:root{--bg:#f2f5ef;--surface:#fcfdfb;--ink:#293d32;--muted:#647166;--line:#d9e2d6;--accent:#47664e;--soft:#e3ebdf;font-family:Arial,Helvetica,sans-serif;color:var(--ink);background:var(--bg);font-size:16px}*{box-sizing:border-box}body{margin:0}button,input,textarea{font:inherit}button,a,input,textarea,summary{-webkit-tap-highlight-color:transparent}button{cursor:pointer;transition:background .15s}button:disabled{opacity:.55;cursor:wait}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid #769774;outline-offset:4px}header{height:100px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 5%;gap:20px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--ink);font-family:Georgia,serif;font-size:32px;font-weight:bold}.mark{background:var(--accent);color:var(--bg);width:42px;height:42px;display:inline-flex;justify-content:center;align-items:center;font:italic 32px Georgia,serif;border-radius:10px}.brand-note{font:14px Arial,sans-serif;font-weight:normal;color:var(--muted);margin-left:20px}.outline,.primary{border:1px solid var(--line);border-radius:7px;padding:13px 20px;background:transparent;color:var(--ink);font-size:14px;line-height:1.4}.outline:hover{background:var(--soft)}.primary{background:var(--accent);border-color:var(--accent);color:white}.primary:hover{background:#354f3b}.layout{max-width:1500px;margin:auto;display:grid;grid-template-columns:260px minmax(0,1fr);min-height:calc(100vh - 100px)}aside{border-right:1px solid var(--line);padding:44px 25px 30px 30px}.eyebrow{font-size:12px;letter-spacing:1.7px;color:var(--muted);font-weight:600}nav{display:grid;gap:9px;margin-top:23px}nav button{display:flex;align-items:center;gap:15px;padding:15px 14px;text-align:left;border:0;border-radius:7px;background:transparent;color:var(--muted)}nav button.active{background:var(--soft);color:var(--ink)}nav button:hover{background:#e9efe5}.nav-number{font:italic 17px Georgia,serif;opacity:.7}.history{margin-top:32px;border:0;border-top:1px solid var(--line);padding:26px 14px;width:100%;display:flex;justify-content:space-between;background:transparent;color:var(--ink);text-align:left}.aside-note{margin:100px 14px 0;color:var(--muted);font:italic 17px/1.7 Georgia,serif}main{padding:30px 7% 0;min-width:0}.topline{display:flex;justify-content:space-between;gap:12px;font-size:12px;color:var(--muted);padding-bottom:40px}.heading{display:flex;justify-content:space-between;align-items:center;gap:20px}h1{font:normal clamp(28px,3vw,42px)/1.2 Georgia,serif;margin:12px 0 20px;letter-spacing:-.7px}.time{white-space:nowrap;font-size:12px;border:1px solid var(--line);padding:8px 10px;border-radius:20px}.brief{font-size:16px;line-height:1.85;max-width:750px;margin:0 0 20px}.hint{font-size:14px;color:var(--muted);margin-bottom:28px}.hint summary{cursor:pointer;width:fit-content}.hint p{line-height:1.7;padding-left:16px;max-width:700px}.paper{background:var(--surface);border:1px solid var(--line);border-radius:8px;box-shadow:0 6px 24px #293d3204}.paper-top,.paper-bottom{display:flex;justify-content:space-between;gap:14px;font-size:12px;color:var(--muted);padding:20px 26px}.paper-top label{color:var(--ink);font-size:14px}.paper-top{border-bottom:1px solid #edf0e9}textarea{display:block;width:100%;resize:vertical;min-height:280px;border:0;outline:none;background:transparent;padding:24px 26px;font:19px/1.85 Georgia,'Times New Roman',serif;color:var(--ink)}textarea:focus{box-shadow:inset 3px 0 #a3b99b}textarea::placeholder{color:#929e90}.paper-bottom{padding-top:12px}.actions{display:flex;justify-content:space-between;gap:15px;margin-top:20px}.actions .primary span{margin-left:20px}.small{font-size:12px;color:var(--muted);margin-top:14px}.examples{border-top:1px solid var(--line);margin-top:38px;padding-top:28px;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:16px}.examples h2{font:normal 25px Georgia,serif;margin:10px 0}.examples p{font-size:14px;color:var(--muted);line-height:1.7;max-width:480px;margin-bottom:0}#example-list{width:100%}.example{background:#eaf0e6;border-radius:8px;padding:22px;margin-top:14px}.example h3{font-size:14px;margin:0 0 12px}.example p{font:17px/1.8 Georgia,serif;color:var(--ink);max-width:none;white-space:pre-line}.examples .outline{white-space:nowrap}footer{border-top:1px solid var(--line);margin-top:42px;padding:23px 0;display:flex;justify-content:space-between;font-size:12px;color:var(--muted)}footer span:first-child{font:italic 17px Georgia,serif}dialog{width:min(440px,calc(100% - 28px));border:1px solid var(--line);border-radius:12px;padding:34px;background:var(--surface);color:var(--ink)}dialog::backdrop{background:#1c302c65;backdrop-filter:blur(3px)}dialog h2{font:28px Georgia,serif}dialog p{color:var(--muted);font-size:14px;line-height:1.7}.close{position:absolute;right:16px;top:12px;background:none;border:0;color:var(--muted);font-size:28px}form label{display:block;font-size:14px;margin:18px 0}input{display:block;width:100%;border:1px solid var(--line);border-radius:6px;background:white;padding:13px;margin-top:9px;color:var(--ink)}input:focus{outline:2px solid #a3b99b}form .primary{width:100%}.text-button{display:block;background:none;border:0;color:var(--accent);font-size:13px;margin:18px auto 0;line-height:1.5}#auth-message{color:#79422e}#toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:var(--ink);color:white;padding:16px 24px;border-radius:8px;max-width:90%;font-size:14px;box-shadow:0 6px 20px #0002;z-index:5}.work{width:100%;text-align:left;padding:24px;border:1px solid var(--line);border-radius:8px;background:var(--surface);color:var(--ink);margin:0 0 14px}.work strong{display:block;font:24px Georgia,serif}.work p{white-space:pre-wrap;line-height:1.6;overflow-wrap:anywhere}.work small{color:var(--muted)}[hidden]{display:none!important}@media(min-width:1500px){main{padding-left:85px;padding-right:85px}}@media(max-width:900px){.brand-note{display:none}.layout{grid-template-columns:200px minmax(0,1fr)}aside{padding:35px 15px}main{padding:25px 5% 0}.time{display:none}.topline #progress{display:none}.actions .primary span{display:none}}@media(max-width:640px){header{height:80px;padding:0 20px}.brand{font-size:27px}header .outline{padding:10px;font-size:12px}.layout{display:block}aside{padding:20px 18px;border-right:0;border-bottom:1px solid var(--line)}aside>.eyebrow,.aside-note{display:none}nav{display:flex;overflow-x:auto;margin:0;gap:6px;padding:3px 0}nav button{white-space:nowrap;padding:12px;font-size:14px}.nav-number{display:none}.history{margin:10px 0 0;padding:12px;border-top:0;font-size:14px}main{padding:22px 20px 0}.topline{padding-bottom:24px}h1{font-size:32px}.paper-top,.paper-bottom{padding:16px;font-size:12px}#save-state{max-width:55%;text-align:right}textarea{padding:20px 16px;font-size:18px;min-height:310px}.actions{flex-direction:column}.actions button{width:100%}.examples{margin-top:28px}.examples .outline{width:100%}footer{gap:15px}.paper-bottom span:last-child{display:none}}
/* Shared responsive surfaces */
html{scroll-behavior:smooth}h2{font:normal 27px/1.3 Georgia,serif}h3{font-weight:normal}p, h1,h2,h3,strong{overflow-wrap:anywhere}.header-actions{display:flex;gap:10px;align-items:center;min-width:0}.header-actions #profile{max-width:220px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.home-link{display:block;color:var(--ink);text-decoration:none;margin:0 14px 30px;font-size:16px}.welcome{padding:30px 0 48px;border-bottom:1px solid var(--line);margin-bottom:34px}.welcome h1{font-size:clamp(34px,4.2vw,58px);line-height:1.12;max-width:850px}.welcome .brief{max-width:630px;margin:24px 0}.welcome .primary{font-size:16px;padding:15px 24px}.card-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.category-card,.task-card{text-align:left;border:1px solid var(--line);background:var(--surface);padding:26px;border-radius:9px;color:var(--ink);min-width:0}.category-card:hover,.task-card:hover{background:var(--soft)}.category-card h3{font:27px Georgia,serif;margin:16px 0 10px}.category-card p{font-size:14px;color:var(--muted);margin:0}.task-card{display:flex;flex-direction:column;gap:14px}.task-card h2,.task-card p{margin:0}.task-card p{font-size:16px;line-height:1.7}.card-link{margin-top:auto;padding-top:10px;font-size:14px;color:var(--accent)}.comparing{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.answer-text{padding:8px 26px 24px;margin:0;font:19px/1.85 Georgia,serif;white-space:pre-wrap;overflow-wrap:anywhere}.comparing .paper-top{flex-wrap:wrap}.comments{border-top:1px solid var(--line);margin-top:36px;padding-top:24px}.comments .small{font-size:14px;line-height:1.7}.comments textarea,dialog textarea{min-height:130px;border:1px solid var(--line);background:var(--surface);border-radius:6px;font:16px/1.6 Arial,sans-serif;padding:15px;margin:10px 0 16px}.comment{padding:24px 0;border-bottom:1px solid var(--line)}.comment strong{font-size:16px}.comment p{white-space:pre-wrap;line-height:1.7}.comment-date{display:block;font-size:12px;color:var(--muted);margin-top:8px}.compact-form{max-width:460px}.history-previous{margin-top:24px;border-top:1px solid var(--line);padding-top:18px}.history-previous summary{cursor:pointer}.work>p{font:18px/1.8 Georgia,serif}.work small{display:block;margin-top:12px}.section-heading,.admin-row{display:flex;align-items:center;justify-content:space-between;gap:18px}.admin-row{border-bottom:1px solid var(--line);padding:20px 0}.admin-row>div{min-width:0}.admin-row .outline{flex-shrink:0}.admin-tabs{display:flex;gap:12px;margin-bottom:26px}.admin-tabs [aria-pressed=true]{background:var(--soft);border-color:var(--accent)}.wide-dialog{width:min(720px,calc(100% - 28px));max-height:90dvh;overflow-y:auto}dialog{max-height:90dvh;overflow-y:auto}select{display:block;width:100%;border:1px solid var(--line);background:var(--surface);font:inherit;color:var(--ink);padding:13px;border-radius:6px;margin-top:9px}.form-row{display:grid;grid-template-columns:1fr 1fr;gap:20px}.check-label{display:flex;gap:12px;align-items:center;line-height:1.5}.check-label input{display:inline-block;width:20px;height:20px;margin:0;flex-shrink:0}.text-button:disabled{cursor:default}.small{line-height:1.6}#admin-link{margin-top:0}#show-previous{margin:20px 0 0;text-align:left;font-size:14px}#previous-note{margin-bottom:0}.brand{flex-shrink:0}.brand-note{white-space:nowrap}nav button{justify-content:space-between}.topline{flex-wrap:wrap}form .primary{min-height:44px}button{min-height:40px}input,select{font-size:16px}#task-message,#edit-comment-message{color:#79422e}
@media(max-width:1100px){.comparing{grid-template-columns:1fr}.brand-note{display:none}.layout{grid-template-columns:210px minmax(0,1fr)}}
@media(max-width:760px){.card-grid{grid-template-columns:1fr}.layout{grid-template-columns:175px minmax(0,1fr)}aside{padding:30px 12px}.section-heading{align-items:flex-start;flex-direction:column}.admin-row{align-items:flex-start;flex-wrap:wrap}.welcome{padding-top:8px}.welcome h1{font-size:38px}.header-actions #profile{max-width:160px}}
@media(max-width:640px){header{height:auto;min-height:80px;flex-wrap:wrap;padding:16px 20px;gap:12px}.header-actions{flex-wrap:wrap;max-width:100%}.header-actions #profile{max-width:180px}.layout{display:block}.home-link{margin:0 10px 12px;font-size:14px}aside{padding:16px 14px}.home-link,.history{min-height:36px}.welcome h1{font-size:36px}.card-grid{gap:12px}.category-card,.task-card{padding:22px}.comparing{gap:14px}.form-row{grid-template-columns:1fr;gap:0}.wide-dialog,dialog{padding:28px 22px}.admin-tabs{flex-wrap:wrap}.topline{font-size:12px}.topline>span:last-child{display:none}.paper-top,.paper-bottom{flex-wrap:wrap}.answer-text{padding:8px 16px 22px}.history{margin-top:4px;padding:10px}.aside-note{display:none}main{padding-top:20px}.welcome{margin-bottom:24px;padding-bottom:30px}.welcome .primary{width:100%}.small{font-size:13px}.task-card h2{font-size:25px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}button{transition:none}}
.welcome-story{max-width:800px;margin:24px 0 30px}.welcome-story p{font:20px/1.8 Georgia,serif;margin:0 0 18px}
.home-link[aria-current="page"]{color:var(--accent);font-weight:bold;text-decoration:underline;text-underline-offset:5px}
#textbook-panel{max-width:880px}.book-note{font-size:14px;line-height:1.75;color:var(--muted);margin:16px 0 24px}.book-contents{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0;border:1px solid var(--line);border-radius:8px;background:var(--surface);padding:12px;margin:26px 0 32px;overflow:visible}.book-contents a{display:block;padding:12px;color:var(--ink);font-size:14px;line-height:1.5;text-decoration:none;overflow-wrap:anywhere;border-radius:5px}.book-contents a:hover{background:var(--soft)}.book-chapters>details{border-top:1px solid var(--line);padding:8px 0;scroll-margin-top:24px}.book-chapters>details:last-child{border-bottom:1px solid var(--line)}.book-chapters summary{display:flex;align-items:center;gap:16px;padding:17px 4px;cursor:pointer;list-style:none}.book-chapters summary::-webkit-details-marker{display:none}.book-chapters summary::after{content:'+';font-size:24px;color:var(--muted);margin-left:auto}.book-chapters details[open]>summary::after{content:'−'}.book-chapters summary h2{font:normal 25px/1.35 Georgia,serif;margin:0}.lesson-number{font:italic 18px Georgia,serif;color:var(--muted);flex-shrink:0}.lesson-body{padding:0 0 22px 40px;font-size:16px;line-height:1.85}.lesson-body p{margin:0 0 18px}.lesson-body li{padding-left:4px;margin-bottom:12px}.lesson-body ol{padding-left:22px}.lesson-example{padding:20px 22px;border-left:3px solid #a3b99b;background:var(--surface);border-radius:0 8px 8px 0;margin:22px 0}.lesson-example b{display:block;font:600 12px/1.5 Arial,sans-serif;color:var(--muted);margin-bottom:7px}.lesson-example p{font:18px/1.75 Georgia,serif}.lesson-example p:last-child{margin:0}.lesson-drill{padding-top:4px}.lesson-practice{display:inline-block;padding:11px 16px;border:1px solid var(--line);border-radius:6px;color:var(--accent);font-size:14px;text-decoration:none}.lesson-practice:hover{background:var(--soft)}
@media(max-width:640px){.book-contents{grid-template-columns:1fr;margin:22px 0;display:grid}.book-chapters summary{gap:12px}.book-chapters summary h2{font-size:22px}.lesson-body{padding-left:0}.lesson-example{padding:16px}.lesson-practice{width:100%;text-align:center}.book-chapters>details{scroll-margin-top:12px}}
.catalog-filter{margin:4px 0 18px;cursor:pointer;font-size:16px}.completed-badge{display:inline-flex;align-self:flex-start;background:var(--soft);border:1px solid #adbea8;border-radius:18px;padding:6px 12px;color:#36583c;font-size:14px}.task-card.completed{border-color:#adbea8}.user-row{align-items:flex-start}.user-email{overflow-wrap:anywhere;font-size:14px;margin:8px 0}.user-actions,.dialog-actions{display:flex;flex-wrap:wrap;gap:10px}.user-actions{justify-content:flex-end}.danger{color:#873f37;border-color:#d9b7af}.danger:hover{background:#f5e9e5}#user-action-error{color:#873f37}.dialog-actions .primary{width:auto;flex:1}.admin-tabs{flex-wrap:wrap}@media(max-width:760px){.user-row{flex-direction:column}.user-actions{justify-content:flex-start}.user-actions button{min-height:44px}.catalog-filter{align-items:flex-start}}
.ai-review { margin: 12px 0 24px; }
.ai-review .answer-text { overflow-wrap: anywhere; line-height: 1.8; }
.ai-review .answer-text:not(:empty) { padding: 22px; border: 1px solid var(--line, #d8dfd6); border-radius: 8px; }
.pagination{display:flex;align-items:center;justify-content:center;gap:16px;flex-wrap:wrap;margin:24px 0}.lesson-body p{white-space:pre-wrap}.lesson-body h3{margin:24px 0 12px}#chapter-body{min-height:380px}.ai-summary{line-height:1.9}.form-error{color:#873f37}
.welcome-links{display:flex;flex-direction:column;align-items:flex-start;gap:12px}.welcome-links a{text-decoration:none;text-align:center}.topline #breadcrumb{display:inline}
.notification{padding:22px;margin:18px 0;border:1px solid var(--line);border-radius:8px;background:var(--surface)}.notification.unread{border-left:4px solid var(--accent);background:var(--soft)}.notification h2,.notification h3{overflow-wrap:anywhere}.message-body{white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.8}.message-form{max-width:700px;margin-bottom:36px}.message-form textarea{min-height:180px;border:1px solid var(--line);border-radius:6px;font:16px/1.7 Arial,sans-serif;padding:15px;margin-top:9px}.message-form label{display:block;margin:18px 0}#announcement-error,#announcement-send-error{color:#873f37}#inbox-button{white-space:nowrap}.notification summary{cursor:pointer}@media(max-width:640px){.notification{padding:16px}.header-actions{gap:8px}#announcement-preview .dialog-actions{flex-direction:column}}
.category-card,.task-card,.category-nav-link,.pagination a{color:var(--ink);text-decoration:none}.category-nav-link{display:flex;align-items:center;justify-content:space-between;gap:15px;padding:15px 14px;border-radius:7px;color:var(--muted)}.category-nav-link:hover{background:#e9efe5}.category-nav-link.active{background:var(--soft);color:var(--ink)}.pagination{margin-top:24px}#brief{white-space:pre-line}#exercise-chapter{margin:0 0 20px}.welcome h1{max-width:850px}#home-panel>.brief{max-width:800px}@media(max-width:640px){.category-nav-link{padding:10px;white-space:nowrap}.category-nav-link .nav-number{display:none}}

/* Keep reading and writing comfortable at intermediate screen sizes. */
textarea::placeholder{color:#697769}button:disabled{cursor:default}#exercise-chapter .small{font-size:14px}.actions{flex-wrap:wrap}.actions button{flex:1 1 150px}.brand{min-width:0}.brand-note{white-space:normal;max-width:400px}.header-actions{flex-shrink:0}
@media(max-width:1000px){.card-grid{grid-template-columns:1fr}}
@media(max-width:640px){.actions button{flex-basis:auto}.header-actions{flex-shrink:1}}

.difficulty-filter{display:block;max-width:320px;margin:16px 0;font-size:14px}.difficulty-filter select{margin-top:8px}#workspace .time{display:inline-block;white-space:normal;max-width:220px;flex-shrink:0}@media(max-width:900px){#workspace .heading{align-items:flex-start;flex-direction:column;gap:0}#workspace .time{margin:0 0 18px}}
/* Support conversations keep long messages readable on small screens. */
.support-form{margin:24px 0;max-width:720px}.support-form textarea{min-height:150px;resize:vertical}.support-filter{display:block;max-width:320px;margin:18px 0}.support-thread{display:grid;gap:14px;margin:24px 0}.support-message{border:1px solid var(--line);border-radius:12px;padding:18px;background:var(--surface);min-width:0}.support-answer{background:var(--soft);border-left:3px solid var(--accent)}.support-message p{margin:8px 0 0}.support-subject,.support-person,#support-content h3,#admin-support h3{overflow-wrap:anywhere}.support-form button{max-width:100%;white-space:normal}#support-content .section-heading,#admin-support .section-heading{flex-wrap:wrap;gap:12px}@media(max-width:600px){.support-message{padding:14px}.support-form textarea{min-height:140px}}
.support-form label{display:block;margin:18px 0}.support-form textarea{border:1px solid var(--line);background:var(--surface);border-radius:6px;font:16px/1.7 Arial,sans-serif;padding:15px;margin-top:9px}.support-form input{display:block;width:100%;border:1px solid var(--line);background:var(--surface);color:var(--ink);border-radius:6px;padding:13px;margin-top:9px}.support-form [role=status]{color:#873f37}
.example-flag{border-top:1px solid var(--line);margin-top:18px;padding-top:14px;display:flex;flex-wrap:wrap;align-items:center;gap:10px 18px}.example-flag .check-label{margin:0;cursor:pointer}.example-flag .small{margin:0}.example-flag.needs-change .check-label{font-weight:bold;color:#78553d}

.brand-name{white-space:nowrap}.brand .mark{flex-shrink:0}

/* Exercise navigation stays visible on desktop and folds on phones. */
.practice-menu>summary{font-size:12px;letter-spacing:1.7px;color:var(--muted);font-weight:600;text-transform:uppercase;list-style:none;cursor:default}
.practice-menu>summary::-webkit-details-marker{display:none}
footer{padding:12px 0}
footer a{display:inline-flex;align-items:center;min-height:44px;font-size:14px;color:var(--muted);text-decoration:none}
footer a:hover{color:var(--ink);text-decoration:underline;text-underline-offset:4px}
@media(max-width:640px){
  .site-links{display:flex;align-items:center;gap:16px;margin-bottom:12px}
  .site-links .home-link{margin:0;padding:8px;min-height:44px;display:flex;align-items:center}
  .practice-menu{border:1px solid var(--line);border-radius:8px;background:var(--surface)}
  .practice-menu>summary{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:48px;padding:14px 16px;font-size:16px;letter-spacing:0;text-transform:none;color:var(--ink);cursor:pointer}
  .practice-menu>summary::after{content:'';width:8px;height:8px;border-right:2px solid var(--muted);border-bottom:2px solid var(--muted);transform:rotate(45deg);flex-shrink:0;margin-right:3px;margin-top:-4px}
  .practice-menu[open]>summary::after{transform:rotate(225deg);margin-top:4px}
  .practice-menu[open]>summary{border-bottom:1px solid var(--line)}
  #categories{display:grid;gap:4px;overflow:visible;margin:0;padding:8px}
  #categories .category-nav-link{white-space:normal;overflow-wrap:anywhere;min-height:44px;padding:12px;line-height:1.4}
}