:root{
    /* Brand */
    --main-blue: #00457C;
    --accent: #1da1f2;

    /* Surfaces & text */
    --bg: #f0f4f9;
    --shell: #ffffff;         /* unified container surface */
    --ink: #0f172a;
    --muted: #5b6575;
    --line: #e6edf6;

    /* Layout & motion */
    --container: 1200px;
    --radius: 20px;
    --shadow: 0 18px 50px rgba(15, 23, 42, .12);
    --ring: 0 0 0 3px rgba(29,161,242,.18);
    --h1: clamp(30px, 4.8vw, 50px);
    --h2: clamp(16px, 2vw, 18px);
    --body: clamp(14px, 1.6vw, 16px);
    --speed: 260ms;

    /* Sidebar */
    --sidebar-w: 280px;
    --sidebar-z: 60;
    --sticky-top: 16px;
  }

  @media (prefers-color-scheme: dark){
    :root{
      --bg: #0c111a;
      --shell: #0e1624;
      --ink: #e8eefc;
      --muted: #a1abc2;
      --line: #1e293b;
      --shadow: 0 18px 50px rgba(0,0,0,.5);
      --ring: 0 0 0 3px rgba(29,161,242,.34);
    }
  }

  *,*::before,*::after{ box-sizing: border-box; }
  html,body{ height:100%; }


  /* ==== Unified Shell (single box) ==== */
  .wrap { max-width: var(--container); margin: 0 auto; }
  .unibox{
    background: var(--shell);
    /* border: 1px solid var(--line); */
    /* border-radius: var(--radius); */
    box-shadow: var(--shadow);
    overflow: hidden;                 /* keeps internal edges clean */
  }

  /* Header (used to be hero-card) */
  .header{
    padding: clamp(22px, 3.8vw, 36px);
    background:
      linear-gradient(180deg, color-mix(in oklab, var(--main-blue) 6%, transparent), transparent);
    border-bottom: 1px solid var(--line); /* internal divider */
  }
  .header h1{
    margin:0 0 8px;
    font-size: var(--h1);
    line-height: 1.05;
    letter-spacing: -0.02em;
    background: linear-gradient(180deg, color-mix(in oklab, var(--main-blue) 92%, white 8%), color-mix(in oklab, var(--main-blue) 70%, black 30%));
    -webkit-background-clip: text; background-clip: text; color: transparent;
    font-weight: 800;
  }
  .lead{ color: var(--muted); margin: 0 0 16px; max-width: 70ch; }

  .search{
    position: relative;
    display: flex; align-items: center;
  }
  .search input{
    width: 100%;
    padding: 14px 44px 14px 44px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: color-mix(in oklab, var(--shell) 94%, #fff 6%);
    outline: none;
    transition: border-color var(--speed), box-shadow var(--speed);
    color: var(--ink);
  }
  .search input:focus{ border-color: color-mix(in oklab, var(--main-blue) 45%, var(--line)); box-shadow: var(--ring); }
  .search .icon{
    position:absolute; left:14px; width:20px; height:20px; opacity:.7;
  }

  /* Layout (Sidebar + Content) INSIDE the single shell */
  .layout {
    display: grid;
    grid-template-columns: var(--sidebar-w) 1fr;
    gap: 0; /* no gap—same box */
    min-height: 420px;
  }

  /* Sidebar (no box — just a column with an inner divider) */
  .sidebar{
    position: relative;
    z-index: var(--sidebar-z);
    border-right: 1px solid var(--line);       /* internal divider line */
    background: transparent;
  }
  .sidebar-inner{
    position: sticky; top: var(--sticky-top);
    padding: 16px;
  }
  .side-title{
    margin: 6px 8px 10px;
    font-size: 14px;
    font-weight: 800;
    letter-spacing: .08em;
    text-transform: uppercase;
    color: var(--muted);
  }
  .cat-list {
    list-style: none; padding: 0; margin: 0;
    display: flex; flex-direction: column; gap: 6px;
  }
  .cat-btn {
    width: 100%;
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: 10px;
    background: transparent;
    border: 1px solid transparent;
    color: var(--ink);
    padding: 10px 12px;
    border-radius: 12px;
    text-align: left;
    cursor: pointer;
    transition: background var(--speed), border-color var(--speed), transform var(--speed);
  }
  .cat-btn:hover { background: color-mix(in oklab, var(--main-blue) 6%, transparent); }
  .cat-btn:focus-visible { outline: none; box-shadow: var(--ring); }
  .cat-btn[aria-pressed="true"]{
    background: color-mix(in oklab, var(--main-blue) 10%, transparent);
    border-color: color-mix(in oklab, var(--main-blue) 35%, var(--line));
  }
  .cat-count{
    font: 700 12px/1 var(--body);
    color: color-mix(in oklab, var(--main-blue) 92%, #fff);
    background: color-mix(in oklab, var(--main-blue) 12%, transparent);
    border: 1px solid var(--line);
    padding: 6px 8px;
    border-radius: 999px;
  }

  /* Content column */
  main{ padding: 18px 18px 26px; }
  .filters { display:flex; flex-wrap: wrap; gap: 10px; margin: 0 0 14px; }
  .chip {
    display:inline-flex; align-items:center; gap:8px;
    padding: 8px 12px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: color-mix(in oklab, var(--shell) 96%, white 4%);
    color: var(--muted);
    font-weight: 600;
  }
  .chip strong{ color: var(--ink); }
  .chip .x {
    width: 18px; height: 18px; border-radius: 50%;
    border: 1px solid var(--line); display:grid; place-items:center; cursor:pointer;
  }
  .chip .x:focus-visible{ outline:none; box-shadow: var(--ring); }

  /* FAQ list — now flat, with only row dividers */
  .faq-list{ border-top: 1px solid var(--line); }
  .faq-item{ border-bottom: 1px solid var(--line); }
  .faq-head{
    display:grid;
    grid-template-columns: auto 1fr auto;
    align-items:center;
    gap: 14px;
    width:100%;
    background: transparent;
    border:0;
    padding: 20px;
    cursor:pointer;
    text-align:left;
    font-weight: 700;
    font-size: var(--h2);
    letter-spacing: -.01em;
    color: var(--ink);
  }
  .faq-num{
    width: 28px; height: 28px; border-radius: 8px;
    display:grid; place-items:center;
    font: 700 13px/1 var(--body);
    color: color-mix(in oklab, var(--main-blue) 96%, #fff);
    background: color-mix(in oklab, var(--main-blue) 12%, transparent);
    border: 1px solid var(--line);
  }
  .faq-title{ padding-right: 12px; }
  .pm{
    position: relative;
    width: 22px; height: 22px; border-radius: 6px;
    border: 1px solid var(--line);
  }
  .pm::before,.pm::after{
    content:""; position:absolute; inset:0; margin:auto; background: currentColor;
    transition: transform var(--speed) ease, opacity var(--speed) ease;
    color: #0b1220;
  }
  .pm::before{ width: 12px; height: 2px; } /* horizontal */
  .pm::after{ width: 2px; height: 12px; }  /* vertical */
  .faq-item[aria-expanded="true"] .pm::after{ transform: scaleY(0); opacity:.2; }

  .faq-panel{ overflow: hidden; height: 0; transition: height var(--speed) ease; will-change: height; }
  .faq-inner{ padding: 0 20px 20px 64px; color: var(--muted); }
  .faq-inner p{ margin: 0 0 12px; }

  .faq-head:focus-visible{ outline: none; box-shadow: var(--ring); border-radius: 10px; }

  /* Mobile sidebar offcanvas, still visually part of the single shell */
  .sidebar-toggle { display: none; margin-top: 14px; }
  .btn {
    display:inline-flex; align-items:center; gap:10px;
    background: color-mix(in oklab, var(--shell) 96%, white 4%);
    border: 1px solid var(--line);
    padding: 12px 14px;
    border-radius: 999px;
    cursor: pointer;
    font-weight: 600;
    box-shadow: none;
  }
  .btn:focus-visible { outline: none; box-shadow: var(--ring); }

  @media (max-width: 980px){
    .layout{ grid-template-columns: 1fr; }
    .sidebar-toggle{ display: block; }
    .sidebar {
      position: fixed;
      inset: 0 0 0 auto;
      width: min(86vw, 340px);
      transform: translateX(110%);
      transition: transform var(--speed) ease;
      background: var(--shell);   /* looks like part of shell */
      border-left: 1px solid var(--line);
      border-right: none;
      box-shadow: var(--shadow);
      z-index: var(--sidebar-z);
    }
    .sidebar.open { transform: translateX(0%); }
    .sidebar-inner{ height: 100%; overflow: auto; padding: 18px; }
    .backdrop {
      content:"";
      position: fixed; inset:0; background: rgba(2,6,23,.35);
      opacity: 0; pointer-events: none;
      transition: opacity var(--speed) ease;
      z-index: calc(var(--sidebar-z) - 1);
    }
    .backdrop.show{ opacity: 1; pointer-events: auto; }
    main{ padding: 18px; }
    .faq-inner{ padding: 0 18px 18px 56px; }
  }