/* Global Tutor Board — shared design system (REVAMP_SPEC §3.5)
   Single source of truth for student.html (board), tutor.html (board), profile.html (detail).
   Self-hosted (no CDN) to preserve China-reachability. */
:root{
  --bg:#f6f9f9; --surface:#ffffff; --ink:#0f2a2e; --muted:#5b7075; --line:#e4ecec;
  --accent:#12b3a6; --accent-dark:#0d8f85; --accent-soft:#e6f7f5;
  --amber:#f5a623; --radius:20px; --shadow:0 6px 24px rgba(15,42,46,.07);
  --shadow-hover:0 12px 34px rgba(15,42,46,.13);
  --nav-h:64px; --tab-h:64px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,"PingFang SC","Microsoft YaHei",sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html{-webkit-text-size-adjust:100%}
body{font-family:var(--font);background:var(--bg);color:var(--ink);line-height:1.5;
     padding-bottom:calc(var(--tab-h) + env(safe-area-inset-bottom));-webkit-font-smoothing:antialiased}
@media(min-width:761px){body{padding-bottom:0}}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}

/* ---------- top nav (desktop) ---------- */
.topnav{position:sticky;top:0;z-index:50;height:var(--nav-h);background:rgba(255,255,255,.9);
        backdrop-filter:saturate(140%) blur(10px);border-bottom:1px solid var(--line);
        display:flex;align-items:center;gap:20px;padding:0 clamp(16px,4vw,40px)}
.brand{display:flex;align-items:center;gap:9px;font-weight:800;font-size:18px;letter-spacing:-.02em}
.brand .dot{width:26px;height:26px;border-radius:8px;background:linear-gradient(135deg,var(--accent),var(--accent-dark));
            display:grid;place-items:center;color:#fff;font-size:15px}
.topnav .spacer{flex:1}
.topnav .navlink{font-weight:600;color:var(--muted);font-size:14px;padding:8px 6px;border-radius:8px}
.topnav .navlink:hover,.topnav .navlink.active{color:var(--ink)}
.topnav .cta{background:var(--accent);color:#fff;padding:9px 16px;border-radius:12px;font-weight:700;font-size:14px}
.topnav .cta:hover{background:var(--accent-dark)}
.lang-select{border:1px solid var(--line);background:var(--surface);border-radius:10px;padding:7px 9px;
             font-family:inherit;font-size:13px;color:var(--muted);cursor:pointer}

/* ---------- layout / hero ---------- */
.wrap{max-width:1180px;margin:0 auto;padding:0 clamp(16px,4vw,40px)}
.hero{padding:28px 0 8px}
.eyebrow{display:inline-flex;align-items:center;gap:7px;background:var(--accent-soft);color:var(--accent-dark);
         font-weight:700;font-size:12.5px;padding:6px 12px;border-radius:999px;margin-bottom:14px}
.hero h1{font-size:clamp(26px,5vw,40px);line-height:1.1;letter-spacing:-.03em;font-weight:800}
.hero h1 .accent{color:var(--accent)}
.hero p{color:var(--muted);margin-top:10px;font-size:15px;max-width:560px}
.searchbar{margin:20px 0 6px;position:relative;max-width:560px}
.searchbar input{width:100%;border:1px solid var(--line);background:var(--surface);border-radius:14px;
                 padding:14px 16px 14px 44px;font-family:inherit;font-size:15px;color:var(--ink);box-shadow:var(--shadow)}
.searchbar input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 4px var(--accent-soft)}
.searchbar svg{position:absolute;left:15px;top:50%;transform:translateY(-50%);width:19px;height:19px;stroke:var(--muted);fill:none}

/* ---------- filter chips ---------- */
.chips{display:flex;gap:9px;overflow-x:auto;padding:16px 0 6px;-webkit-overflow-scrolling:touch;scrollbar-width:none}
.chips::-webkit-scrollbar{display:none}
.chip{flex:0 0 auto;border:1px solid var(--line);background:var(--surface);color:var(--muted);
      font-weight:600;font-size:13.5px;padding:8px 15px;border-radius:999px;cursor:pointer;white-space:nowrap;transition:.15s;text-transform:capitalize}
.chip:hover{border-color:var(--accent);color:var(--accent-dark)}
.chip.active{background:var(--accent);border-color:var(--accent);color:#fff}
/* curated filter dropdowns (Languages / Subjects) */
.fdrop{position:relative;flex:0 0 auto}
.chip.hasmenu{display:inline-flex;align-items:center;gap:4px}
/* position:fixed so the menu escapes the .chips overflow-x:auto clip (positioned by JS) */
.fmenu{display:none;position:fixed;z-index:80;background:var(--surface);
       border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow-hover);padding:6px;min-width:190px;max-height:320px;overflow-y:auto}
.fmenu.open{display:block}
.fmenu button{display:block;width:100%;text-align:left;background:none;border:none;font-family:inherit;font-size:13.5px;
              color:var(--ink);padding:9px 12px;border-radius:9px;cursor:pointer;white-space:nowrap}
.fmenu button:hover{background:var(--accent-soft);color:var(--accent-dark)}
.fmenu button.on{background:var(--accent);color:#fff}

.toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-top:4px}
.count{color:var(--muted);font-size:13.5px;font-weight:600}
.sortbtn{border:1px solid var(--line);background:var(--surface);color:var(--muted);font-weight:600;font-size:13px;
         padding:8px 13px;border-radius:10px;cursor:pointer;font-family:inherit}
.sortbtn.active{color:var(--accent-dark);border-color:var(--accent)}

/* ---------- board grid + cards ---------- */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:20px;padding:20px 0 40px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;
      cursor:pointer;box-shadow:var(--shadow);transition:transform .18s,box-shadow .18s;display:flex;flex-direction:column}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow-hover)}
.photo{position:relative;aspect-ratio:4/5;background:var(--accent-soft);overflow:hidden}
.photo img{width:100%;height:100%;object-fit:cover}
.ribbon{position:absolute;top:12px;left:12px;background:var(--amber);color:#3a2600;font-weight:800;font-size:11px;
        letter-spacing:.04em;padding:5px 10px;border-radius:999px;box-shadow:0 2px 8px rgba(0,0,0,.15)}
.vid{position:absolute;top:12px;right:12px;background:rgba(15,42,46,.72);color:#fff;font-weight:700;font-size:10.5px;
     padding:5px 9px;border-radius:999px;display:flex;align-items:center;gap:5px;backdrop-filter:blur(4px)}
.vid::before{content:"";border-style:solid;border-width:5px 0 5px 8px;border-color:transparent transparent transparent #fff}
.cbody{padding:14px 15px 16px;display:flex;flex-direction:column;gap:9px;flex:1}
.namerow{display:flex;align-items:center;gap:8px}
.flag{font-size:18px;line-height:1;flex:0 0 auto}
.namerow h3{font-size:16.5px;font-weight:800;letter-spacing:-.01em;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.badge{display:inline-flex;align-items:center;gap:4px;font-size:11px;font-weight:700;padding:3px 8px;border-radius:999px;flex:0 0 auto}
.badge.ok{background:var(--accent-soft);color:var(--accent-dark)}
.badge.new{background:#fff4e0;color:#a86400}
.pills{display:flex;flex-wrap:wrap;gap:6px}
.pill{background:var(--bg);border:1px solid var(--line);color:var(--muted);font-size:11.5px;font-weight:600;
      padding:3px 9px;border-radius:8px;text-transform:capitalize}
.cfoot{display:flex;align-items:center;justify-content:space-between;margin-top:auto;padding-top:6px}
.rate{font-weight:800;font-size:16px}.rate small{color:var(--muted);font-weight:600;font-size:12px}
.view{color:var(--accent-dark);font-weight:700;font-size:13px;display:flex;align-items:center;gap:3px}
.empty{grid-column:1/-1;text-align:center;padding:60px 20px;color:var(--muted)}
.empty button{background:none;border:none;color:var(--accent-dark);font-weight:700;cursor:pointer;text-decoration:underline;font-family:inherit;font-size:inherit}
.loading{text-align:center;padding:70px 20px;color:var(--muted)}

/* ---------- 2-up on mobile (single source; both boards) ---------- */
@media(max-width:760px){
  .topnav .navlink,.topnav .cta{display:none}
  .grid{grid-template-columns:1fr 1fr;gap:12px}
  .namerow h3{font-size:15px}
  .cbody{padding:12px 12px 14px;gap:7px}
  .rate{font-size:15px}
}

/* ---------- bottom tab bar (mobile) ---------- */
.tabbar{display:none}
@media(max-width:760px){
  .tabbar{display:flex;position:fixed;left:0;right:0;bottom:0;z-index:60;height:calc(var(--tab-h) + env(safe-area-inset-bottom));
          padding-bottom:env(safe-area-inset-bottom);background:rgba(255,255,255,.94);backdrop-filter:blur(10px);border-top:1px solid var(--line)}
  .tab{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px;
       color:var(--muted);font-size:11px;font-weight:600;cursor:pointer;background:none;border:none;font-family:inherit}
  .tab svg{width:23px;height:23px;stroke:var(--muted);fill:none}
  .tab.active{color:var(--accent-dark)}.tab.active svg{stroke:var(--accent-dark)}
}

/* ---------- profile detail page ---------- */
.pback{display:inline-flex;align-items:center;gap:6px;color:var(--muted);font-weight:600;font-size:14px;padding:20px 0 4px}
.pback:hover{color:var(--ink)}
.profile{display:grid;grid-template-columns:340px 1fr;gap:28px;padding:8px 0 40px;align-items:start}
/* grid items default to min-width:auto; without this the 460px availability calendar
   can't shrink and inflates the layout viewport (page renders "too big" on mobile). */
.profile>*{min-width:0}
@media(max-width:820px){.profile{grid-template-columns:1fr;gap:20px}}
.pphoto{position:relative;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);background:var(--accent-soft);aspect-ratio:4/5;position:sticky;top:84px}
@media(max-width:820px){.pphoto{position:relative;top:0;max-width:360px;margin:0 auto}}
.pphoto img{width:100%;height:100%;object-fit:cover}
.pname{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.pname h1{font-size:clamp(24px,4vw,32px);font-weight:800;letter-spacing:-.02em}
.porigin{color:var(--muted);font-size:15px;margin-top:4px}
.prates{display:flex;gap:12px;margin:18px 0}
.ratebox{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:12px 18px;box-shadow:var(--shadow)}
.ratebox small{display:block;color:var(--muted);font-size:11.5px;font-weight:700;text-transform:uppercase;letter-spacing:.04em}
.ratebox span{font-size:22px;font-weight:800}
.psec{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:20px;margin-bottom:18px;box-shadow:var(--shadow)}
.psec h2{font-size:14px;font-weight:800;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);margin-bottom:12px}
.psec p{font-size:14.5px;line-height:1.7;color:var(--ink);white-space:pre-line}
.msgbtn{width:100%;background:var(--accent);color:#fff;border:none;border-radius:14px;padding:15px;font-weight:800;font-size:16px;cursor:pointer;font-family:inherit;box-shadow:var(--shadow)}
.msgbtn:hover{background:var(--accent-dark)}
.msgnote{text-align:center;color:var(--muted);font-size:12px;margin-top:9px}
.pvideo{border-radius:14px;overflow:hidden;border:1px solid var(--line);aspect-ratio:16/9;background:#000;max-width:100%}
.pvideo iframe,.pvideo video{width:100%;height:100%;max-width:100%;object-fit:contain;border:0;display:block}

/* availability calendar (empty-state until data exists) */
.cal{overflow-x:auto;max-width:100%}
.calgrid{display:grid;grid-template-columns:70px repeat(7,minmax(52px,1fr));gap:6px;min-width:460px}
.calgrid .h{font-size:11px;font-weight:800;color:var(--muted);text-align:center;padding:6px 0;text-transform:uppercase;letter-spacing:.03em}
.calgrid .rl{font-size:11px;font-weight:700;color:var(--muted);display:flex;align-items:center}
.calgrid .slot{background:var(--bg);border:1px solid var(--line);border-radius:8px;height:34px;display:grid;place-items:center;color:#b8c6c6;font-size:13px}
.cal-empty{margin-top:12px;background:var(--accent-soft);color:var(--accent-dark);border-radius:12px;padding:12px 14px;font-size:13px;font-weight:600;text-align:center}

/* ---------- shared: request modal + wechat fab ---------- */
.overlay{display:none;position:fixed;inset:0;background:rgba(15,42,46,.5);z-index:100;align-items:center;justify-content:center;padding:16px}
.overlay.open{display:flex}
.sheet{background:var(--surface);border-radius:22px;max-width:440px;width:100%;max-height:90vh;overflow-y:auto;padding:24px;box-shadow:0 24px 60px rgba(0,0,0,.3)}
.sheet h2{font-size:20px;font-weight:800;margin-bottom:4px}
.sheet p.sub{color:var(--muted);font-size:13.5px;margin-bottom:16px}
.sheet label{font-size:12.5px;font-weight:700;color:var(--muted);display:block;margin:12px 0 5px}
.sheet input,.sheet textarea{width:100%;border:1px solid var(--line);border-radius:11px;padding:11px 12px;font-family:inherit;font-size:14px}
.sheet input:focus,.sheet textarea:focus{outline:none;border-color:var(--accent)}
.sheet .primary{width:100%;background:var(--accent);color:#fff;border:none;border-radius:12px;padding:13px;font-weight:800;font-size:15px;cursor:pointer;margin-top:18px;font-family:inherit}
.sheet .primary:hover{background:var(--accent-dark)}
.sheet .x{float:right;background:none;border:none;font-size:24px;color:var(--muted);cursor:pointer;line-height:1}
#wechat-fab{position:fixed;bottom:calc(var(--tab-h) + 18px);right:18px;width:54px;height:54px;background:#07C160;border-radius:50%;
            display:flex;align-items:center;justify-content:center;cursor:pointer;z-index:70;box-shadow:0 4px 18px rgba(7,193,96,.45);border:none}
@media(min-width:761px){#wechat-fab{bottom:22px}}
#wechat-fab svg{width:29px;height:29px;fill:#fff}
#wechat-popup{display:none;position:fixed;bottom:calc(var(--tab-h) + 80px);right:18px;background:#fff;border:1px solid rgba(7,193,96,.35);
              border-radius:18px;padding:18px;z-index:69;box-shadow:0 12px 40px rgba(15,42,46,.18);text-align:center;width:190px}
@media(min-width:761px){#wechat-popup{bottom:86px}}
#wechat-popup.open{display:block}
#wechat-popup img{width:144px;height:144px;border-radius:10px;border:2px solid rgba(7,193,96,.4);margin:0 auto 9px}
#wechat-popup strong{display:block;color:#07C160;font-size:13px;font-weight:800;margin-bottom:5px}
#wechat-popup p{margin:0;font-size:11px;color:var(--muted);line-height:1.4}