/* ============================================================
   The Definitive BMW Z4 E89 — site stylesheet
   Palette: Navy #0A192D | Blue #2F82C8 | Ink #E6EEF6 | Cream #F0F0F5
   ============================================================ */

:root {
  --navy: #0A192D;
  --navy-2: #0F2340;
  --navy-3: #142D52;
  --blue: #2F82C8;
  --blue-2: #4FA0E6;
  --ink: #E6EEF6;
  --ink-dim: #A9BDD3;
  --cream: #F0F0F5;
  --rule: rgba(255,255,255,0.08);
  --shadow: 0 8px 30px rgba(0,0,0,0.35);
  --max: 1140px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--navy);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--blue-2); text-decoration: none; }
a:hover { color: #fff; }

img { max-width: 100%; height: auto; display: block; }

.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 28px;
}

/* ---------- Header ---------- */
.site-header {
  padding: 22px 0;
  border-bottom: 1px solid var(--rule);
  position: sticky;
  top: 0;
  background: rgba(10,25,45,0.92);
  backdrop-filter: blur(10px);
  z-index: 10;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  font-weight: 700;
  letter-spacing: 0.5px;
  font-size: 17px;
  color: #fff;
}
.brand span { color: var(--blue-2); }
.nav a {
  margin-left: 22px;
  color: var(--ink-dim);
  font-size: 15px;
  font-weight: 500;
}
.nav a:hover, .nav a.active { color: #fff; }

/* ---------- Hero ---------- */
.hero {
  padding: 96px 0 72px;
  text-align: center;
  background:
    radial-gradient(ellipse at top, rgba(47,130,200,0.18), transparent 60%),
    linear-gradient(180deg, var(--navy) 0%, var(--navy-2) 100%);
}
.hero .eyebrow {
  letter-spacing: 3px;
  text-transform: uppercase;
  font-size: 13px;
  color: var(--blue-2);
  font-weight: 600;
  margin-bottom: 18px;
}
.hero h1 {
  font-size: clamp(40px, 6vw, 72px);
  line-height: 1.05;
  font-weight: 700;
  margin: 0 0 18px;
  color: #fff;
  letter-spacing: -0.5px;
}
.hero h1 .accent { color: var(--blue-2); display: block; }
.hero .strap {
  font-size: clamp(17px, 2.1vw, 22px);
  color: var(--ink-dim);
  max-width: 740px;
  margin: 0 auto 36px;
}

/* ---------- Volume grid ---------- */
.vol-grid {
  padding: 56px 0 40px;
}
.vol-grid h2 {
  text-align: center;
  font-size: 28px;
  margin: 0 0 8px;
  color: #fff;
}
.vol-grid .sub {
  text-align: center;
  color: var(--ink-dim);
  margin: 0 0 44px;
}
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
}
.card {
  background: var(--navy-2);
  border: 1px solid var(--rule);
  border-radius: 14px;
  padding: 26px 22px;
  transition: transform 0.18s ease, border-color 0.18s ease, background 0.18s ease;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 220px;
  color: inherit;
}
.card:hover {
  transform: translateY(-3px);
  border-color: var(--blue);
  background: var(--navy-3);
}
.card .vnum {
  font-size: 13px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--blue-2);
  font-weight: 600;
  margin-bottom: 10px;
}
.card .vtitle {
  font-size: 19px;
  color: #fff;
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: 16px;
}
.card .vstats {
  font-size: 13px;
  color: var(--ink-dim);
  margin-top: auto;
}
.card .vstats span { color: #fff; font-weight: 600; }

/* ---------- Section generic ---------- */
section {
  padding: 72px 0;
  border-top: 1px solid var(--rule);
}
section h2 {
  font-size: 30px;
  margin: 0 0 16px;
  color: #fff;
}
section h3 {
  font-size: 19px;
  color: #fff;
  margin: 28px 0 10px;
}
section p { color: var(--ink-dim); }
section p strong { color: #fff; }

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}
@media (max-width: 760px) { .two-col { grid-template-columns: 1fr; } }

/* ---------- Stats strip ---------- */
.stats-strip {
  background: var(--navy-2);
  padding: 48px 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}
.stats-strip .row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}
@media (max-width: 680px) { .stats-strip .row { grid-template-columns: repeat(2, 1fr); } }
.stat .n {
  font-size: 36px;
  font-weight: 700;
  color: var(--blue-2);
  line-height: 1;
}
.stat .l {
  margin-top: 8px;
  font-size: 13px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--ink-dim);
}

/* ---------- Email capture ---------- */
.capture {
  padding: 64px 0 80px;
  text-align: center;
}
.capture h2 { margin-bottom: 10px; }
.capture p { color: var(--ink-dim); margin-bottom: 28px; }
.capture form {
  display: flex;
  max-width: 520px;
  margin: 0 auto;
  gap: 10px;
}
.capture input[type="email"] {
  flex: 1;
  padding: 14px 16px;
  font-size: 16px;
  background: var(--navy-2);
  border: 1px solid var(--rule);
  border-radius: 10px;
  color: #fff;
  outline: none;
}
.capture input[type="email"]:focus { border-color: var(--blue); }
.capture button, .btn {
  padding: 14px 24px;
  font-size: 15px;
  font-weight: 600;
  background: var(--blue);
  color: #fff;
  border: 0;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.15s ease;
  text-decoration: none;
  display: inline-block;
}
.capture button:hover, .btn:hover { background: var(--blue-2); color: #fff; }
.btn-outline {
  background: transparent;
  border: 1px solid var(--blue);
  color: var(--blue-2);
}
.btn-outline:hover { background: var(--blue); color: #fff; }
.cta-row { text-align: center; margin-top: 28px; }
.cta-row .btn { margin: 4px; }

/* ---------- Volume detail pages ---------- */
.vol-hero {
  padding: 64px 0 32px;
  background: linear-gradient(180deg, var(--navy-2), var(--navy));
}
.vol-hero .eyebrow {
  letter-spacing: 3px;
  text-transform: uppercase;
  font-size: 13px;
  color: var(--blue-2);
  font-weight: 600;
}
.vol-hero h1 {
  font-size: clamp(32px, 5vw, 52px);
  margin: 8px 0 16px;
  color: #fff;
  line-height: 1.1;
}
.vol-hero .blurb {
  font-size: 18px;
  color: var(--ink-dim);
  max-width: 720px;
}
.spec-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  margin: 32px 0 0;
}
@media (max-width: 680px) { .spec-row { grid-template-columns: repeat(2, 1fr); } }
.spec {
  background: var(--navy-2);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 16px 18px;
}
.spec .lbl { font-size: 12px; letter-spacing: 1.5px; text-transform: uppercase; color: var(--ink-dim); }
.spec .val { font-size: 22px; font-weight: 700; color: #fff; margin-top: 4px; }

.toc-preview {
  columns: 2;
  column-gap: 32px;
  margin-top: 16px;
}
@media (max-width: 680px) { .toc-preview { columns: 1; } }
.toc-preview li {
  break-inside: avoid;
  margin-bottom: 8px;
  color: var(--ink-dim);
  font-size: 15px;
}
.toc-preview li::marker { color: var(--blue); }

.price-box {
  background: var(--navy-2);
  border: 1px solid var(--rule);
  border-radius: 14px;
  padding: 28px;
  display: flex;
  gap: 28px;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}
.price-box .px .amt { font-size: 32px; font-weight: 700; color: #fff; }
.price-box .px .lbl { color: var(--ink-dim); font-size: 13px; letter-spacing: 1.5px; text-transform: uppercase; margin-top: 4px; }

/* ---------- Register page ---------- */
.reg-form {
  max-width: 620px;
  margin: 24px auto 0;
  background: var(--navy-2);
  border: 1px solid var(--rule);
  border-radius: 14px;
  padding: 32px;
}
.reg-form label {
  display: block;
  font-size: 13px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--ink-dim);
  margin: 18px 0 6px;
}
.reg-form input[type="text"],
.reg-form input[type="email"],
.reg-form select,
.reg-form textarea {
  width: 100%;
  padding: 12px 14px;
  background: var(--navy);
  border: 1px solid var(--rule);
  border-radius: 8px;
  color: #fff;
  font-size: 15px;
  font-family: inherit;
  outline: none;
}
.reg-form input:focus, .reg-form select:focus, .reg-form textarea:focus {
  border-color: var(--blue);
}
.reg-form .checks {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
@media (max-width: 520px) { .reg-form .checks { grid-template-columns: 1fr; } }
.reg-form .checks label {
  display: flex;
  align-items: center;
  gap: 10px;
  text-transform: none;
  letter-spacing: 0;
  font-size: 15px;
  color: var(--ink);
  margin: 0;
  padding: 10px 12px;
  background: var(--navy);
  border: 1px solid var(--rule);
  border-radius: 8px;
  cursor: pointer;
}
.reg-form .checks input { accent-color: var(--blue); }
.reg-form button { margin-top: 22px; width: 100%; padding: 16px; font-size: 16px; }

/* ---------- Cover showcase (homepage) ---------- */
.covers-showcase {
  padding: 72px 0 40px;
  background: linear-gradient(180deg, var(--navy-2) 0%, var(--navy) 100%);
  border-top: 1px solid var(--rule);
}
.covers-showcase h2 { text-align: center; margin-bottom: 8px; }
.covers-showcase .sub { text-align: center; color: var(--ink-dim); margin-bottom: 40px; }
.covers-row {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 22px;
  perspective: 1200px;
}
@media (max-width: 900px) { .covers-row { grid-template-columns: repeat(3, 1fr); } }
@media (max-width: 560px) { .covers-row { grid-template-columns: repeat(2, 1fr); } }
.cover-link {
  display: block;
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 14px 40px rgba(0,0,0,0.55), 0 2px 6px rgba(0,0,0,0.35);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  background: #000;
}
.cover-link img { display: block; width: 100%; height: auto; }
.cover-link:hover {
  transform: translateY(-6px) rotateY(-3deg);
  box-shadow: 0 22px 50px rgba(0,0,0,0.65), 0 4px 10px rgba(0,0,0,0.4);
}

/* ---------- Volume-page hero with cover ---------- */
.vol-hero-with-cover {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 36px;
  align-items: center;
}
@media (max-width: 680px) {
  .vol-hero-with-cover { grid-template-columns: 1fr; justify-items: center; text-align: center; }
  .vol-hero-with-cover .vol-copy { text-align: left; }
}
.vol-hero-cover {
  max-width: 220px;
  border-radius: 6px;
  box-shadow: 0 18px 50px rgba(0,0,0,0.6), 0 3px 8px rgba(0,0,0,0.4);
  display: block;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--rule);
  padding: 36px 0 48px;
  color: var(--ink-dim);
  font-size: 14px;
}
.site-footer .row {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
}
.site-footer a { color: var(--ink-dim); margin-left: 20px; }
.site-footer a:first-child { margin-left: 0; }
.site-footer a:hover { color: #fff; }

/* ---------- Utilities ---------- */
.center { text-align: center; }
.muted { color: var(--ink-dim); }
.small { font-size: 13px; }
.mt-0 { margin-top: 0; }
.mt-2 { margin-top: 16px; }
.mt-4 { margin-top: 32px; }
.badge {
  display: inline-block;
  padding: 4px 10px;
  background: rgba(47,130,200,0.18);
  color: var(--blue-2);
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
}