:root{--bg:#F5F1E8;--ink:#1B2033;--muted:#5B6272;--blue:#2540C8;--blue-l:#E3E8FB;--green:#17693F;--green-l:#DDF1E5;--red:#A8321F;--red-l:#F8E1DC;--line:#DDD7C8;--line2:#ECE7DA}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font-family:'IBM Plex Sans',sans-serif;font-size:16px;line-height:1.45}
a{color:var(--blue)}a:hover{color:#1A2E94}
h1,h2{font-family:'Bricolage Grotesque',sans-serif;font-weight:800;margin:0;line-height:1.1}
h1{font-size:40px}h2{font-size:22px}
.mono{font-family:'IBM Plex Mono',monospace;font-weight:600}
.muted{color:var(--muted)}
header.top{height:64px;display:flex;align-items:center;justify-content:space-between;padding:0 40px;background:#fff;border-bottom:1px solid var(--line)}
.logo{font-family:'Bricolage Grotesque',sans-serif;font-weight:800;font-size:22px;color:var(--ink);text-decoration:none}
.topnav{display:flex;gap:28px;font-size:15px;font-weight:500;align-items:center}
.topnav a{color:var(--ink);text-decoration:none;padding:21px 0 19px;border-bottom:2px solid transparent}
.topnav a.on{color:var(--blue);border-bottom-color:var(--blue)}
.chip{color:var(--blue)!important;font-weight:600;background:var(--blue-l);border-radius:999px;padding:8px 16px!important;border-bottom:0!important;text-decoration:none}
.chip.on{background:var(--blue);color:#fff!important}
.mobile-only{display:none}
.btn-quit{font-size:15px;font-weight:500;color:var(--ink);text-decoration:none;border:1.5px solid var(--line);border-radius:10px;padding:9px 16px}
.tabbar{display:none}
main{max-width:1100px;margin:0 auto;padding:32px 40px 60px;display:flex;flex-direction:column;gap:24px}
.sub{margin:8px 0 0;font-size:17px;color:var(--muted)}
.card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:26px 28px}
.row{display:flex;gap:24px;align-items:flex-start}
.row>.grow{flex:1.6}.row>.side{flex:1}
.grid{display:grid;gap:12px}
.btn{display:inline-block;text-align:center;text-decoration:none;cursor:pointer;font-family:inherit;font-weight:600;font-size:16px;border-radius:12px;padding:13px 28px;border:1.5px solid var(--blue);background:var(--blue);color:#fff;min-height:48px}
.btn.sec{background:#fff;color:var(--blue)}
.btn.ghost{background:#fff;color:var(--ink);border-color:var(--line)}
.btn.danger{background:#fff;color:var(--red);border-color:var(--line)}
.btn.block{display:block;width:100%}
.btn:disabled{opacity:.5;cursor:default}
.pick{position:relative}
.pick input{position:absolute;opacity:0;inset:0;cursor:pointer;margin:0}
.pick span{display:block;text-align:left;border-radius:12px;padding:12px 14px;min-height:46px;border:1.5px solid var(--line);background:#fff}
.pick input:checked+span{border:2px solid var(--blue);background:var(--blue-l)}
.pick input:focus-visible+span{outline:3px solid #9fb0f0}
.pick b{display:block;font-size:15px}.pick small{display:block;color:var(--muted);font-size:13px;margin-top:2px;line-height:1.35}
.num span{text-align:center;font-family:'IBM Plex Mono',monospace;font-weight:600;font-size:18px;min-width:72px}
.num input:checked+span{background:var(--blue);color:#fff;border-color:var(--blue)}
.num input:disabled+span{opacity:.45}
.flex{display:flex;gap:10px;flex-wrap:wrap}
label.lab{display:block;font-weight:600;font-size:14px;margin-bottom:6px}
input[type=text],input[type=password],input[type=email],select{width:100%;font-family:inherit;font-size:17px;padding:12px 16px;border-radius:10px;border:1.5px solid var(--line);background:#fff;color:var(--ink)}
input[type=checkbox]{width:22px;height:22px;accent-color:var(--blue);margin:0}
table.t{width:100%;border-collapse:collapse}
table.t th{text-align:left;font-size:13px;font-weight:600;letter-spacing:.05em;text-transform:uppercase;color:var(--muted);padding:10px 8px;border-bottom:2px solid var(--ink)}
table.t td{padding:12px 8px;border-bottom:1px solid var(--line2);font-size:16px;vertical-align:middle}
.pill{display:inline-block;font-weight:600;font-size:15px;border-radius:999px;padding:5px 14px}
.pill.g{background:var(--green-l);color:var(--green)}.pill.r{background:var(--red-l);color:var(--red)}.pill.b{background:var(--blue-l);color:var(--blue)}
.flash{padding:12px 18px;border-radius:12px;font-weight:600}
.flash.ok{background:var(--green-l);color:var(--green)}.flash.err{background:var(--red-l);color:var(--red)}
.bar{height:10px;border-radius:999px;background:#E4DECF;overflow:hidden}.bar>i{display:block;height:100%;background:var(--blue);border-radius:999px;transition:width .3s}
/* quiz */
.q-head{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}
.q-card{background:#fff;border:1px solid var(--line);border-radius:20px;padding:36px 40px 32px;display:flex;flex-direction:column;align-items:center;gap:26px}
.q-prompt{text-align:center}.q-prompt .w{font-family:'Bricolage Grotesque',sans-serif;font-weight:800;font-size:64px;line-height:1.1;margin-top:6px;overflow-wrap:anywhere}
.listen{margin-top:12px;cursor:pointer;display:inline-flex;align-items:center;gap:8px;font-family:inherit;font-weight:600;font-size:16px;color:var(--blue);background:var(--blue-l);border:none;border-radius:999px;padding:0 22px;min-height:48px}
.listen.big{color:#fff;background:var(--blue);font-size:20px;min-height:68px;padding:0 36px}
.listen.out{background:#fff;border:1.5px solid var(--blue);border-radius:10px;margin:0;min-height:44px}
.opts{width:100%;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.opt{cursor:pointer;font-family:'IBM Plex Mono',monospace;font-weight:600;font-size:24px;min-height:64px;border-radius:12px;color:#1B2033;background:#fff;border:1.5px solid var(--line);padding:6px 10px;overflow-wrap:anywhere}
.opt:hover:not(:disabled){border-color:var(--blue)}
.opt.sel{background:var(--blue-l);color:var(--blue);border:2px solid var(--blue)}
.val-row{width:100%;display:flex;align-items:center;justify-content:space-between;gap:16px;font-size:15px}
.opt.good{background:var(--green-l);color:var(--green);border:2px solid var(--green)}
.opt.bad{background:var(--red-l);color:var(--red);border:2px solid var(--red)}
.opt:disabled:not(.good):not(.bad){color:#7A8090;cursor:default}
.fb{width:100%;border-radius:12px;padding:16px 20px;display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap}
.fb.ok{background:var(--green-l)}.fb.ok .t{color:var(--green)}
.fb.no{background:var(--blue-l)}.fb.no .s{color:var(--blue)}
.fb .t{font-weight:600;font-size:17px}.fb .s{font-size:15px;margin-top:4px}.fb .l{font-family:'IBM Plex Mono',monospace;font-size:15px;margin-top:4px}
.fb .acts{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.write-in{width:100%;max-width:520px;font-family:'IBM Plex Mono',monospace;font-weight:600;font-size:26px;text-align:center}
.big-time{font-family:'IBM Plex Mono',monospace;font-weight:600;font-size:34px;color:var(--red)}
.bar.red>i{background:var(--red)}
.h-actions{display:flex;flex-direction:column;gap:10px}
.dir-cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.dir-cards a{display:block;text-decoration:none;color:var(--ink);background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 20px;font-weight:600}
.dir-cards a small{display:block;font-weight:400;color:var(--muted);margin-top:4px}
.dir-cards a:hover{border-color:var(--blue)}
.vrow{display:grid;grid-template-columns:44px 1fr 1fr 1.1fr 1.1fr;gap:12px;align-items:center;min-height:46px;border-bottom:1px solid var(--line2);font-size:15px}
.scroll{max-height:520px;overflow:auto}
@media (max-width:760px){
  h1{font-size:28px}h2{font-size:19px}
  header.top{height:56px;padding:0 16px}.logo{font-size:16px}
  .topnav{display:none}.mobile-only{display:inline-block}
  .chip{font-size:14px;padding:8px 14px!important}
  main{padding:16px 16px 28px;gap:16px}
  body.has-tabs{padding-bottom:64px}
  .tabbar{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));position:fixed;left:0;right:0;bottom:0;height:64px;background:#fff;border-top:1px solid var(--line);z-index:5}
  .tabbar a{display:flex;align-items:center;justify-content:center;text-decoration:none;font-size:13px;font-weight:600;color:var(--muted);border-top:3px solid transparent}
  .tabbar a.on{color:var(--blue);border-top-color:var(--blue)}
  .sub{font-size:14px}
  .card{padding:16px;border-radius:14px}
  .row{flex-direction:column;gap:16px;align-items:stretch}
  .dir-cards{grid-template-columns:1fr}
  .q-card{padding:22px 16px;gap:18px;border-radius:16px}
  .q-prompt .w{font-size:44px}
  .opts{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
  .opt{font-size:20px;min-height:56px}
  .val-row{flex-direction:column-reverse;align-items:stretch;text-align:center;gap:10px}.val-row .btn{width:100%}
  .fb{flex-direction:column;align-items:stretch}.fb .acts{flex-direction:column;align-items:stretch}.fb .acts .btn,.fb .acts .listen{width:100%;justify-content:center}
  .vrow{grid-template-columns:34px 1fr 1fr;}.vrow .c4,.vrow .c5{display:none}
  .hide-m{display:none}
  .stack-m td,.stack-m th{padding:10px 4px}
}

.tag{display:inline-block;background:#FFF1D6;color:#8A5A00;font-weight:600;border-radius:999px;padding:2px 10px;margin:0 3px}
/* auth pages */
.auth-body{background:var(--bg)}
.auth{display:flex;min-height:100vh}
.auth-left{flex:1;background:#1B2033;color:#fff;padding:56px;display:flex;flex-direction:column;justify-content:space-between;gap:40px}
.auth-logo{font-family:'Bricolage Grotesque',sans-serif;font-weight:800;font-size:34px;letter-spacing:-.01em}
.auth-mid h1{font-size:52px;line-height:1.08;margin:0}
.auth-mid p{margin:16px 0 0;font-size:18px;line-height:1.5;color:#C9CEE0;max-width:420px}
.auth-samples{display:flex;flex-direction:column;gap:10px;font-family:'IBM Plex Mono',monospace;font-size:17px;opacity:.9}
.auth-right{flex:1;display:flex;align-items:center;justify-content:center;padding:40px}
.auth-box{width:400px;max-width:100%}
.auth-tabs{display:flex;gap:8px;margin-bottom:28px}
.auth-tabs a{display:inline-flex;align-items:center;min-height:44px;padding:0 22px;border-radius:999px;font-weight:600;text-decoration:none;color:var(--ink);background:#fff;border:1.5px solid var(--line)}
.auth-tabs a.on{background:var(--ink);color:#fff;border-color:var(--ink)}
.auth-h{font-family:'Bricolage Grotesque',sans-serif;font-weight:800;font-size:32px;margin:0;line-height:1.1}
.auth-sub{margin:6px 0 22px;font-size:16px;color:var(--muted);line-height:1.5}
.auth-box input[type=text],.auth-box input[type=password],.auth-box input[type=email]{width:100%;font-family:inherit;font-size:17px;padding:13px 16px;border-radius:10px;border:1.5px solid var(--line);background:#fff;color:var(--ink)}
.rules{margin-top:12px;display:flex;flex-direction:column;gap:5px}
.rule{display:flex;gap:8px;align-items:center;font-size:14px;color:var(--muted)}
.rule .dot{width:18px;height:18px;border-radius:999px;display:inline-flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;background:#ECE7DA;color:#8A8F9C}
.rule.ok{color:var(--green)}.rule.ok .dot{background:var(--green-l);color:var(--green)}
.codeboxes{display:flex;gap:8px}
.auth-box .codeboxes input.cb{width:46px;height:56px;padding:0;text-align:center;font-family:'IBM Plex Mono',monospace;font-weight:600;font-size:26px;border-radius:10px;border:1.5px solid var(--line);background:#fff}
.auth-box .codeboxes input.cb:focus{outline:3px solid #9fb0f0;border-color:var(--blue)}
.link-btn{background:none;border:0;padding:0;font:inherit;font-weight:600;color:var(--blue);cursor:pointer;text-decoration:underline}
.link-btn:disabled{color:var(--muted);cursor:default;text-decoration:none}
@media (max-width:760px){
  .auth{flex-direction:column}
  .auth-left{padding:24px 20px 20px;gap:6px;flex:none}
  .auth-logo{font-size:30px}
  .auth-mid h1{font-size:0}.auth-mid h1::after{content:'Learn the irregular verbs.';font-size:15px;font-weight:400;color:#C9CEE0;font-family:'IBM Plex Sans',sans-serif}
  .auth-mid p,.auth-samples{display:none}
  .auth-right{padding:22px 20px;align-items:flex-start}
  .auth-h{font-size:26px}.auth-sub{font-size:14px}
  .auth-box .codeboxes{justify-content:space-between;gap:6px}.auth-box .codeboxes input.cb{width:42px;height:52px}
}