/* Bitcoin Ledger Review - Main Styles */
:root {
  --color1: #12141d;
  --color2: #122f40;
  --color3: #12556a;
  --color4: #17829c;
  --color5: #1fb6d7;
  --bg-light: #f0f7fa;
  --white: #ffffff;
  --text-muted: #5a6b73;
  --border: rgba(31, 182, 215, 0.2);
  --shadow: 0 4px 24px rgba(18, 47, 64, 0.08);
  --shadow-hover: 0 8px 32px rgba(18, 47, 64, 0.12);
  --radius: 12px;
  --radius-lg: 20px;
  --font-main: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --max-width: 1200px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-main);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color1);
  background: var(--white);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.site-header {
  background: linear-gradient(135deg, var(--color2) 0%, var(--color3) 100%);
  color: var(--white);
  padding: 1rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.site-logo {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--white);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.site-logo:hover {
  color: var(--color5);
}

/* Nav */
.main-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
}

.main-nav a {
  color: rgba(255,255,255,0.9);
  text-decoration: none;
  font-weight: 500;
  padding: 0.35rem 0.5rem;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: var(--color5);
  background: rgba(255,255,255,0.1);
}

/* Language switcher */
.lang-switcher {
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.lang-switcher a {
  color: rgba(255,255,255,0.9);
  text-decoration: none;
  font-weight: 500;
  padding: 0.35rem 0.6rem;
  border-radius: 6px;
  font-size: 0.9rem;
  transition: color 0.2s, background 0.2s;
}

.lang-switcher a:hover {
  color: var(--color5);
  background: rgba(255,255,255,0.1);
}

.lang-switcher .current {
  color: var(--color5);
  font-weight: 600;
  pointer-events: none;
}

/* Main content */
main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
  width: 100%;
}

/* Hero / Page title block */
.hero-block {
  background: linear-gradient(160deg, var(--color2) 0%, var(--color3) 50%, var(--color4) 100%);
  color: var(--white);
  padding: 2.5rem 2rem;
  border-radius: var(--radius-lg);
  margin-bottom: 2rem;
  text-align: center;
}

.hero-block h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  line-height: 1.25;
}

.hero-block p {
  margin: 0;
  opacity: 0.95;
  font-size: 1rem;
  max-width: 60ch;
  margin-left: auto;
  margin-right: auto;
}

/* Content blocks */
.content-block {
  margin-bottom: 2.5rem;
}

.content-block h2 {
  color: var(--color2);
  font-size: 1.5rem;
  margin: 0 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color4);
}

.content-block h3 {
  color: var(--color3);
  font-size: 1.2rem;
  margin: 1.5rem 0 0.75rem;
}

.content-block p {
  margin: 0 0 1rem;
  color: var(--color1);
}

.content-block ul,
.content-block ol {
  margin: 0 0 1rem 1.5rem;
  padding: 0;
}

.content-block li {
  margin-bottom: 0.5rem;
}

/* Card / feature blocks */
.card-block {
  background: var(--bg-light);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  transition: box-shadow 0.2s;
}

.card-block:hover {
  box-shadow: var(--shadow-hover);
}

.card-block h3 {
  margin-top: 0;
  color: var(--color3);
}

/* Image blocks - not too large */
.content-img {
  max-width: 100%;
  width: 320px;
  height: auto;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin: 1rem 0;
  display: block;
}

/* Tables */
.table-wrap {
  overflow-x: auto;
  margin: 1rem 0;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.content-block table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.content-block th,
.content-block td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.content-block th {
  background: var(--color2);
  color: var(--white);
  font-weight: 600;
}

.content-block tr:nth-child(even) {
  background: rgba(31, 182, 215, 0.06);
}

/* Internal links in content */
.content-block a {
  color: var(--color4);
  text-decoration: none;
  font-weight: 500;
  border-bottom: 1px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}

.content-block a:hover {
  color: var(--color5);
  border-bottom-color: var(--color5);
}

/* FAQ block */
.faq-block {
  margin-top: 2.5rem;
  padding-top: 2rem;
  border-top: 2px solid var(--border);
}

.faq-block h2 {
  margin-bottom: 1.25rem;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 0.75rem;
  overflow: hidden;
  background: var(--white);
}

.faq-item summary {
  padding: 1rem 1.25rem;
  font-weight: 600;
  color: var(--color2);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  transition: background 0.2s;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.25rem;
  color: var(--color4);
  flex-shrink: 0;
}

.faq-item[open] summary::after {
  content: '−';
}

.faq-item summary:hover {
  background: var(--bg-light);
}

.faq-item .faq-answer {
  padding: 0 1.25rem 1rem;
  color: var(--color1);
  line-height: 1.6;
}

.faq-item .faq-answer p {
  margin: 0 0 0.5rem;
}

/* Footer */
.site-footer {
  background: var(--color1);
  color: rgba(255,255,255,0.85);
  padding: 2rem 1.5rem;
  margin-top: 3rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-menu {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  margin-bottom: 1.5rem;
}

.footer-menu a {
  color: var(--color5);
  text-decoration: none;
  font-weight: 500;
}

.footer-menu a:hover {
  text-decoration: underline;
}

.footer-bottom {
  padding-top: 1rem;
  border-top: 1px solid rgba(255,255,255,0.15);
  font-size: 0.9rem;
  opacity: 0.9;
}

/* Responsive */
@media (max-width: 768px) {
  .site-header {
    padding: 0.75rem 1rem;
  }

  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav ul {
    flex-direction: column;
    gap: 0.25rem;
  }

  main {
    padding: 1.5rem 1rem;
  }

  .hero-block {
    padding: 1.75rem 1.25rem;
  }

  .content-img {
    width: 100%;
    max-width: 320px;
  }
}

@media (min-width: 769px) {
  .content-block .float-img {
    float: right;
    margin-left: 1.5rem;
    margin-bottom: 1rem;
  }

  .content-block::after {
    content: '';
    display: table;
    clear: both;
  }
}