/* Shared visual system for the study home, library, and dated lessons. */
:root{--green:#237b61;--forest:#193e35;--ink:#17202c;--muted:#58636f;--line:#dce3e5;--sage:#e7f0e9;--soft:#f4f6f7;--radius:10px;font-family:"Segoe UI",Arial,sans-serif;font-size:17px;line-height:1.6;color:var(--ink);background:#fff;color-scheme:light}
*{box-sizing:border-box}body{margin:0}h1,h2,h3,p{margin:0}h1,h2,h3{line-height:1.22}h1,h2,.site-brand,.focus-title{font-family:Georgia,"Times New Roman",serif;letter-spacing:-.035em}h1{font-size:clamp(1.85rem,3.6vw,2.65rem)}h2{font-size:clamp(1.5rem,2.7vw,2rem)}h3{font-size:1.05rem}a{color:var(--green);text-underline-offset:4px}button,input,select,textarea{font:inherit}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{cursor:default;opacity:.45}:focus-visible{outline:3px solid #72bfa7;outline-offset:4px}[hidden]{display:none!important}
.site-header{border-bottom:1px solid var(--line);background:#fff}.header-inner{max-width:1120px;margin:auto;min-height:76px;padding:0 32px;display:flex;align-items:center;justify-content:space-between;gap:24px}.site-brand{color:var(--ink);text-decoration:none;font-size:1.4rem;font-weight:700;white-space:nowrap}.site-brand span{font-weight:400;color:var(--muted)}.site-links{display:flex;gap:28px;align-items:center}.site-links a{padding:25px 0 22px;border-bottom:3px solid transparent;color:var(--muted);text-decoration:none;font-size:.86rem}.site-links a:hover,.site-links a[aria-current=page]{color:var(--forest);border-bottom-color:var(--green)}
.home-main,.library-main{max-width:1064px;margin:auto;padding:48px 32px 30px}.home-intro{text-align:center;margin-bottom:32px}.intro{margin-top:12px;color:var(--muted);font-size:1.1rem}.featured-lesson{display:grid;grid-template-columns:minmax(0,1fr) 225px;gap:32px;padding:30px 32px;background:var(--sage);border-radius:var(--radius)}.lesson-date{font-size:.83rem;color:var(--forest);margin-bottom:12px}.featured-lesson h2{max-width:630px}.featured-lesson .description{margin-top:10px;color:#354a41}.featured-lesson .button{margin-top:22px}.lesson-progress{align-self:center;border-left:1px solid #cbdcd2;padding-left:28px;font-size:.85rem}.lesson-progress progress{display:block;width:100%;height:7px;margin:12px 0 22px}.homework-link{display:block;padding-top:16px;border-top:1px solid #cbdcd2;color:var(--forest)}progress{accent-color:var(--green);border:0;border-radius:10px;background:#d6dedb}progress::-webkit-progress-bar{background:#d6dedb;border-radius:10px}progress::-webkit-progress-value{background:var(--green);border-radius:10px}
.button{border:1px solid #bcc7cc;border-radius:8px;background:#fff;color:var(--ink);min-height:44px;padding:9px 17px;display:inline-flex;align-items:center;justify-content:center;gap:10px;text-decoration:none;font-size:.9rem;font-weight:600;line-height:1.4}.button:hover{background:#f2f6f4}.button.primary{background:var(--green);color:#fff;border-color:var(--green)}.button.primary:hover{background:#1b634e}.icon{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}.focus-section{margin-top:38px}.focus-section h2{font-size:1.75rem;margin-bottom:14px}.focus-link{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:18px 16px;border-top:1px solid var(--line);text-decoration:none;color:var(--ink)}.focus-link:last-child{border-bottom:1px solid var(--line)}.focus-link:hover{background:#f7faf8}.focus-title{display:block;font-size:1.35rem;font-weight:700}.focus-description{display:block;font-size:.92rem;color:var(--muted);margin-top:2px}.site-footer{margin-top:28px;padding-top:18px;font-size:.78rem;color:var(--muted)}.skip{position:absolute;left:12px;top:-100px;background:#fff;padding:12px;z-index:20}.skip:focus{top:10px}.muted{color:var(--muted)}.small{font-size:.86rem}
.library-list{margin-top:36px}.library-year{font-size:.9rem;font-weight:600;color:var(--forest);margin-bottom:12px}.library-lesson{display:grid;grid-template-columns:120px minmax(0,1fr) auto;gap:26px;align-items:center;padding:28px 0;border-block:1px solid var(--line)}.library-lesson h2{font-size:1.5rem}.library-lesson p{color:var(--muted);font-size:.92rem;margin-top:8px}.library-lesson time{font-size:.95rem;font-weight:600}.library-lesson .day{font-size:.8rem;color:var(--muted)}.migration{margin-top:24px;background:var(--soft);border-left:3px solid var(--green);padding:18px 22px}.migration p{margin:10px 0;font-size:.9rem}
/* Lesson chrome uses the same header and a single, narrow reading column. */
.lesson-page .shell{display:block;min-height:0}.lesson-page .sidebar{position:static;height:auto;background:#fff;color:var(--ink);padding:0;display:block;max-width:1000px;margin:0 auto}.class-heading{padding:26px 32px 18px}.class-heading .lesson-date{margin:0 0 7px}.class-heading h1{font-size:1.8rem}.lesson-page .nav{display:flex;justify-content:space-between;gap:8px;padding:0 32px;border-bottom:1px solid var(--line);overflow:visible}.lesson-page .nav button{border:0;border-bottom:3px solid transparent;border-radius:0;background:transparent;color:var(--muted);padding:13px 5px;min-height:48px;font-size:.88rem;gap:0}.lesson-page .nav button .icon{display:none}.lesson-page .nav button:hover{background:#f7faf8;color:var(--forest)}.lesson-page .nav button.active{background:transparent;color:var(--green);border-bottom-color:var(--green);font-weight:650}.lesson-page .progress{display:flex;align-items:center;gap:16px;max-width:936px;margin:0 auto;padding:12px 0 0;border:0;color:var(--muted);font-size:.76rem}.lesson-page .progress progress{display:block;width:110px;height:5px;margin:0}.lesson-page .main{max-width:1000px;padding:22px 32px 40px;margin:0 auto}.lesson-page .content{max-width:none}.lesson-page .top{display:flex;flex-direction:row;align-items:flex-start;justify-content:space-between;margin-bottom:22px;gap:20px}.lesson-page .top h2{font-size:1.8rem}.lesson-page .subtitle{font-size:.96rem;margin-top:7px}.reading-settings{margin-left:auto;flex-shrink:0;max-width:100%;font-size:.85rem}.reading-settings>summary{cursor:pointer;min-height:44px;display:flex;align-items:center;gap:8px;color:var(--muted);list-style:none}.reading-settings>summary::after{content:'';width:7px;height:7px;border-right:1.5px solid;border-bottom:1.5px solid;transform:rotate(45deg);margin-left:6px;margin-top:-4px}.reading-settings[open]>summary::after{transform:rotate(225deg);margin-top:4px}.reading-settings[open]{flex:1}.lesson-page .utilities{padding:10px 0 16px;display:flex;flex-wrap:wrap;gap:18px}.lesson-page .pronunciation-help{margin:0 0 14px;font-size:.82rem}.lesson-page .toggle{font-size:.85rem}.lesson-page .top:has(.reading-settings[open]){flex-wrap:wrap}.lesson-page[data-page=learn] .page-intro{display:none}.lesson-page[data-page=learn] .top{margin-bottom:8px}.topic-picker{display:flex;align-items:center;gap:14px;margin-bottom:20px;flex-wrap:wrap}.topic-picker label{color:var(--muted);font-size:.85rem}.topic-picker select{border:1px solid var(--line);border-radius:6px;padding:8px 32px 8px 10px;background:#fff;color:var(--forest);font-size:.86rem;max-width:100%;min-height:44px}.topic-status{font-size:.8rem;color:var(--green)}.lesson-page .content>h2{font-size:1.85rem}.lesson-page .lead{font-size:1rem;margin:9px 0 20px}.lesson-page .example{padding:24px 28px;margin:22px 0 14px;border-radius:8px;background:var(--sage);position:relative}.lesson-page .example .cn{font-size:clamp(1.65rem,3.1vw,2.5rem);line-height:1.5}.lesson-page .example .pinyin{font-size:1.1rem}.lesson-page .example .thai-guide{font-size:1.05rem}.lesson-page .example .english{font-size:1rem}.lesson-page .example .button{background:transparent;color:var(--forest);border-color:#95afa1;margin-top:14px}.lesson-page .breakdown{background:transparent;padding:12px 0;margin-bottom:16px}.lesson-page .word .cn{font-size:1.2rem}.lesson-page .word span{font-size:.85rem}.lesson-page .notes{gap:28px;margin:20px 0}.lesson-page .notes>div+div{padding-left:28px;border-left:1px solid var(--line)}.lesson-page .notes h3{font-family:Georgia,"Times New Roman",serif;font-size:1.2rem}.lesson-page .notes p{font-size:.92rem}.lesson-page .extra{margin-top:16px}.lesson-page .extra>summary{padding:12px 14px;background:#f2f6f3;border-radius:6px;font-size:.9rem;min-height:44px}.lesson-page .extra[open]>summary{margin-bottom:16px}.lesson-page .bottom{margin-top:20px;padding-top:18px}.lesson-page .toast{left:50%}.lesson-page .toolbar,.lesson-page .tabs{margin:18px 0}.lesson-page .flash{min-height:265px;border:0}.lesson-page .callout{font-size:.94rem}.lesson-page .question{font-family:"Segoe UI",Arial,sans-serif;letter-spacing:normal}.lesson-page .sr-only:focus{position:fixed;left:12px;top:12px;width:auto;height:auto;clip:auto;margin:0;padding:12px;background:white;z-index:50}.lesson-page .saved-item>div{min-width:0;overflow-wrap:anywhere}.lesson-page .field{min-width:0}.lesson-page .homework-summary{margin-top:0}.lesson-page .homework-summary p{margin-top:5px}.lesson-page .source-picture{max-width:580px}.lesson-page .reading-settings .pronunciation-help[open]{padding:14px}.lesson-page .content{overflow-wrap:anywhere}
@media(max-width:720px){:root{font-size:16px}.header-inner{padding:0 20px;min-height:64px;gap:14px}.site-brand{font-size:1.2rem}.site-brand span{display:none}.site-links{gap:18px}.site-links a{padding:20px 0 17px;font-size:.8rem}.home-main,.library-main{padding:32px 20px 24px}.home-intro{text-align:left;margin-bottom:25px}.home-intro h1{max-width:350px}.intro{font-size:1rem}.featured-lesson{grid-template-columns:1fr;gap:24px;padding:24px}.featured-lesson h2{font-size:1.7rem}.lesson-progress{border-left:0;border-top:1px solid #cbdcd2;padding:18px 0 0}.lesson-progress progress{margin:10px 0 16px}.homework-link{padding-top:12px}.focus-section{margin-top:30px}.focus-link{padding:17px 4px}.focus-section h2{font-size:1.6rem}.focus-title{font-size:1.3rem}.library-lesson{grid-template-columns:1fr;gap:12px;padding:24px 0}.library-lesson .button{justify-self:start}.library-lesson .day{display:inline;margin-left:8px}.class-heading{padding:22px 20px 12px}.class-heading h1{font-size:1.5rem}.lesson-page .nav{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:0;padding:0 16px}.lesson-page .nav button{justify-content:center;font-size:.8rem;min-height:44px;padding:9px 2px}.lesson-page .progress{margin:0 20px;padding-top:11px;justify-content:space-between;font-size:.74rem}.lesson-page .progress progress{width:88px}.lesson-page .main{padding:12px 20px 32px}.lesson-page .top{gap:10px;flex-wrap:wrap;margin-bottom:18px}.lesson-page .page-intro{width:100%}.reading-settings{margin-left:0}.lesson-page .utilities{gap:14px}.lesson-page .content>h2{font-size:1.6rem}.topic-picker{gap:8px;margin-bottom:16px}.topic-picker select{width:100%}.lesson-page .example{padding:20px;margin-top:18px}.lesson-page .example .cn{font-size:1.9rem}.lesson-page .example .pinyin{font-size:1rem}.lesson-page .example .thai-guide{font-size:1rem}.lesson-page .notes{gap:18px}.lesson-page .notes>div+div{padding-left:0;border:0}.lesson-page .bottom .button{font-size:.82rem;padding:10px 12px}.lesson-page .flash .cn{font-size:3rem}.lesson-page .builder-fields{gap:16px;margin:20px 0}.lesson-page .source-links .button{width:100%}.lesson-page .turn{grid-template-columns:28px minmax(0,1fr)}.lesson-page .vocab-actions{gap:8px}.lesson-page .vocab-actions .button{font-size:.8rem;padding:9px 10px}}
@media(max-width:360px){.header-inner{padding-inline:16px}.site-links{gap:12px}.site-brand{font-size:1.08rem}.home-main,.library-main{padding-inline:16px}.featured-lesson{padding:20px}.lesson-page .main{padding-inline:16px}.lesson-page .example{padding:16px}.lesson-page .example .cn{font-size:1.65rem}}
.lesson-page[data-page=sources] .reading-settings{display:none}
@media(min-width:721px){.lesson-page[data-page=learn] .top:not(:has(details[open])){float:right;margin:0}.lesson-page[data-page=learn] .top:not(:has(details[open]))+.content .topic-picker{width:calc(100% - 190px)}.lesson-page .content>h2{clear:both}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}
@media print{.site-header,.reading-settings,.lesson-page .sidebar,.skip{display:none!important}.lesson-page .main{padding:0}.lesson-page .top{display:block}}