*{box-sizing:border-box}
img{max-width:100%;height:auto}
html{background:var(--bg)}
html,body{margin:0;min-height:100%;font-family:"Space Grotesk",ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--text);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
body{display:flex;justify-content:center;background:var(--bg)}
button,input,textarea,select{font:inherit}
button{cursor:pointer}
button:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible{outline:2px solid rgba(18,95,255,.28);outline-offset:2px}
a{text-decoration:none;color:inherit}
::selection{background:#dfe6ff;color:var(--text)}

/* Compact contextual help: long explanations live behind a tiny i control. */
uo-info{display:inline-grid;place-items:center;width:18px;height:18px;flex:0 0 18px;border:1px solid #cbd6e5;border-radius:50%;background:#fff;color:#66778e;font:800 10px/1 "Space Grotesk",sans-serif;cursor:help;vertical-align:middle;user-select:none;transition:border-color .12s ease,color .12s ease,background .12s ease}uo-info:hover,uo-info:focus-visible{border-color:#8aa6cc;background:#f7f9fc;color:var(--primary);outline:0}.uo-info-popover{position:fixed;z-index:10050;width:max-content;max-width:min(340px,calc(100vw - 20px));padding:9px 10px;border:1px solid #cfd9e7;border-radius:6px;background:#10233f;color:#fff;font:600 11px/1.45 "Space Grotesk",sans-serif;box-shadow:0 10px 30px rgba(16,35,63,.18);pointer-events:none;opacity:0;transform:translateY(-2px);transition:opacity .1s ease,transform .1s ease;white-space:normal}.uo-info-popover.visible{opacity:1;transform:none}@media(max-width:700px){uo-info{width:20px;height:20px;flex-basis:20px}.uo-info-popover{max-width:calc(100vw - 24px);font-size:12px}}

.app-shell{width:100%;max-width:500px;min-height:100vh;background:var(--bg);position:relative;overflow-x:hidden}
.app-view{min-height:100vh;padding-bottom:82px;background:var(--bg)}
.hidden{display:none!important}

/* Unified customer loading state. Keep route changes calm, informative and mobile-first. */
.app-loading-state{width:100%;min-height:clamp(230px,42vh,390px);display:grid;place-items:center;align-content:center;gap:22px;padding:34px 24px;color:var(--text);text-align:center;overflow:hidden}
.app-loading-main{display:flex;flex-direction:column;align-items:center;gap:13px;min-width:0}
.app-loading-main>strong{max-width:360px;color:#002050;font-size:14px;font-weight:800;line-height:1.35;letter-spacing:-.01em}
.app-loading-spinner{position:relative;width:48px;height:48px;display:grid;place-items:center;flex:0 0 auto;border:1px solid #d9e4f1;border-radius:14px;background:#fff}
.app-loading-spinner::before{content:"";width:22px;height:22px;border:3px solid #dfe8f4;border-top-color:#125fff;border-right-color:#f86000;border-radius:50%;animation:spin .8s linear infinite}
.app-loading-spinner>i{position:absolute;width:5px;height:5px;border-radius:50%;background:#002050}
.app-loading-skeleton{width:min(100%,420px);display:grid;gap:8px}
.app-loading-skeleton>i{display:block;height:8px;border-radius:4px;background:#e5ebf3;animation:app-loader-pulse 1.15s ease-in-out infinite}
.app-loading-skeleton>i:nth-child(1){width:100%}.app-loading-skeleton>i:nth-child(2){width:76%;justify-self:center;animation-delay:.12s}.app-loading-skeleton>i:nth-child(3){width:52%;justify-self:center;animation-delay:.24s}
@keyframes app-loader-pulse{0%,100%{opacity:.45}50%{opacity:1}}
@media(max-width:760px){.app-loading-state{min-height:48vh;gap:18px;padding:28px 22px calc(96px + env(safe-area-inset-bottom))}.app-loading-main>strong{font-size:13px}.app-loading-spinner{width:46px;height:46px}.app-loading-skeleton{width:min(86vw,330px)}}
@media(prefers-reduced-motion:reduce){.app-loading-spinner::before,.app-loading-skeleton>i{animation-duration:2.4s}}

/* Layout */
.page{padding:var(--content-pad)}
.stack{display:flex;flex-direction:column;gap:14px}
.row{display:flex;align-items:center;gap:12px}
.row.between{justify-content:space-between}
.grow{flex:1;min-width:0}
.muted{color:var(--muted)}
.small{font-size:12px}
.tiny{font-size:10.5px}
.title-lg{margin:0;font-size:28px;line-height:1.12;font-weight:800;letter-spacing:-.045em}
.title-md{margin:0;font-size:18px;line-height:1.25;font-weight:750;letter-spacing:-.025em}
.section-title{display:flex;align-items:center;justify-content:space-between;gap:14px;margin:8px 0 0}
.section-title h3{margin:0;font-size:15px;font-weight:750;letter-spacing:-.015em}
.link-btn{border:0;background:transparent;color:var(--primary);font-weight:700;font-size:12px;padding:5px 0}

/* Header */
.topbar{position:sticky;top:0;z-index:25;min-height:68px;display:flex;align-items:center;justify-content:space-between;gap:14px;padding:10px var(--content-pad);background:#fff;border-bottom:1px solid #e2e8f0}
.topbar-main{min-width:0;align-items:center;gap:10px}
.topbar-head{display:flex;flex-direction:column;justify-content:center;min-width:0}
.topbar-title{font-size:17px;font-weight:800;letter-spacing:-.03em;line-height:1.1}
.topbar-wordmark{display:block;width:112px;max-width:36vw;height:auto;object-fit:contain}
.topbar-brand-lockup{display:flex;align-items:center;gap:10px;min-width:0}
.topbar-brand-sub{display:inline-flex;align-items:center;min-height:24px;padding:0 9px;border-left:1px solid #dbe3ee;color:#62728a;font-size:10px;font-weight:750;white-space:nowrap}
.topbar-sub{font-size:10.5px;color:var(--muted);margin-top:3px;line-height:1.25;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.topbar-actions{display:flex;align-items:center;justify-content:flex-end;gap:8px;flex:0 0 auto}
.topbar-wallet-chip{display:grid;grid-template-columns:18px auto auto;align-items:center;gap:7px;min-height:38px;padding:0 11px;border:1px solid #d8e1ec;border-radius:7px;background:#fff;color:var(--text-2);font:inherit;cursor:pointer;white-space:nowrap}.topbar-wallet-chip i{display:grid;place-items:center;width:18px;color:var(--primary);font-size:12px}.topbar-wallet-chip span{font-size:10px;font-weight:700;color:var(--muted)}.topbar-wallet-chip strong{font-size:11.5px;font-weight:850;color:var(--text);font-variant-numeric:tabular-nums}.topbar-wallet-chip:hover{border-color:#b8c8df;background:#f8fafc}.topbar-wallet-chip:focus-visible{outline:2px solid rgba(18,95,255,.18);outline-offset:2px}
.topbar-profile-chip{display:flex;align-items:center;gap:5px;min-height:38px;padding:0 5px;border:1px solid transparent;border-radius:7px;background:transparent;color:#7a889a;cursor:pointer}.topbar-profile-chip:hover{border-color:#dbe3ed;background:#f8fafc}.topbar-profile-chip .avatar.sm{width:32px;height:32px;border-radius:7px}.topbar-profile-chip>.fa-chevron-down{font-size:8px;margin-right:2px}
.icon-btn{width:40px;height:40px;flex:0 0 auto;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--surface);display:grid;place-items:center;color:var(--text-2);transition:background .12s ease,border-color .12s ease,color .12s ease,transform .12s ease}
.icon-btn:active{transform:translateY(1px)}
.icon-btn.primary{background:var(--primary);border-color:var(--primary);color:#fff}
.icon-btn.flat{border-color:transparent;background:transparent}

/* Surfaces */
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:14px;box-shadow:0 1px 2px rgba(18,35,63,.035)}

/* Brand + avatar */
.avatar{width:46px;height:46px;border-radius:9px;background:var(--surface-3);border:1px solid var(--line);display:grid;place-items:center;color:var(--text-2);font-size:13px;font-weight:800;letter-spacing:-.03em;flex:0 0 auto;overflow:hidden}
.avatar.sm{width:36px;height:36px;border-radius:8px;font-size:11px}
.avatar.lg{width:76px;height:76px;border-radius:12px;font-size:22px}
.avatar.teacher{background:#edf2ff;color:#274ccf;border-color:#d9e2ff}
.avatar.student{background:#f1f4f8;color:#44556c}

/* Status */
.badge{display:inline-flex;align-items:center;gap:5px;padding:4px 7px;border-radius:5px;border:1px solid #d8e1eb;background:#f7f9fb;color:#607087;font-size:10px;font-weight:750;line-height:1.15}
.badge.primary{border-color:#dce4ff;background:var(--primary-soft);color:var(--primary)}
.badge.success{border-color:#cfeada;background:var(--success-soft);color:var(--success)}
.badge.warn{border-color:#efd39a;background:#fff8e8;color:#8a5a08}
.badge.danger{border-color:#efc7cf;background:#fff3f5;color:var(--danger)}
.status-dot{width:6px;height:6px;border-radius:50%;display:inline-block;background:var(--success)}
.status-dot.draft{background:var(--warning)}

/* Buttons */
.btn{min-height:42px;border:1px solid transparent;border-radius:7px;padding:0 13px;font-weight:780;font-size:12px;letter-spacing:-.01em;display:inline-flex;align-items:center;justify-content:center;gap:7px;transition:background .12s ease,border-color .12s ease,color .12s ease,transform .12s ease}
.btn:active{transform:translateY(1px)}
.btn.primary{background:var(--brand-gradient);border-color:transparent;color:#fff}
.btn.primary:hover{filter:brightness(.96);border-color:transparent}
.btn.secondary{background:var(--surface);border-color:var(--line);color:var(--text)}
.btn.secondary:hover{background:var(--surface-2);border-color:var(--line-strong)}
.btn.outline{background:var(--surface);color:var(--primary);border-color:#bfcdfd}
.btn.danger{background:var(--danger-soft);border-color:#f2ccd3;color:var(--danger)}
.btn.success{background:var(--success-soft);border-color:#9fd7b3;color:#217548}
.btn.danger-text{background:#fff;border-color:#e4bec4;color:#a32d3a}
.btn.danger-text:hover{background:#fff6f7;border-color:#d7929d}
.btn.full{width:100%}
.btn.small{min-height:36px;padding:0 11px;font-size:11.5px}
.btn[disabled],button[disabled]{opacity:.5;cursor:not-allowed;transform:none}

/* Forms */
.form-group{display:flex;flex-direction:column}
.label{display:block;font-size:11px;color:#53637a;font-weight:750;margin-bottom:7px}
.input,.textarea,.select{width:100%;border:1px solid var(--line);background:#fff;border-radius:7px;padding:11px 12px;outline:none;color:var(--text);font-size:12.5px;transition:border-color .12s ease,box-shadow .12s ease,background .12s ease}
.input{height:44px}
.input::placeholder,.textarea::placeholder{color:#9aa6b5}
.input:focus,.textarea:focus,.select:focus{border-color:#8ba3ff;box-shadow:0 0 0 3px rgba(18,95,255,.08);background:#fff}
.textarea{min-height:96px;resize:vertical;line-height:1.5}

/* Compact info contract: labels and their i-help stay on one line. */
:where(h1,h2,h3,h4):has(+uo-info){display:inline-block!important;max-width:calc(100% - 30px);margin-right:0!important;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;vertical-align:middle}
:where(h1,h2,h3,h4)+uo-info{margin-left:6px;vertical-align:middle}
:where(strong,b,span):has(+uo-info){display:inline!important;vertical-align:middle}
:where(strong,b,span)+uo-info{margin-left:6px;vertical-align:middle}

/* UstozOne canonical MathLive keyboard — v20.63.0 dense, balanced, no clipped labels. */
body{
  --keyboard-zindex:3000;
  --keyboard-accent-color:#002050;
  --keyboard-toolbar-text:#53637a;
  --keyboard-toolbar-text-active:#002050;
  --keyboard-toolbar-background:#ffffff;
  --keyboard-toolbar-background-hover:#f5f8fc;
  --keyboard-toolbar-background-selected:#edf3fb;
  --keyboard-border:1px solid #cbd7e6;
  --keyboard-horizontal-rule:1px solid #dde5ef;
  --keycap-background:#ffffff;
  --keycap-background-hover:#f3f6fa;
  --keycap-background-active:#eaf1fb;
  --keycap-background-pressed:#e0e9f5;
  --keycap-border:1px solid #c7d3e2;
  --keycap-border-bottom:1px solid #aebed1;
  --keycap-text:#10284e;
  --keycap-text-active:#002050;
  --keycap-text-hover:#002050;
  --keycap-text-pressed:#002050;
  --keycap-primary-background:#002050;
  --keycap-primary-text:#ffffff;
  --keycap-secondary-background:#eef3f8;
  --keycap-secondary-background-hover:#e4ebf3;
  --keycap-secondary-text:#10284e;
  --keycap-secondary-border:1px solid #bdcad9;
  --keycap-secondary-border-bottom:1px solid #aab9cb;
  --keyboard-toolbar-font-size:11.5px;
  --keycap-height:40px;
  --keycap-font-size:14px;
  --keycap-small-font-size:10px;
  --keycap-extra-small-font-size:9px;
  --keycap-gap:4px;
  --keycap-max-width:70px;
  --keyboard-padding-horizontal:6px;
  --keyboard-padding-top:5px;
  --keyboard-padding-bottom:6px;
  --keyboard-row-padding-left:2px;
  --keyboard-row-padding-right:2px;
}
@media(max-width:640px){body{--keyboard-toolbar-font-size:10.5px;--keycap-height:40px;--keycap-font-size:13.5px;--keycap-small-font-size:9.5px;--keycap-extra-small-font-size:8.5px;--keycap-gap:3px;--keycap-width:31px;--keycap-max-width:64px;--keyboard-padding-horizontal:4px;--keyboard-padding-top:4px;--keyboard-padding-bottom:5px;--keyboard-row-padding-left:0px;--keyboard-row-padding-right:0px}}

/* Shared controls must work before any app-specific stylesheet loads. */
.topbar-right{display:flex;align-items:center;justify-content:flex-end;gap:8px;min-width:0;flex:0 1 auto;flex-wrap:wrap}
.topbar-title{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.topbar-wallet-chip{max-width:100%;flex-shrink:0}
.topbar-wallet-chip strong{min-width:0;overflow:hidden;text-overflow:ellipsis}