main{letter-spacing:0}.lesson-body{line-height:1.63}.side-page{line-height:1.47}.group-title{line-height:1.4}.article-heading h1{font-weight:700;letter-spacing:-.025em}

/* Approved type pairing: Manrope UI, Golos Text extended reading */
.lesson-body,.article-lead,.detail-accordion p,.principle p{font-family:'Golos Text','Segoe UI',Arial,sans-serif}
.design-header,.design-sidebar,.design-aside,.article-heading,.breadcrumbs,.metadata,.lesson-pager{font-family:'Manrope','Segoe UI',Arial,sans-serif}