:root {
        color-scheme: dark;
        --bg0: #0b0c0b;
        --bg1: #151613;
        --panel: rgba(242, 239, 231, 0.035);
        --panel-border: rgba(242, 239, 231, 0.12);
        --text: #f2efe7;
        --muted: #b8b1a3;
        --accent: #d7b56d;
        --accent-2: #f0cf7f;
        --button-text: #0a0a10;
      }

      * {
        box-sizing: border-box;
      }

      :focus-visible {
        outline: 2px solid var(--accent);
        outline-offset: 3px;
      }

      @media (prefers-reduced-motion: reduce) {
        *, *::before, *::after {
          animation-duration: 0.01ms !important;
          animation-iteration-count: 1 !important;
          scroll-behavior: auto !important;
          transition-duration: 0.01ms !important;
        }
      }
      body {
        margin: 0;
        min-height: 100vh;
        font-family: "Segoe UI", "Inter", system-ui, sans-serif;
        color: var(--text);
        background: var(--bg0);
      }

      .shell {
        max-width: 980px;
        margin: 0 auto;
        padding: 32px 20px 56px;
      }

      .skip-to-content {
        position: fixed;
        top: 8px;
        left: 8px;
        z-index: 1000;
        padding: 12px 16px;
        color: var(--text);
        background: var(--bg0);
        transform: translateY(calc(-100% - 16px));
      }

      .skip-to-content:focus {
        transform: none;
        outline: 2px solid var(--accent);
      }

      .topbar {
        display: grid;
        grid-template-columns: max-content minmax(0, 1fr);
        align-items: center;
        gap: 20px;
        margin-bottom: 32px;
      }

      .brand {
        display: inline-flex;
        align-items: center;
        gap: 7px;
        color: var(--text);
        font-size: 20px;
        font-weight: 600;
        letter-spacing: -0.02em;
        line-height: 1;
        white-space: nowrap;
      }

      .brand-mark {
        position: relative;
        display: inline-block;
        flex: 0 0 15px;
        width: 15px;
        height: 21px;
        border-top: 4px solid currentColor;
        border-bottom: 4px solid currentColor;
        transform: skewY(-13deg);
      }

      .brand-mark::after {
        position: absolute;
        top: 4px;
        left: 0;
        width: 10px;
        height: 4px;
        background: currentColor;
        content: "";
      }

      nav {
        display: flex;
        flex-wrap: wrap;
        gap: 10px;
      }

      .topbar-actions {
        display: flex;
        min-width: 0;
        align-items: center;
        justify-content: flex-end;
        gap: 12px;
      }

      .desktop-site-nav {
        min-width: 0;
        flex: 1 1 auto;
        align-items: center;
        justify-content: flex-end;
        flex-wrap: nowrap;
        gap: 2px;
      }

      .mobile-site-nav {
        display: none;
        position: relative;
        flex-shrink: 0;
      }

      .mobile-site-nav > summary {
        min-height: 38px;
        align-items: center;
        padding: 8px 12px;
        border: 1px solid var(--panel-border);
        border-radius: 4px;
        color: var(--text);
        background: rgba(16, 17, 15, 0.72);
        cursor: pointer;
        list-style: none;
      }

      .mobile-site-nav > summary::-webkit-details-marker {
        display: none;
      }

      .nav-link {
        flex: 0 0 auto;
        padding: 10px 7px 8px;
        border: 0;
        border-bottom: 2px solid transparent;
        border-radius: 2px;
        color: var(--muted);
        font-size: 14px;
        line-height: 1.2;
        white-space: nowrap;
        text-decoration: none;
      }

      .desktop-site-nav .nav-link:hover {
        color: var(--text);
        background: transparent;
        text-decoration: underline;
        text-decoration-color: var(--accent);
        text-underline-offset: 5px;
      }

      .desktop-site-nav .nav-link.active {
        color: var(--text);
        border-bottom-color: var(--accent);
        background: transparent;
        font-weight: 600;
      }

      .hero {
        margin-bottom: 22px;
      }

      .eyebrow {
        margin: 0 0 10px;
        color: var(--accent);
        text-transform: uppercase;
        letter-spacing: 0.12em;
        font-size: 0.82rem;
        font-weight: 700;
      }

      h1 {
        margin: 0 0 12px;
        font-size: clamp(2rem, 5vw, 3.2rem);
        line-height: 1.02;
      }

      .summary {
        max-width: 760px;
        margin: 0;
        color: var(--muted);
        font-size: 1.02rem;
        line-height: 1.65;
      }

      .grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
        gap: 16px;
      }

      
      .card {
        padding: 18px 18px 16px;
        border-radius: 6px;
        background: var(--panel);
        border: 1px solid var(--panel-border);
        box-shadow: none;
      }

      .card h2 {
        margin: 0 0 10px;
        font-size: 1rem;
      }

      .card p {
        margin: 0 0 10px;
        color: var(--muted);
        line-height: 1.6;
      }

      .card ul {
        margin: 0;
        padding-left: 18px;
        color: var(--text);
        line-height: 1.55;
      }

      .card li + li {
        margin-top: 8px;
      }
    

      a {
        color: var(--accent);
      }

      footer {
        margin-top: 28px;
        padding-top: 16px;
        border-top: 1px solid var(--panel-border);
        color: var(--muted);
        line-height: 1.6;
      }

      .accent {
        color: var(--accent-2);
      }

      @media (max-width: 1023px) {
        .topbar {
          grid-template-columns: minmax(0, 1fr) auto;
          gap: 12px;
          align-items: center;
          margin-bottom: 24px;
        }

        .topbar-actions {
          width: auto;
          flex-wrap: nowrap;
        }

        .desktop-site-nav {
          display: none;
        }

        .mobile-site-nav {
          display: block;
        }

        .mobile-site-nav > summary {
          display: inline-flex;
        }

        .mobile-site-nav:not([open]) > nav {
          display: none;
        }

        .mobile-site-nav[open] > nav {
          position: fixed;
          top: 72px;
          right: 12px;
          z-index: 60;
          display: grid;
          width: min(78vw, 280px);
          max-height: calc(100dvh - 84px);
          overflow-y: auto;
          padding: 8px;
          border: 1px solid var(--panel-border);
          border-radius: 4px;
          background: #151613;
          box-shadow: 0 18px 40px rgba(0, 0, 0, 0.38);
        }

        .mobile-site-nav .nav-link {
          min-height: 40px;
          padding: 10px 12px;
          border: 0;
          border-left: 2px solid transparent;
          border-radius: 2px;
        }

        .mobile-site-nav .nav-link:hover,
        .mobile-site-nav .nav-link.active {
          color: var(--text);
          border-color: transparent;
          border-left-color: var(--accent);
          background: rgba(242, 239, 231, 0.045);
        }

        .mobile-site-nav .nav-link.active {
          font-weight: 600;
        }
      }

      
      .topbar-actions {
        display: flex;
        min-width: 0;
        flex-wrap: wrap;
        align-items: center;
        justify-content: flex-end;
        gap: 12px;
        margin-left: auto;
      }

      .site-auth {
        position: relative;
        min-width: 0;
        max-width: 100%;
        z-index: 50;
        color: #eeeeec;
        font: 14px/1.45 "Inter", system-ui, sans-serif;
        --auth-surface: #181818;
        --auth-field: #111111;
        --auth-border: #3b3b39;
        --auth-text: #eeeeec;
        --auth-muted: #aaa9a4;
        --auth-focus: #e1d9bc;
      }

      .site-auth.is-floating {
        position: fixed;
        top: 14px;
        right: 14px;
        z-index: 1200;
      }

      .site-auth[hidden] {
        display: none !important;
      }

      .site-auth-trigger {
        display: inline-flex;
        max-width: 100%;
        align-items: center;
        gap: 12px;
        min-height: 44px;
        padding: 0 14px;
        border: 1px solid var(--auth-border);
        border-radius: 12px;
        color: var(--auth-text);
        background: transparent;
        box-shadow: none;
        cursor: pointer;
        user-select: none;
        list-style: none;
      }

      .site-auth-trigger::-webkit-details-marker {
        display: none;
      }

      .site-auth-trigger::after {
        width: 7px;
        height: 7px;
        flex: 0 0 7px;
        border-right: 1.5px solid currentColor;
        border-bottom: 1.5px solid currentColor;
        content: "";
        transform: translateY(-2px) rotate(45deg);
      }

      .site-auth-trigger:hover,
      .site-auth[open] > .site-auth-trigger {
        border-color: #eeeeec;
        background: #242424;
      }

      .site-auth-trigger:focus-visible {
        outline: 2px solid var(--auth-focus);
        outline-offset: 3px;
      }

      .site-auth[open] > .site-auth-trigger::after {
        transform: translateY(2px) rotate(225deg);
      }

      [data-site-auth-label] {
        min-width: 0;
        max-width: 14ch;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
      }

      .site-auth-avatar {
        display: none;
      }

      .site-auth-panel {
        position: absolute;
        top: calc(100% + 8px);
        right: 0;
        display: grid;
        gap: 12px;
        box-sizing: border-box;
        width: min(320px, calc(100vw - 28px));
        max-height: min(760px, calc(100vh - 96px));
        overflow-y: auto;
        overscroll-behavior: contain;
        padding: 22px;
        border: 1px solid var(--auth-border);
        border-radius: 8px;
        color: var(--auth-text);
        background: var(--auth-surface);
        box-shadow: 0 8px 24px #0004;
      }

      .site-auth-session-actions > .site-auth-account-link {
        grid-column: 1 / -1;
      }

      .site-auth-footer {
        display: flex;
        flex-wrap: wrap;
        gap: 0 18px;
        margin: 4px 0 0;
        padding-top: 8px;
        border-top: 1px solid var(--auth-border);
      }

      .site-auth-footer a {
        display: inline-flex;
        align-items: center;
        min-height: 44px;
        color: var(--auth-muted);
        font-size: 12px;
        text-decoration: underline;
        text-underline-offset: 3px;
      }

      .site-auth-form input { box-sizing: border-box; }

      .site-auth:not([open]) .site-auth-panel {
        display: none;
      }

      .site-auth-panel :focus-visible {
        outline: 2px solid var(--auth-focus);
        outline-offset: 3px;
      }

      [data-site-auth-status]:empty {
        display: none;
      }

      .site-auth-copy,
      .site-auth-user,
      .site-auth-account-link {
        color: var(--auth-muted);
        font-size: 0.88rem;
        line-height: 1.45;
      }

      .site-auth-user {
        color: var(--auth-text);
        font-weight: 500;
        overflow-wrap: anywhere;
      }

      .site-auth-account-link {
        display: inline-flex;
        align-items: center;
        min-height: 44px;
        color: var(--auth-text);
        font-weight: 500;
        text-decoration: underline;
        text-underline-offset: 3px;
      }

      .site-auth-copy.error {
        color: #ffaaaa;
      }

      .site-auth-copy.success {
        color: #8ce0aa;
      }

      .site-auth-form {
        display: grid;
        gap: 10px;
        min-inline-size: 0;
        margin: 0;
        padding: 0;
        border: 0;
      }

      .site-auth-form[hidden],
      .site-auth-form [hidden],
      .site-auth-session-actions[hidden] {
        display: none !important;
      }

      .site-auth-tabs {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 4px;
      }

      .site-auth-tabs button {
        min-height: 44px;
        padding: 8px 4px;
        border: 0;
        border-bottom: 2px solid transparent;
        color: var(--auth-muted);
        background: transparent;
        font: inherit;
        cursor: pointer;
      }

      .site-auth-tabs button[aria-selected="true"] {
        color: var(--auth-text);
        border-bottom-color: var(--auth-focus);
      }

      .site-auth-fields { display: grid; gap: 10px; }

      .site-auth-form label {
        display: grid;
        gap: 5px;
        color: var(--auth-muted);
        font-size: 0.86rem;
        font-weight: 500;
      }

      .site-auth-form input {
        min-height: 44px;
        width: 100%;
        border: 1px solid var(--auth-border);
        border-radius: 6px;
        padding: 8px 11px;
        color: var(--auth-text);
        background: var(--auth-field);
        font: inherit;
        font-weight: 500;
      }

      .site-auth-form input::placeholder {
        color: #96958f;
      }

      .site-auth-form input:is(:autofill, :-webkit-autofill) {
        box-shadow: 0 0 0 1000px var(--auth-field) inset;
        -webkit-text-fill-color: var(--auth-text);
        caret-color: var(--auth-text);
      }

      .site-auth-form input:focus {
        border-color: var(--auth-focus);
        outline: 2px solid var(--auth-focus);
        outline-offset: 1px;
      }

      .site-auth-actions,
      .site-auth-session-actions {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 8px;
      }

      .site-auth-actions { grid-template-columns: 1fr; }

      .site-auth-actions button,
      .site-auth-session-actions button {
        min-height: 44px;
        border: 1px solid var(--auth-border);
        border-radius: 8px;
        padding: 8px 10px;
        color: var(--auth-text);
        background: transparent;
        font: inherit;
        font-weight: 500;
        cursor: pointer;
      }

      .site-auth-actions button {
        border-color: #eeeeec;
        color: #0a0a10;
        background: #eeeeec;
      }

      .site-auth-actions button:hover,
      .site-auth-session-actions button:hover {
        border-color: #eeeeec;
        background: #292929;
      }

      .site-auth-actions button:hover {
        background: #ffffff;
      }

      .site-auth-actions button:disabled,
      .site-auth-session-actions button:disabled {
        cursor: wait;
        opacity: 0.66;
      }

      @media (max-width: 760px) {
        .topbar-actions {
          width: 100%;
          justify-content: space-between;
        }

        .site-auth {
          margin-left: auto;
        }

        .site-auth.is-floating {
          top: 10px;
          right: 10px;
        }

        body.stem-trainer-public .site-auth.is-floating {
          top: 112px;
          right: 12px;
        }
      }

      .shell {
  max-width: 1180px;
}

.hero,
.grid,
footer {
  max-width: 760px;
  margin-inline: auto;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 2.6rem);
}

.grid {
  display: block;
}

.billing-actions {
  gap: 12px 28px;
  padding-bottom: 20px;
}

.billing-actions a,
.billing-disclosure > summary {
  padding-block: 10px;
}

.card,
.billing-disclosure {
  padding: 24px 0;
  border: 0;
  border-top: 1px solid var(--panel-border);
  border-radius: 0;
  background: transparent;
}

.card p:empty {
  display: none;
}

.card h2 {
  font-size: 1.15rem;
}

.billing-disclosure > summary {
  color: var(--accent);
  cursor: pointer;
}

.billing-disclosure p {
  margin-bottom: 0;
  color: var(--muted);
  line-height: 1.6;
}

.card,
.billing-disclosure,
footer {
  overflow-wrap: anywhere;
}