/* ============================================
   binaryconverter.org — unified stylesheet
   Shared by all tool pages
   ============================================ */

:root {
  --bg-page: #f8fafc;
  --bg-subtle: #f1f5f9;
  --bg-card: #ffffff;
  --bg-card-alt: #f8fafc;
  --border: #e2e8f0;
  --border-strong: #cbd5e1;
  --accent: #0284c7;
  --accent-strong: #0369a1;
  --accent-soft: rgba(2, 132, 199, 0.1);
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-inverted: #ffffff;
  --error: #dc2626;
  --shadow-card: 0 1px 3px 0 rgba(15, 23, 42, 0.05);
  --shadow-soft: 0 10px 30px rgba(15, 23, 42, 0.06);

  --radius-xs: 8px;
  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg-page);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

main {
  padding-bottom: 32px;
}

.container {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 20px;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 0.7em;
  color: var(--text-primary);
  line-height: 1.2;
  letter-spacing: -0.025em;
}

p {
  margin: 0 0 1em;
  color: var(--text-secondary);
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover,
a:focus-visible {
  text-decoration: none;
}

code {
  color: var(--accent);
  font-family: var(--font-mono);
}

button,
input,
textarea,
select {
  font: inherit;
}

select,
input,
textarea {
  outline: none;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ============================================
   Header
   ============================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1180px;
  margin: 0 auto;
  padding: 16px 20px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: #0f172a;
  font-size: 1.35rem;
  font-weight: 800;
  text-decoration: none;
  letter-spacing: -0.02em;
}

.logo:hover,
.logo:focus-visible {
  color: #0f172a;
  text-decoration: none;
}

.logo span {
  color: #0284c7;
}

.breadcrumb {
  display: none;
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 1.5rem;
  flex-wrap: wrap;
  margin-left: auto;
}

.site-nav a {
  color: var(--text-secondary);
  font-size: 0.96rem;
  font-weight: 600;
  transition: color 0.2s ease;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--accent);
}

.nav-toggle {
  display: none;
}

.nav-toggle-label {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 28px;
  height: 22px;
  cursor: pointer;
}

.nav-toggle-label span {
  display: block;
  height: 2px;
  border-radius: 999px;
  background: var(--text-primary);
}

/* ============================================
   Hero + intro sections
   ============================================ */
.hero {
  text-align: center;
  padding: 60px 20px 24px;
}

.hero h1 {
  font-size: clamp(2.1rem, 5vw, 3.2rem);
  font-weight: 800;
  letter-spacing: -0.045em;
  margin-bottom: 0.8rem;
}

.hero-sub {
  max-width: 660px;
  margin: 0 auto;
  color: var(--text-secondary);
  font-size: 1.08rem;
}

.info-section {
  margin-top: 48px;
}

.info-section h2,
.seo-section h2 {
  font-size: clamp(1.6rem, 2.7vw, 2.1rem);
  font-weight: 750;
  letter-spacing: -0.03em;
  margin-bottom: 0.75rem;
}

.code-block {
  margin-top: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.92rem;
  line-height: 1.7;
  box-shadow: var(--shadow-card);
}

/* ============================================
   Converter card
   ============================================ */
.converter-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 24px;
  box-shadow: var(--shadow-card);
  margin-top: 28px;
}

.panels {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.panel {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.panel-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
}

.panel-head label {
  color: var(--text-primary);
  font-size: 0.88rem;
  font-weight: 700;
}

.char-count {
  color: var(--text-muted);
  font-size: 0.76rem;
  font-family: var(--font-mono);
}

.io-textarea {
  width: 100%;
  min-height: 220px;
  resize: vertical;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 16px 14px;
  font-family: var(--font-mono);
  font-size: 0.92rem;
  line-height: 1.6;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.io-textarea::placeholder {
  color: var(--text-muted);
}

.io-textarea:focus-visible,
select:focus-visible,
.homepage-mode-select:focus-visible,
input:focus-visible,
textarea:focus-visible,
button:focus-visible {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.12);
}

.io-textarea[readonly] {
  background: var(--bg-subtle);
  color: var(--text-primary);
}

.io-textarea.has-error {
  border-color: var(--error);
}

.error-msg {
  min-height: 18px;
  color: var(--error);
  font-size: 0.78rem;
  margin: 0;
}

.controls {
  display: flex;
  gap: 12px;
  margin-top: 20px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 12px 20px;
  border: 1px solid transparent;
  font-size: 0.92rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.2s ease, border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
}

.btn:active {
  transform: translateY(1px) scale(0.99);
}

.btn-primary {
  background: var(--accent);
  color: var(--text-inverted);
  box-shadow: 0 8px 18px rgba(2, 132, 199, 0.2);
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: var(--accent-strong);
  box-shadow: 0 10px 22px rgba(2, 132, 199, 0.24);
}

.btn-ghost {
  background: transparent;
  border-color: var(--border-strong);
  color: var(--text-primary);
}

.btn-ghost:hover,
.btn-ghost:focus-visible {
  background: var(--bg-card-alt);
  border-color: var(--border-strong);
  color: var(--text-primary);
}

.swap-row {
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 6px 0;
}

.swap-btn {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card-alt);
  border: 1px solid var(--border);
  color: var(--accent);
  font-size: 1.1rem;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
}

.swap-btn:hover,
.swap-btn:focus-visible {
  background: var(--accent-soft);
  border-color: var(--accent);
  transform: translateY(-1px);
}

/* ============================================
   Tabs for mode switching
   ============================================ */
.mode-tabs {
  display: flex;
  gap: 6px;
  background: var(--bg-card-alt);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px;
  margin-bottom: 18px;
}

.mode-tabs button {
  flex: 1;
  background: transparent;
  border: 0;
  border-radius: 999px;
  padding: 10px 14px;
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.mode-tabs button.active {
  background: var(--accent);
  color: var(--text-inverted);
  box-shadow: 0 6px 16px rgba(2, 132, 199, 0.16);
}

/* ============================================
   Cards, FAQs, tables, related tools
   ============================================ */
.example-box,
.faq-item,
.tool-link,
.feature-card,
.tool-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
}

.example-box,
.feature-card {
  padding: 20px;
  margin-top: 16px;
}

.ascii-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 16px;
  font-size: 0.94rem;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

.ascii-table th,
.ascii-table td {
  border: 1px solid var(--border);
  padding: 12px 14px;
  text-align: left;
}

.ascii-table th {
  background: var(--bg-subtle);
  color: var(--text-primary);
  font-weight: 700;
}

.ascii-table td {
  color: var(--text-secondary);
}

.faq-item {
  padding: 18px 20px;
  margin-top: 14px;
}

.faq-item h3 {
  margin-bottom: 0.5rem;
  font-size: 1.02rem;
  font-weight: 700;
}

.faq-item p {
  margin: 0;
  color: var(--text-secondary);
  line-height: 1.7;
}

.seo-block {
  overflow-x: auto;
}

.related-tools {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
  margin-top: 18px;
}

.tool-link {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 18px;
  color: var(--text-primary);
  font-weight: 700;
  transition: border-color 0.2s ease, transform 0.15s ease, box-shadow 0.2s ease;
}

.tool-link:hover,
.tool-link:focus-visible {
  border-color: var(--accent);
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.05);
  transform: translateY(-2px);
}

/* ============================================
   Homepage + tool grids
   ============================================ */

.home-hero {
  padding: 54px 20px 24px;
}

.home-hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.3rem);
}

.homepage-widget {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 1.4rem;
  margin-top: 2rem;
  box-shadow: var(--shadow-soft);
}

.homepage-widget-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.4rem;
}

.homepage-widget-top > div {
  min-width: 0;
}

.widget-label {
  display: block;
  margin: 0 0 0.5rem;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.home-select-wrapper {
  width: min(100%, 360px);
}

.homepage-mode-select,
select {
  width: 100%;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.9rem 1.15rem;
  appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, var(--text-secondary) 50%), linear-gradient(135deg, var(--text-secondary) 50%, transparent 50%);
  background-position: calc(100% - 18px) calc(50% - 2px), calc(100% - 12px) calc(50% - 2px);
  background-size: 6px 6px, 6px 6px;
  background-repeat: no-repeat;
}

select option,
.homepage-mode-select option {
  background: var(--bg-card);
  color: var(--text-primary);
}

.homepage-widget-panel {
  display: grid;
  gap: 1rem;
}

.homepage-widget-panel .panel {
  margin: 0;
}

.homepage-widget-panel textarea,
.homepage-widget-panel input {
  width: 100%;
  min-height: 160px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-primary);
  padding: 1rem;
  resize: vertical;
}

.homepage-widget-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.8rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

.homepage-widget-note {
  color: var(--text-secondary);
  font-size: 0.86rem;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
  margin-top: 22px;
}

.tool-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px;
  transition: transform 0.15s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.tool-card:hover,
.tool-card:focus-visible {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 14px 30px rgba(15, 23, 42, 0.06);
}

.tool-card-title {
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1rem;
}

.tool-card-desc {
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.84rem;
}

.tool-card-arrow {
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 700;
  margin-top: 2px;
}

.category-label {
  margin: 42px 0 6px;
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.category-label:first-of-type {
  margin-top: 26px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.feature-card {
  padding: 18px;
}

.feature-card h3 {
  color: var(--text-primary);
  font-size: 1.02rem;
  margin-bottom: 8px;
}

.feature-card p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.tool-info,
.tool-faq {
  margin-top: 42px;
}

.tool-info h2,
.related-tools h2,
.tool-faq h2 {
  font-size: clamp(1.55rem, 3vw, 2.05rem);
  line-height: 1.2;
  letter-spacing: -0.03em;
  margin-bottom: 0.85rem;
}

.tool-info h3 {
  margin-top: 1.6rem;
  margin-bottom: 0.7rem;
  font-size: 1.18rem;
  letter-spacing: -0.02em;
}

.tool-info p {
  margin-bottom: 1rem;
}

.steps {
  margin: 0;
  padding-left: 1.2rem;
  color: var(--text-secondary);
}

.steps li {
  margin-bottom: 0.7rem;
  line-height: 1.7;
}

.related-tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.tool-faq {
  padding-bottom: 12px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 0;
  margin-top: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-card);
}

.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 20px;
  font-weight: 700;
  color: var(--text-primary);
}

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

.faq-item summary::after {
  content: "+";
  float: right;
  color: var(--accent);
  font-size: 1.1rem;
  line-height: 1;
}

.faq-item[open] summary::after {
  content: "–";
}

.faq-item p {
  margin: 0;
  padding: 0 20px 18px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================
   Footer
   ============================================ */
footer {
  background: #f8fafc;
  border-top: 1px solid var(--border);
  margin-top: 60px;
  padding: 42px 0 26px;
}

.footer-container {
  display: grid;
  grid-template-columns: 1.35fr 1fr 1fr;
  gap: 2rem;
  align-items: start;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 20px;
}

.footer-col {
  min-width: 0;
}

.footer-col .logo {
  display: inline-flex;
  margin-bottom: 0.9rem;
  font-size: 1.15rem;
}

.footer-col p,
.footer-col a,
.footer-col li {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.75;
}

.footer-col h4 {
  margin: 0 0 1rem;
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 700;
}

.footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-col li {
  margin-bottom: 0.7rem;
}

.footer-col a {
  transition: color 0.2s ease;
}

.footer-col a:hover,
.footer-col a:focus-visible {
  color: var(--accent);
}

.footer-bottom {
  max-width: 1180px;
  margin: 1.5rem auto 0;
  padding: 1.1rem 20px 0;
  border-top: 1px solid var(--border);
  text-align: center;
}

.footer-bottom p {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.toast {
  position: fixed;
  bottom: 22px;
  left: 50%;
  transform: translateX(-50%) translateY(18px);
  background: var(--accent);
  color: var(--text-inverted);
  padding: 12px 20px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.88rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  z-index: 100;
  box-shadow: 0 8px 18px rgba(2, 132, 199, 0.18);
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
  .panels {
    grid-template-columns: 1fr;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }

  .site-nav {
    gap: 0.85rem 1.2rem;
  }

  .footer-container {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}

@media (max-width: 640px) {
  .header-inner {
    flex-wrap: wrap;
    gap: 12px;
  }

  .site-nav {
    width: 100%;
    justify-content: flex-end;
    margin-left: 0;
  }

  .mode-tabs {
    flex-direction: column;
    border-radius: var(--radius-md);
  }

  .controls {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .related-tools {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .nav-toggle {
    display: block;
    position: absolute;
    opacity: 0;
    width: 40px;
    height: 40px;
    right: 20px;
    cursor: pointer;
  }

  .nav-toggle-label {
    display: flex;
  }

  .nav-toggle:checked + .nav-toggle-label + .site-nav {
    display: flex;
  }
}

@media (max-width: 480px) {
  .tool-grid,
  .related-tools {
    grid-template-columns: 1fr;
  }

  .homepage-widget {
    padding: 1rem;
  }

  .homepage-widget-top {
    align-items: stretch;
  }
}