*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    :root {
      --font-sans: 'IBM Plex Sans', system-ui, sans-serif;
      --font-serif: 'IBM Plex Serif', Georgia, serif;
      --font-mono: 'IBM Plex Mono', 'Menlo', monospace;
      --bg:       #ffffff;
      --bg-soft:  #f7f7f5;
      --bg-code:  #1b1b22;
      --text:     #18181b;
      --text-mid: #3f3f46;
      --text-dim: #71717a;
      --border:   #e4e4e7;
      --orange:      #c94b0c;
      --orange-soft: #fff4ed;
      --orange-mid:  #fed7aa;
      --blue:        #1b4fad;
      --blue-soft:   #eff6ff;
      --nav-bg: rgba(255,255,255,0.92);
      --layout-width: 1320px;
      --radius: 5px;
    }

    [data-theme="dark"] {
      --bg:       #13131a;
      --bg-soft:  #1e1e28;
      --bg-code:  #0d0d12;
      --text:     #e4e4e7;
      --text-mid: #a1a1aa;
      --text-dim: #52525b;
      --border:   #2d2d3a;

      --orange:      #f97316;
      --orange-soft: rgba(249,115,22,0.12);
      --orange-mid:  rgba(249,115,22,0.3);
      --blue:        #60a5fa;
      --blue-soft:   rgba(96,165,250,0.1);

      --nav-bg: rgba(19,19,26,0.92);
    }

    html { scroll-behavior: smooth; font-size: 16px; }

    body {
      font-family: var(--font-serif);
      background: var(--bg);
      color: var(--text);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
    }

    /* ─── NAV ─────────────────────────────────────────────── */
    .site-nav {
      position: sticky; top: 0; z-index: 100;
      background: var(--nav-bg);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border);
      font-family: var(--font-sans);
    }
    /* ─── NAV ICONS (GitHub, newsletter, dark toggle) ── */
    .nav-icons {
      margin-left: auto;
      display: flex;
      align-items: center;
      gap: 0.4rem;
      flex-shrink: 0;
    }
    .nav-icon-link {
      display: flex;
      align-items: center;
      padding: 0.3rem 0.4rem;
      color: var(--text-dim);
      border-radius: 6px;
      transition: color 0.15s;
    }
    .nav-icon-link:hover { color: var(--text); }
    .nav-icon-link svg { display: block; }

    /* ─── DARK MODE TOGGLE ────────────────────────────── */
    .dark-toggle {
      background: none;
      border: 1px solid var(--border);
      border-radius: 6px;
      padding: 0.3rem 0.55rem;
      cursor: pointer;
      color: var(--text-dim);
      display: flex;
      align-items: center;
      transition: color 0.15s, border-color 0.15s;
      flex-shrink: 0;
    }
    .dark-toggle:hover { color: var(--text); border-color: var(--text-dim); }
    .dark-toggle svg { display: block; }
    .nav-inner {
      max-width: var(--layout-width);
      margin: 0 auto;
      padding: 0 2rem;
      height: 52px;
      display: flex;
      align-items: center;
      gap: 2rem;
    }
    .nav-brand {
      font-size: 0.78rem; font-weight: 600;
      letter-spacing: 0.12em; text-transform: uppercase;
      color: var(--orange); text-decoration: none; flex-shrink: 0;
    }
    .nav-links { display: flex; gap: 1.5rem; list-style: none; }
    .nav-links a {
      font-size: 0.8rem; font-weight: 500;
      color: var(--text-mid); text-decoration: none; letter-spacing: 0.02em;
    }
    .nav-links a:hover { color: var(--text); }
    .nav-links a.active { color: var(--orange); font-weight: 600; }

    /* ─── HERO ────────────────────────────────────────────── */
    .hero {
      border-bottom: 1px solid var(--border);
      padding: 4rem 2rem 3.5rem;
      max-width: var(--layout-width);
      margin: 0 auto;
    }
    .hero-eyebrow {
      font-family: var(--font-mono); font-size: 0.72rem; font-weight: 500;
      letter-spacing: 0.14em; text-transform: uppercase;
      color: var(--orange); margin-bottom: 1.1rem;
    }
    .hero h1 {
      font-family: var(--font-sans);
      font-size: clamp(2.0rem, 5vw, 3.2rem);
      font-weight: 700; line-height: 1.15;
      letter-spacing: -0.03em; color: var(--text);
      max-width: 760px; margin-bottom: 1.25rem;
    }
    .hero-subtitle {
      font-family: var(--font-serif); font-size: 1.15rem;
      line-height: 1.65; color: var(--text-mid);
      max-width: 600px; margin-bottom: 1rem;
    }
    .hero-hint {
      font-family: var(--font-sans); font-size: 0.82rem;
      color: var(--text-dim); display: flex; align-items: center; gap: 1rem;
    }
    .hero-hint .dot {
      display: inline-block; width: 3px; height: 3px;
      background: var(--border); border-radius: 50%;
    }

    /* ─── FLOW WRAPPER ────────────────────────────────────── */
    .flow-outer {
      max-width: 800px;
      margin: 0 auto;
      padding: 3.5rem 2rem 6rem;
    }

    /* ─── CONNECTOR ───────────────────────────────────────── */
    .flow-connector {
      display: flex;
      align-items: center;
      justify-content: center;
      height: 40px;
      position: relative;
    }
    .flow-connector::before {
      content: '';
      position: absolute;
      left: 50%; top: 0; bottom: 0;
      width: 2px;
      background: var(--border);
      transform: translateX(-50%);
    }
    .flow-connector-label {
      background: var(--bg);
      border: 1px solid var(--border);
      border-radius: 20px;
      padding: 0.15rem 0.75rem;
      font-family: var(--font-sans);
      font-size: 0.7rem;
      font-weight: 600;
      letter-spacing: 0.06em;
      text-transform: uppercase;
      color: var(--text-dim);
      position: relative;
      z-index: 1;
    }

    /* ─── QUESTION CARD ───────────────────────────────────── */
    .q-card {
      border: 1.5px solid var(--border);
      border-radius: 8px;
      padding: 1.5rem 1.75rem 1.6rem;
      background: var(--bg);
      transition: border-color 0.15s;
    }
    .q-card:not(.answered):focus-within {
      border-color: var(--text-dim);
    }
    .q-card.answered {
      background: var(--bg-soft);
    }
    .q-card-step {
      font-family: var(--font-mono);
      font-size: 0.67rem; font-weight: 500;
      letter-spacing: 0.12em; text-transform: uppercase;
      color: var(--text-dim); margin-bottom: 0.35rem;
    }
    .q-card-question {
      font-family: var(--font-sans);
      font-size: 1.08rem; font-weight: 600;
      color: var(--text); line-height: 1.35;
      margin-bottom: 0.35rem;
    }
    .q-card-help {
      font-family: var(--font-serif);
      font-size: 0.88rem; color: var(--text-dim);
      line-height: 1.6; margin-bottom: 1.15rem;
    }

    /* choices */
    .q-choices { display: flex; flex-direction: column; gap: 0.55rem; }
    .q-choice-btn {
      display: flex; align-items: flex-start; gap: 0.8rem;
      background: var(--bg);
      border: 1.5px solid var(--border);
      border-radius: 6px;
      padding: 0.8rem 1rem;
      cursor: pointer;
      text-align: left;
      font-family: var(--font-sans);
      transition: border-color 0.12s, background 0.12s;
      width: 100%;
    }
    .q-choice-btn:hover {
      border-color: var(--orange);
      background: var(--orange-soft);
    }
    .q-choice-btn:focus-visible {
      outline: 2px solid var(--orange);
      outline-offset: 2px;
    }
    .q-choice-icon {
      width: 18px; height: 18px;
      border: 1.5px solid var(--border);
      border-radius: 50%;
      flex-shrink: 0; margin-top: 3px;
      transition: border-color 0.12s;
    }
    .q-choice-btn:hover .q-choice-icon { border-color: var(--orange); }
    .q-choice-label {
      font-size: 0.9rem; font-weight: 600;
      color: var(--text); display: block; margin-bottom: 0.1rem;
    }
    .q-choice-sub {
      font-size: 0.82rem; color: var(--text-dim);
      font-family: var(--font-serif); line-height: 1.5;
    }

    /* answered summary */
    .q-answer-summary { display: none; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
    .answered .q-choices { display: none; }
    .answered .q-card-help { display: none; }
    .answered .q-answer-summary { display: flex; }
    .q-ans-question { font-family: var(--font-sans); font-size: 0.83rem; color: var(--text-dim); }
    .q-answer-chip {
      display: inline-flex; align-items: center; gap: 0.3rem;
      background: var(--orange-soft);
      border: 1px solid var(--orange-mid);
      border-radius: 3px;
      padding: 0.1rem 0.55rem;
      font-family: var(--font-sans);
      font-size: 0.82rem; font-weight: 600;
      color: var(--orange);
    }
    .q-change-btn {
      margin-left: auto;
      background: none; border: none; cursor: pointer;
      font-family: var(--font-sans); font-size: 0.78rem;
      color: var(--text-dim); text-decoration: underline; padding: 0;
    }
    .q-change-btn:hover { color: var(--text); }

    /* ─── RESULT CARD ─────────────────────────────────────── */
    .result-card {
      border: 2px solid var(--orange);
      border-radius: 8px;
      overflow: hidden;
    }
    .result-header {
      background: var(--orange);
      color: #fff;
      padding: 1.1rem 1.5rem;
      display: flex;
      align-items: flex-start;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 0.75rem;
    }
    .result-eyebrow {
      font-family: var(--font-mono);
      font-size: 0.67rem; font-weight: 500;
      letter-spacing: 0.13em; text-transform: uppercase;
      opacity: 0.75; margin-bottom: 0.3rem;
    }
    .result-method-name {
      font-family: var(--font-sans);
      font-size: 1.35rem; font-weight: 700;
      letter-spacing: -0.02em; line-height: 1.2;
    }
    .result-tags {
      display: flex; gap: 0.4rem; flex-wrap: wrap;
      align-self: center;
    }
    .result-tag {
      background: rgba(255,255,255,0.22);
      border-radius: 3px;
      padding: 0.15rem 0.55rem;
      font-family: var(--font-sans);
      font-size: 0.7rem; font-weight: 600;
      letter-spacing: 0.05em;
    }
    .result-body { padding: 1.5rem 1.75rem; }
    .result-description {
      font-family: var(--font-serif);
      font-size: 0.97rem; line-height: 1.72;
      color: var(--text-mid); margin-bottom: 1.25rem;
    }

    /* code block */
    .code-block-wrap {
      background: var(--bg-code);
      border-radius: 6px; overflow: hidden;
      margin-bottom: 1.25rem;
    }
    .code-block-label {
      background: rgba(255,255,255,0.06);
      padding: 0.38rem 1rem;
      font-family: var(--font-mono);
      font-size: 0.67rem; font-weight: 500;
      letter-spacing: 0.1em; text-transform: uppercase;
      color: rgba(255,255,255,0.35);
      border-bottom: 1px solid rgba(255,255,255,0.08);
    }
    .code-block-wrap pre {
      margin: 0; padding: 1rem 1.25rem;
      overflow-x: auto;
      font-family: var(--font-mono);
      font-size: 0.82rem; line-height: 1.65;
      color: #e8e8f0;
    }
    .code-block-wrap code { font-family: inherit; }

    /* "why this method" accordion */
    .result-why-toggle {
      display: flex; align-items: center; gap: 0.45rem;
      background: none; border: none; cursor: pointer; padding: 0;
      font-family: var(--font-sans);
      font-size: 0.85rem; font-weight: 600;
      color: var(--orange); margin-bottom: 0.7rem;
    }
    .result-why-toggle:hover { opacity: 0.75; }
    .result-why-toggle:focus-visible { outline: 2px solid var(--orange); outline-offset: 2px; border-radius: 2px; }
    .toggle-arrow { display: inline-block; transition: transform 0.18s; font-style: normal; }
    .result-why-toggle.open .toggle-arrow { transform: rotate(90deg); }
    .result-why-body {
      display: none;
      font-family: var(--font-serif);
      font-size: 0.9rem; line-height: 1.72;
      color: var(--text-mid);
      margin-bottom: 1.1rem;
      padding: 0.9rem 1.1rem;
      border-left: 3px solid var(--orange-mid);
      background: var(--orange-soft);
      border-radius: 0 4px 4px 0;
    }
    .result-why-body.open { display: block; }
    .result-why-body p + p { margin-top: 0.6rem; }

    /* links */
    .result-links { display: flex; gap: 0.65rem; flex-wrap: wrap; margin-top: 0.5rem; }
    .result-link {
      display: inline-flex; align-items: center; gap: 0.3rem;
      font-family: var(--font-sans);
      font-size: 0.81rem; font-weight: 500;
      color: var(--blue);
      text-decoration: none;
      border: 1px solid var(--border);
      border-radius: 4px;
      padding: 0.22rem 0.7rem;
      transition: border-color 0.12s, background 0.12s;
    }
    .result-link:hover { border-color: var(--blue); background: var(--blue-soft); }

    /* reset */
    .flow-reset { margin-top: 1.75rem; text-align: center; }
    .flow-reset-btn {
      background: none;
      border: 1px solid var(--border);
      border-radius: 4px; cursor: pointer;
      font-family: var(--font-sans);
      font-size: 0.82rem; font-weight: 500;
      color: var(--text-dim);
      padding: 0.4rem 1.1rem;
      transition: border-color 0.12s, color 0.12s;
    }
    .flow-reset-btn:hover { color: var(--text); border-color: var(--text-dim); }

    /* hidden */
    .hidden { display: none !important; }

    /* ─── FOOTER ──────────────────────────────────────────── */
    .site-footer {
      border-top: 1px solid var(--border);
      background: var(--bg-soft);
      padding: 2rem;
      font-family: var(--font-sans);
      font-size: 0.78rem;
      color: var(--text-dim);
    }
    .footer-inner {
      max-width: var(--layout-width);
      margin: 0 auto;
      display: flex; align-items: center; justify-content: space-between;
      flex-wrap: wrap; gap: 1rem;
    }
    .footer-links { list-style: none; display: flex; gap: 1.25rem; }
    .footer-links a { color: var(--text-dim); text-decoration: none; }
    .footer-links a:hover { color: var(--text); }

    /* ─── RESPONSIVE ──────────────────────────────────────── */
    @media (max-width: 640px) {
      .nav-links { display: none; }
      .hero { padding: 2.5rem 1.25rem 2rem; }
      .flow-outer { padding: 2rem 1.25rem 4rem; }
      .q-card { padding: 1.2rem 1.1rem; }
      .result-body { padding: 1.2rem 1.1rem; }
      .result-header { padding: 0.9rem 1.1rem; }
    }