/* Shared by the landing page and the notes (write-ups): colours, nav, buttons, the signup
   card with its thank-you step, the article layout and the footer.

   Style D, The Brief: black, white and grey; Georgia for headings; square corners; colour
   only where it means something (the highlighter that marks a swapped detail in the app,
   red for errors, green for success). The app (PII Check) uses the same style. */
:root, :root[data-theme="light"] {
  --ink: #000000; --paper: #ffffff; --shade: #F2F2F2; --marker: #FFE873;
  --bg: #ffffff;
  --bg-2: #ffffff;
  --panel: #ffffff;
  --panel-2: #F2F2F2;
  --border: #D4D4D4;
  --text: #000000;
  --muted: #595959;      /* 7.0:1 on white */
  --muted-2: #737373;    /* 4.7:1 on white */
  --accent: #000000;
  --accent-2: #000000;
  --accent-dim: rgba(0,0,0,0.06);
  --accent-shadow: transparent;
  --on-accent: #ffffff;
  --danger: #B3261E;     /* 6.5:1 */
  --danger-dim: rgba(179,38,30,0.08);
  --ok: #1E7A34;         /* 5.4:1 */
  --ok-dim: rgba(30,122,52,0.08);
  --purple: #595959;
  --purple-dim: transparent;
  /* The waitlist card: black in light mode. */
  --card-bg: #000000; --card-fg: #ffffff; --card-border: #000000;
  --card-field: #ffffff; --card-field-fg: #000000; --card-field-border: #ffffff;
}
:root[data-theme="dark"] {
  --ink: #F2F2F2; --paper: #121212; --shade: #1E1E1E; --marker: #FFE873;
  --bg: #121212;
  --bg-2: #121212;
  --panel: #121212;
  --panel-2: #1E1E1E;
  --border: #6B6B6B;     /* input edges 3.5:1 */
  --text: #F2F2F2;       /* 16.7:1 */
  --muted: #A3A3A3;      /* 7.4:1 */
  --muted-2: #8C8C8C;    /* 5.6:1 */
  --accent: #F2F2F2;
  --accent-2: #F2F2F2;
  --accent-dim: rgba(242,242,242,0.08);
  --accent-shadow: transparent;
  --on-accent: #121212;
  --danger: #FF8A80;     /* 8.2:1 */
  --danger-dim: rgba(255,138,128,0.12);
  --ok: #5CC97A;         /* 9.0:1 */
  --ok-dim: rgba(92,201,122,0.12);
  --purple: #A3A3A3;
  --purple-dim: transparent;
  /* In dark mode the card stays dark, set off by a light edge, rather than a light block. */
  --card-bg: #1E1E1E; --card-fg: #F2F2F2; --card-border: #F2F2F2;
  --card-field: #121212; --card-field-fg: #F2F2F2; --card-field-border: #6B6B6B;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Helvetica Neue", Helvetica, -apple-system, "Segoe UI", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: background-color 0.15s ease, color 0.15s ease;
  overflow-x: hidden;
}
main { max-width: 1040px; margin: 0 auto; padding: 0 20px; }
section { padding: 64px 0; border-bottom: 1px solid var(--border); }
section:last-of-type { border-bottom: none; }
a { color: var(--ink); text-underline-offset: 3px; }
h1, h2, h3 { font-family: Georgia, "Times New Roman", serif; font-weight: 400; }

/* -- nav: a masthead with a rule under it -- */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1040px;
  margin: 0 auto;
  padding: 20px 20px;
  position: relative;
}
.nav::after { content: ""; position: absolute; left: 20px; right: 20px; bottom: 0; border-bottom: 1px solid var(--ink); }
.brand {
  display: flex; align-items: center; gap: 9px; text-decoration: none;
  font-family: Georgia, "Times New Roman", serif; font-size: 18px;
  color: var(--ink);
}
.brand svg { flex: none; }
.nav-right { display: flex; align-items: center; gap: 18px; }
.nav-links { display: flex; gap: 18px; }
.nav-links a { color: var(--muted); font-size: 13.5px; text-decoration: none; }
.nav-links a:hover { color: var(--ink); text-decoration: underline; }
/* The footer links reach the same sections on small screens. */
@media (max-width: 560px) { .nav-links { display: none; } }
.theme-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 34px; height: 34px;
  border-radius: 1px;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--muted);
  cursor: pointer;
  font-size: 15px;
}
.theme-toggle:hover { color: var(--ink); border-color: var(--ink); }

/* -- headings shared by the hero and the notes -- */
.kicker {
  display: inline-block;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--muted);
  margin-bottom: 18px;
}
h1 {
  font-size: 64px;
  line-height: 1.06;
  letter-spacing: -0.02em;
  margin: 0 0 22px;
  color: var(--ink);
}
/* The same highlighter the app puts on each swapped detail. Black on #FFE873: 17:1. */
h1 .accent-text { background: var(--marker); color: #000; padding: 0 0.08em; }
@media (max-width: 520px) { h1 { font-size: 40px; } }

/* -- buttons -- */
.btn {
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  border-radius: 1px;
  padding: 13px 22px;
  cursor: pointer;
  border: 1px solid var(--ink);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.btn-primary { color: var(--paper); background: var(--ink); }
.btn-primary:hover { opacity: 0.88; }
.btn-primary:disabled { opacity: 0.5; cursor: default; }
.btn-ghost { color: var(--ink); background: transparent; }
.btn-ghost:hover { background: var(--accent-dim); }
/* The nav's own call to action: smaller, and on phones the only link left beside the brand. */
.btn-nav { font-size: 13.5px; padding: 8px 14px; }
@media (max-width: 400px) { .btn-nav { padding: 8px 10px; font-size: 13px; } .brand span { font-size: 16px; } }

/* -- signup: an inverse band in light mode, a ruled dark card in dark mode -- */
.signup-card {
  background: var(--card-bg);
  color: var(--card-fg);
  border: 1px solid var(--card-border);
  border-radius: 1px;
  padding: 44px 40px;
  text-align: left;
}
.signup-card h2 { font-size: 34px; margin: 0 0 12px; color: var(--card-fg); }
.signup-card p { color: var(--card-fg); opacity: 0.8; font-size: 15px; margin: 0 0 24px; line-height: 1.6; max-width: 60ch; }
.signup-card .btn-primary { background: var(--card-fg); color: var(--card-bg); border-color: var(--card-fg); }
.signup-card a { color: var(--card-fg); }
.signup-form {
  display: flex;
  gap: 10px;
  max-width: 520px;
  flex-wrap: wrap;
}
.signup-form input[type="email"], .share-row input {
  flex: 1;
  min-width: 200px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 1px;
  color: var(--text);
  padding: 13px 14px;
  font-size: 15px;
  font-family: inherit;
}
.signup-card .signup-form input[type="email"], .signup-card .share-row input { background: var(--card-field); color: var(--card-field-fg); border-color: var(--card-field-border); }
.signup-form input[type="email"]:focus, .share-row input:focus { outline: 2px solid var(--marker); outline-offset: 1px; }
.form-msg { margin-top: 14px; font-size: 13.5px; min-height: 18px; }
.form-msg.ok { color: var(--ok); }
.form-msg.err { color: var(--danger); }
/* On the inverse band the message colours flip with it. */
.signup-card .form-msg.ok { color: var(--card-fg); font-weight: 600; }
.signup-card .form-msg.err { color: var(--card-fg); font-weight: 600; text-decoration: underline; text-decoration-color: var(--danger); }
.signup-card .privacy-note { font-size: 12.5px; opacity: 0.7; margin: 6px 0 0; }

/* -- after signing up: a share link and one optional question -- */
.thanks { max-width: 520px; }
.thanks .thanks-title { font-size: 20px; font-family: Georgia, serif; margin: 0 0 10px; }
.thanks p { margin: 0 0 16px; }
.share-row { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; }
.share-row input { font-size: 13.5px; }
.share-buttons { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 26px; }
.share-buttons .btn, .share-row .btn { font-size: 13.5px; padding: 10px 16px; }
.signup-card .btn-ghost { color: var(--card-fg); border-color: var(--card-fg); }
.platform { border-top: 1px solid currentColor; padding-top: 20px; }
.platform p { font-size: 13.5px; margin-bottom: 12px; }
.platform-buttons { display: flex; gap: 8px; flex-wrap: wrap; }
.platform-buttons button {
  font-family: inherit; font-size: 13px; color: inherit;
  background: transparent; border: 1px solid currentColor;
  border-radius: 1px; padding: 7px 14px; cursor: pointer;
}
.platform-buttons button:hover, .platform-buttons button[aria-pressed="true"] { background: var(--marker); color: #000; border-color: var(--marker); }

/* -- notes (write-ups) -- */
.article { max-width: 680px; margin: 0 auto; padding: 32px 20px 64px; }
.article header { margin-bottom: 36px; }
.article h1 { font-size: 48px; }
.article .byline { color: var(--muted); font-size: 14px; margin: 0; }
.article h2 { font-size: 28px; letter-spacing: -0.01em; margin: 44px 0 12px; }
.article h3 { font-size: 21px; margin: 30px 0 10px; }
.article p, .article li { font-family: Georgia, "Times New Roman", serif; font-size: 18px; line-height: 1.65; }
.article p { margin: 0 0 18px; }
.article code { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.85em;
                background: var(--panel-2); border: 1px solid var(--border); border-radius: 1px; padding: 1px 5px; }
.article pre { background: var(--panel); border: 1px solid var(--border); border-radius: 1px;
               padding: 16px 18px; overflow-x: auto; font-size: 13.5px; line-height: 1.55; box-shadow: 6px 6px 0 var(--shade); }
.article pre code { background: none; border: none; padding: 0; }
.article blockquote { margin: 0 0 18px; padding: 4px 0 4px 18px; border-left: 3px solid var(--ink); color: var(--muted); }
.article figure { margin: 28px 0; }
.article figure img, .article figure video { width: 100%; border-radius: 1px; border: 1px solid var(--border); }
.article figcaption { font-size: 13px; color: var(--muted); margin-top: 8px; text-align: center; }
.article table { width: 100%; border-collapse: collapse; margin: 0 0 18px; font-size: 14.5px; }
.article th, .article td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--border); }
.article th { border-bottom-color: var(--ink); }
.article .signup-card { margin: 44px 0; }
/* Inside an article the card keeps its own type, not the article's. */
.article .signup-card h2 { font-size: 30px; margin: 0 0 12px; }
.article .signup-card p { font-family: "Helvetica Neue", Helvetica, -apple-system, Arial, sans-serif;
                          font-size: 15px; line-height: 1.6; margin: 0 0 24px; }
.article .signup-card .privacy-note { font-size: 12.5px; margin: 6px 0 0; }
.article .thanks p { margin: 0 0 16px; }
.article .platform p { font-size: 13.5px; margin-bottom: 12px; }

footer {
  max-width: 1040px;
  margin: 0 auto;
  padding: 32px 20px 48px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
  border-top: 1px solid var(--ink);
}
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; margin-bottom: 14px; }
.footer-links a { color: var(--muted); text-decoration: none; }
.footer-links a:hover { color: var(--ink); text-decoration: underline; }