/* Messages: student <-> teacher chat (student/chat.html, teacher/chat.html). Tokens only. */

.chat-overview{margin-bottom:20px}
.chat{display:grid;grid-template-columns:340px minmax(0,1fr);height:var(--chat-h,640px);background:var(--sheet);border:1px solid var(--line);border-radius:var(--r-md);box-shadow:var(--sh-1);overflow:hidden}
.chat [hidden]{display:none!important}

/* ---------- conversation list ---------- */
.chat-list{display:flex;flex-direction:column;min-height:0;border-right:1px solid var(--line);background:var(--sheet)}
.chat-list-head{padding:16px 16px 12px;border-bottom:1px solid var(--line);display:flex;flex-direction:column;gap:10px}
.chat-list-head h2{font-size:var(--t-18)}
.chat-convos{list-style:none;margin:0;padding:6px;overflow-y:auto;flex:1;min-height:0;overscroll-behavior:contain}
.cv{display:flex;gap:12px;width:100%;text-align:left;padding:12px 10px;border:0;background:none;border-radius:10px;cursor:pointer;color:inherit;font:inherit;transition:background var(--dur) var(--ease)}
.cv:hover{background:var(--paper)}
.cv[aria-current="true"]{background:var(--accent-50)}
.cv .avatar,.ct-head .avatar{position:relative}
.avatar .on{position:absolute;right:-1px;bottom:-1px;width:12px;height:12px;border-radius:50%;background:var(--success);border:2px solid var(--sheet)}
.cv-chan{background:var(--brand-900);color:var(--on-brand)}
.cv-main{flex:1;min-width:0;display:flex;flex-direction:column;gap:2px}
.cv-top{display:flex;align-items:baseline;justify-content:space-between;gap:8px}
.cv-top b{font:600 var(--t-14)/1.3 var(--f-display);color:var(--brand-900);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.cv-top time{font-size:var(--t-12);color:var(--ink-3);font-variant-numeric:tabular-nums;flex:none}
.cv-prev{display:flex;align-items:center;gap:8px}
.cv-text{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:var(--t-14);color:var(--ink-2)}
.cv.has-unread .cv-text{color:var(--ink-1);font-weight:500}
.cv.has-unread .cv-top time{color:var(--brand-900);font-weight:600}
.cv-n{min-width:22px;height:22px;padding:0 6px;border-radius:var(--r-pill);background:var(--brand-900);color:var(--on-brand);font:700 var(--t-12)/22px var(--f-display);text-align:center;flex:none;font-variant-numeric:tabular-nums}
.cv-sub{font-size:var(--t-12);color:var(--ink-3);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.cv-typing{font-style:normal;color:var(--brand-700);font-weight:600}
.cv mark{background:var(--accent-100);color:inherit;border-radius:3px;padding:0 1px}
.pres{display:inline-flex;align-items:center;gap:5px}
.pres::before{content:"";width:7px;height:7px;border-radius:50%;border:1.5px solid var(--ink-3);flex:none}
.pres.on{color:var(--success);font-weight:600}
.pres.on::before{background:var(--success);border-color:var(--success)}
.chat-noresult{padding:28px 16px}
.chat-list-foot{border-top:1px solid var(--line);padding:12px 16px;display:flex;flex-direction:column;align-items:flex-start;gap:6px;background:var(--paper)}
.chat-demo{margin:0;display:flex;gap:8px;font-size:var(--t-12);color:var(--ink-2);line-height:1.45}
.chat-demo .ico-sm{flex:none;margin-top:1px;color:var(--brand-700)}
.chat-demo a{color:var(--brand-700)}
.chat-list-foot .btn{margin-left:-10px}

/* ---------- thread ---------- */
.chat-thread{display:flex;flex-direction:column;min-height:0;min-width:0;background:var(--paper)}
.ct{display:flex;flex-direction:column;height:100%;min-height:0}
.ct-head{display:flex;align-items:center;gap:12px;padding:12px 16px;background:var(--sheet);border-bottom:1px solid var(--line)}
.ct-back{display:none}
.ct-who{flex:1;min-width:0}
.ct-who h2{font-size:var(--t-18);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ct-who p{margin:2px 0 0;font-size:var(--t-12);color:var(--ink-2);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ct-hours-inline{display:none}
.ct-hours{display:inline-flex;align-items:center;gap:6px;height:28px;padding:0 10px;border-radius:var(--r-pill);background:var(--paper-2);color:var(--ink-2);font:600 var(--t-12)/1 var(--f-body);white-space:nowrap}
.ct-call{position:relative}
.ct-call .icon-btn[aria-disabled="true"]{opacity:.45;cursor:not-allowed}
.ct-call [role="tooltip"]{position:absolute;right:0;top:calc(100% + 6px);z-index:6;background:var(--brand-900);color:var(--on-brand);font-size:var(--t-12);padding:6px 10px;border-radius:8px;white-space:nowrap;opacity:0;transform:translateY(-3px);pointer-events:none;transition:opacity 140ms var(--ease),transform 140ms var(--ease);box-shadow:var(--sh-2)}
.ct-call:hover [role="tooltip"],.ct-call:focus-within [role="tooltip"]{opacity:1;transform:none}
.ct-safe{margin:0;display:flex;gap:8px;align-items:flex-start;padding:8px 16px;font-size:var(--t-12);line-height:1.45;color:var(--ink-2);background:var(--sheet);border-bottom:1px solid var(--line)}
.ct-safe .ico-sm{flex:none;color:var(--success);margin-top:1px}

.ct-body{position:relative;flex:1;min-height:0;display:flex}
.ct-log{flex:1;min-width:0;overflow-y:auto;overscroll-behavior:contain;padding:22px 20px 14px;display:flex;flex-direction:column;
  background-image:repeating-linear-gradient(to bottom,transparent 0 31px,rgba(var(--brand-rgb),.045) 31px 32px);background-attachment:local}
.ct-log:focus-visible{box-shadow:inset 0 0 0 2px var(--brand-900)}
.ct-day{align-self:center;margin:16px 0 6px}
.ct-day span{display:inline-block;font:600 var(--t-12)/1 var(--f-display);color:var(--ink-2);background:var(--sheet);border:1px solid var(--line);padding:6px 12px;border-radius:var(--r-pill)}
.ct-unread span{color:var(--accent-700);border-color:var(--accent-200);background:var(--accent-50)}
.ct-sys{align-self:center;display:flex;gap:6px;align-items:center;margin:8px 0 2px;max-width:92%;font-size:var(--t-12);color:var(--warn);background:var(--warn-bg);padding:6px 12px;border-radius:8px}

.msg{position:relative;display:flex;flex-direction:column;max-width:min(76%,560px);margin-top:12px;outline:none;touch-action:pan-y}
.msg.cont{margin-top:4px}
.msg.mine{align-self:flex-end;align-items:flex-end}
.msg.theirs{align-self:flex-start;align-items:flex-start}
.msg.in{animation:msg-in 240ms var(--ease) both}
@keyframes msg-in{from{opacity:0;transform:translateY(8px)}}
.msg-by{font:600 var(--t-12)/1.2 var(--f-display);color:var(--brand-700);margin:0 0 4px 4px}
.bubble{position:relative;max-width:100%;padding:9px 12px 6px;border-radius:14px;font-size:15px;line-height:1.5;overflow-wrap:anywhere;box-shadow:var(--sh-1);transition:transform 160ms var(--ease),box-shadow var(--dur) var(--ease)}
.by-teacher .bubble{background:var(--sheet);border:1px solid var(--line-2);color:var(--brand-900)}
.by-student .bubble{background:var(--brand-50);border:1px solid var(--brand-100);color:var(--ink-1)}
.msg.mine .bubble{border-bottom-right-radius:4px}
.msg.theirs .bubble{border-bottom-left-radius:4px}
.bubble .txt{margin:0}
.bubble em.pen{font-style:normal;font-weight:600;padding:0 1px;background:linear-gradient(transparent 80%,var(--accent-500) 80%,var(--accent-500) 92%,transparent 92%)}
.meta{display:flex;justify-content:flex-end;align-items:center;gap:4px;margin-top:3px;font-size:var(--t-12);color:var(--ink-3);font-variant-numeric:tabular-nums;line-height:1}
.rcpt{display:inline-flex;align-items:center;gap:3px;color:var(--ink-3)}
.rcpt .ico-sm{width:15px;height:15px}
.rcpt.read{color:var(--info)}
.rcpt-w{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.msg.last-mine .rcpt-w{position:static;width:auto;height:auto;clip:auto;font-weight:600}
.msg:focus-visible .bubble{box-shadow:var(--focus)}
.msg.flash .bubble{animation:flash 1.4s var(--ease)}
@keyframes flash{0%,45%{box-shadow:0 0 0 3px rgba(var(--accent-rgb),.5)}100%{box-shadow:var(--sh-1)}}
.msg.swipe-ready .bubble{box-shadow:0 0 0 2px var(--brand-700)}

.quote{display:block;width:100%;margin:0 0 6px;padding:6px 10px;border:0;border-radius:8px;background:rgba(var(--brand-rgb),.07);text-align:left;font:inherit;font-size:var(--t-14);line-height:1.4;color:var(--ink-2);cursor:pointer}
.quote:hover{background:rgba(var(--brand-rgb),.11)}
.quote b{display:block;font:600 var(--t-12)/1.3 var(--f-display);color:var(--brand-800)}
.quote span{display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.att-img{display:block;padding:0;margin:-3px -6px 6px;border:0;background:none;border-radius:10px;overflow:hidden;cursor:zoom-in}
.att-img img{display:block;max-width:min(260px,100%);height:auto;max-height:300px;object-fit:cover;border-radius:10px}
.att-gone{display:flex;align-items:center;gap:6px;margin-bottom:6px;padding:8px 10px;font-size:var(--t-14);color:var(--ink-2);background:var(--paper-2);border-radius:8px}

.msg-extra{display:flex;flex-wrap:wrap;gap:6px;margin-top:5px}
.msg-extra:empty{display:none}
.rx{display:inline-flex;align-items:center;gap:5px;height:28px;padding:0 10px;border-radius:var(--r-pill);border:1px solid var(--line-2);background:var(--sheet);font:600 var(--t-12)/1 var(--f-display);color:var(--ink-2);cursor:pointer;font-variant-numeric:tabular-nums}
.rx:hover{border-color:var(--brand-700)}
.rx[aria-pressed="true"]{background:var(--brand-50);border-color:var(--brand-700);color:var(--brand-900)}
.msg-badge{text-decoration:none}

.msg-tools{position:absolute;top:-20px;z-index:3;display:flex;gap:2px;padding:3px;background:var(--sheet);border:1px solid var(--line-2);border-radius:10px;box-shadow:var(--sh-2);opacity:0;pointer-events:none;transform:translateY(4px);transition:opacity 140ms var(--ease),transform 140ms var(--ease)}
.msg.mine .msg-tools{right:6px}
.msg.theirs .msg-tools{left:6px}
.msg:hover .msg-tools,.msg:focus-within .msg-tools{opacity:1;pointer-events:auto;transform:none}
.msg-tools button{display:inline-flex;align-items:center;gap:4px;height:32px;min-width:32px;justify-content:center;padding:0 7px;border:0;border-radius:7px;background:none;color:var(--ink-2);font:600 var(--t-12)/1 var(--f-display);cursor:pointer}
.msg-tools button:hover{background:var(--paper-2);color:var(--brand-900)}
.msg-tools button[aria-pressed="true"]{color:var(--accent-700)}

/* voice notes */
.vn{display:flex;align-items:center;gap:10px;min-width:210px;padding:2px 0}
.vn-btn{width:36px;height:36px;flex:none;display:grid;place-items:center;border:0;border-radius:50%;background:var(--brand-900);color:var(--on-brand);cursor:pointer}
.vn-btn:hover{background:var(--brand-800)}
.vn-bars{flex:1;display:flex;align-items:center;gap:2px;height:28px}
.vn-bars i{flex:1;min-width:2px;max-width:4px;border-radius:2px;background:var(--d2);transition:background 120ms linear}
.vn-bars i.on{background:var(--brand-900)}
.vn-t{font:600 var(--t-12)/1 var(--f-display);color:var(--ink-2);font-variant-numeric:tabular-nums;min-width:30px}

.ct-jump{position:absolute;bottom:12px;left:50%;transform:translateX(-50%);box-shadow:var(--sh-2)}
.ct-typing{margin:0;display:flex;align-items:center;gap:8px;padding:4px 20px 8px;font-size:var(--t-12);color:var(--ink-2);background:var(--paper)}
.ct-typing .dots{display:inline-flex;gap:3px;padding:6px 8px;background:var(--sheet);border:1px solid var(--line-2);border-radius:10px}
.ct-typing .dots i{width:6px;height:6px;border-radius:50%;background:var(--brand-700);animation:dot 1.1s infinite ease-in-out}
.ct-typing .dots i:nth-child(2){animation-delay:.15s}.ct-typing .dots i:nth-child(3){animation-delay:.3s}
@keyframes dot{0%,80%,100%{opacity:.3;transform:none}40%{opacity:1;transform:translateY(-3px)}}

.ct-empty{margin:auto;max-width:380px;padding:24px;display:flex;flex-direction:column;align-items:center;gap:8px;text-align:center;color:var(--ink-2)}
.ct-empty>.ico{width:24px;height:24px;padding:16px;box-sizing:content-box;border-radius:16px;background:var(--paper-2);color:var(--brand-700)}
.ct-empty h3{font-size:var(--t-16);color:var(--brand-900)}
.ct-empty p{margin:0;font-size:var(--t-14)}
.ct-pick-wrap{flex:1;min-height:0;overflow-y:auto;padding:24px 16px;display:flex;flex-direction:column;align-items:center}
.ct-pick-wrap .ct-empty{margin:0 auto}
.chat-pick{list-style:none;margin:12px 0 0;padding:0;width:min(460px,100%);display:flex;flex-direction:column;gap:8px}
.pick{width:100%;display:flex;align-items:center;gap:12px;padding:12px 14px;background:var(--sheet);border:1px solid var(--line-2);border-radius:var(--r-md);text-align:left;font:inherit;color:inherit;cursor:pointer;transition:border-color var(--dur) var(--ease)}
.pick:hover{border-color:var(--brand-700)}
.pick .end{margin-left:auto;display:inline-flex;align-items:center;gap:4px;font:600 var(--t-12)/1 var(--f-display);color:var(--brand-700);white-space:nowrap}

/* composer */
.ct-foot{display:flex;flex-direction:column;gap:8px;padding:10px 14px 10px;background:var(--sheet);border-top:1px solid var(--line)}
.ct-ooh{margin:0;display:flex;align-items:center;gap:8px;padding:6px 10px;border-radius:8px;font-size:var(--t-12);color:var(--warn);background:var(--warn-bg)}
.ct-quick{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none;margin:0 -2px;padding:2px}
.ct-quick::-webkit-scrollbar{display:none}
.ct-quick .chip{height:32px;font-size:13px;white-space:nowrap;flex:none}
.ct-quick .chip:hover{border-color:var(--brand-700)}
.ct-replying,.ct-pending{display:flex;align-items:center;gap:10px;padding:6px 6px 6px 12px;background:var(--paper);border:1px solid var(--line);border-radius:10px}
.ct-replying>.ico-sm{color:var(--brand-700);flex:none}
.rp-txt,.pd-txt{flex:1;min-width:0;display:flex;flex-direction:column;font-size:var(--t-12);line-height:1.35}
.rp-txt b,.pd-txt b{font:600 var(--t-12)/1.3 var(--f-display);color:var(--brand-800);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.rp-txt span,.pd-txt small{color:var(--ink-2);overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:var(--t-12)}
.ct-pending img{width:48px;height:48px;object-fit:cover;border-radius:6px;flex:none}
.ct-pending .vn{min-width:180px;flex:none}
.composer{display:flex;align-items:flex-end;gap:6px}
.composer>.icon-btn{width:44px;height:44px;flex:none}
.composer>.icon-btn[aria-pressed="true"]{background:var(--danger-bg);color:var(--danger)}
.cmp-field{position:relative;flex:1;min-width:0}
.cmp-field textarea{display:block;width:100%;min-height:44px;max-height:168px;resize:none;padding:11px 14px;border:1px solid var(--border-input);border-radius:12px;background:var(--sheet);color:var(--ink-1);font:inherit;font-size:15px;line-height:1.4;transition:border-color var(--dur) var(--ease),box-shadow var(--dur) var(--ease)}
.cmp-field textarea::placeholder{color:var(--ink-3)}
.cmp-field textarea:focus{outline:none;border-color:var(--brand-900);box-shadow:0 0 0 3px rgba(var(--brand-rgb),.12)}
.composer.recording textarea{visibility:hidden}
.cmp-rec{position:absolute;inset:0;display:flex;align-items:center;gap:10px;padding:0 4px 0 14px;border:1px solid var(--danger);border-radius:12px;background:var(--sheet);font-size:var(--t-14);color:var(--ink-1)}
.cmp-rec time{font:600 var(--t-14)/1 var(--f-display);font-variant-numeric:tabular-nums}
.rec-dot{width:10px;height:10px;border-radius:50%;background:var(--danger);animation:rec 1s infinite}
@keyframes rec{50%{opacity:.25}}
.rec-level{flex:1;min-width:0;display:flex;align-items:center;justify-content:flex-end;gap:2px;height:24px;overflow:hidden}
.rec-level i{width:3px;flex:none;border-radius:2px;background:var(--danger)}
.ct-send{flex:none}
.ct-keys{margin:-2px 0 0;font-size:var(--t-12);color:var(--ink-3)}
.ct-readonly p{margin:0;display:flex;align-items:center;gap:8px;font-size:var(--t-14);color:var(--ink-2)}
.ct-readonly .ico-sm{flex:none;color:var(--brand-700)}
.linkish{padding:0;border:0;background:none;font:inherit;color:var(--brand-700);text-decoration:underline;text-underline-offset:2px;cursor:pointer}

.chat-photo-dlg{width:min(900px,calc(100vw - 32px))}
.chat-photo-dlg img{display:block;max-width:100%;max-height:75vh;margin:0 auto;border-radius:8px}

/* ---------- tablets: no rail, tab bar at the bottom ---------- */
@media (max-width:1100px) and (min-width:761px){
  .chat{grid-template-columns:290px minmax(0,1fr)}
  .ct-hours{display:none}
  .ct-hours-inline{display:inline}
}

/* ---------- phones: list and thread are two screens ---------- */
@media (max-width:760px){
  .chat{display:block;height:auto;background:none;border:0;border-radius:0;box-shadow:none;overflow:visible}
  .chat-list{border:1px solid var(--line);border-radius:var(--r-md);box-shadow:var(--sh-1);overflow:hidden}
  .chat-convos{overflow:visible}
  .cv{min-height:72px}
  .chat[data-view="list"] .chat-thread{display:none}
  .chat:not([data-view="list"]) .chat-thread{position:fixed;left:0;right:0;top:0;bottom:var(--tb,0px);z-index:35;padding-top:env(safe-area-inset-top)}
  .chat.kb-open:not([data-view="list"]) .chat-thread{bottom:var(--kb,0px)}
  html.chat-locked,html.chat-locked body{overflow:hidden}
  .content:has(.chat:not([data-view="list"])){animation:none}
  .ct-back{display:inline-grid;margin-left:-8px}
  .ct-head{gap:10px;padding:8px 12px}
  .ct-head .avatar{--sz:34px}
  .ct-who h2{font-size:var(--t-16)}
  .ct-hours{display:none}
  .ct-hours-inline{display:inline}
  .ct-safe{padding:6px 12px}
  .ct-log{padding:20px 12px 12px}
  .msg{max-width:86%}
  .ct-foot{padding:8px 10px}
  .composer{gap:4px}
  .composer>.icon-btn{width:40px}
  .ct-send{width:44px;padding:0}
  .ct-send span{display:none}
  .ct-keys{display:none}
  .ct-typing{padding:4px 12px 8px}
}
@media (max-width:760px){
  .ct-who p{white-space:normal;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical}
}

/* ---- full-screen messenger layout (no page heading; list + thread fill the window) ---- */
.content:has(> .chat){padding:0;max-width:none}
.chat{height:calc(100dvh - var(--chat-top,94px));border:0;border-radius:0;box-shadow:none;grid-template-columns:minmax(300px,380px) minmax(0,1fr)}
.chat-list-head{padding:14px 14px 10px;gap:10px}
.chat-list-top{display:flex;align-items:center;justify-content:space-between;gap:8px}
.chat-title{font:700 var(--t-24)/1.1 var(--f-display);color:var(--brand-900);margin:0}
.chat-list-foot{padding:8px 14px}
.chat-demo{font-size:11.5px}
.ct-log{background:var(--paper) repeating-linear-gradient(180deg,transparent 0 31px,rgba(var(--brand-rgb),.035) 31px 32px)}
.msg{max-width:min(68%,640px)}
.bubble{font-size:15.5px}
@media (min-width:1400px){.chat{grid-template-columns:400px minmax(0,1fr)}}
@media (max-width:760px){
  .chat{height:auto}
  .chat-list{border:0;border-radius:0;box-shadow:none;min-height:calc(100dvh - var(--chat-top,94px) - 64px)}
  .chat-list-head{background:var(--sheet);border-bottom:1px solid var(--line)}
  .msg{max-width:84%}
}
/* inside a conversation on phones the app's bottom menu steps aside, like a messaging app */
@media (max-width:760px){
  body:has(.chat:not([data-view="list"])) .tabbar{display:none}
  .chat:not([data-view="list"]) .chat-thread{bottom:0}
  .chat.kb-open:not([data-view="list"]) .chat-thread{bottom:var(--kb,0px)}
}
/* desktop: only the message list scrolls, never the page */
@media (min-width:761px){
  html:has(.content > .chat){overflow:hidden}
}