/* ===================================================================
   Base64Lab — folha de estilos principal
   =================================================================== */

:root {
  --bg: #F8FAFC;
  --bg-secondary: #EFF6FF;
  --surface: #FFFFFF;
  --primary: #2563EB;
  --primary-hover: #1D4ED8;
  --primary-light: #60A5FA;
  --text: #1E293B;
  --text-light: #64748B;
  --border: #CBD5E1;
  --success: #22C55E;
  --warning: #F59E0B;
  --danger: #EF4444;

  --font-display: 'Space Grotesk', 'Segoe UI', sans-serif;
  --font-body: 'Inter', 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;

  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 2px rgba(30, 41, 59, 0.06);
  --shadow: 0 4px 16px rgba(37, 99, 235, 0.08);
  --shadow-lg: 0 12px 32px rgba(37, 99, 235, 0.14);
  --maxw: 1180px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
  border-radius: 4px;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--text);
  margin: 0 0 .5em 0;
  letter-spacing: -0.01em;
}

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

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

.mono { font-family: var(--font-mono); }

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  text-transform: uppercase;
  color: var(--primary);
  background: var(--bg-secondary);
  border: 1px solid var(--primary-light);
  padding: 5px 12px;
  border-radius: 999px;
}

/* ---------------------------- Header ---------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(248, 250, 252, 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 19px;
  color: var(--text);
}

.brand .mark {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 13px;
  box-shadow: var(--shadow);
}

.brand small {
  display: block;
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 11px;
  color: var(--text-light);
  letter-spacing: .02em;
}

.main-nav { display: flex; align-items: center; gap: 28px; }

.main-nav a {
  color: var(--text-light);
  font-size: 14.5px;
  font-weight: 500;
}
.main-nav a:hover { color: var(--primary); }
.main-nav a.active { color: var(--primary); }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after {
  content: '';
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text);
  position: relative;
  transition: transform .2s ease;
}
.nav-toggle span::before { position: absolute; top: -6px; }
.nav-toggle span::after { position: absolute; top: 6px; }

/* ------------------------------ Hero ------------------------------ */

.hero {
  padding: 56px 0 8px;
}

.hero-top {
  display: flex;
  flex-direction: column;
  gap: 14px;
  max-width: 720px;
  margin-bottom: 40px;
}

.hero h1 {
  font-size: clamp(30px, 4vw, 44px);
  line-height: 1.08;
}

.hero h1 .accent { color: var(--primary); }

.hero p.lead {
  font-size: 16.5px;
  max-width: 60ch;
}

/* --------------------------- Converter --------------------------- */

.converter {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.converter-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-secondary);
}

.mode-switch {
  display: inline-flex;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
  gap: 2px;
}

.mode-switch button {
  border: none;
  background: transparent;
  padding: 8px 18px;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .02em;
  color: var(--text-light);
  cursor: pointer;
  transition: background .15s ease, color .15s ease;
}

.mode-switch button.active {
  background: var(--primary);
  color: #fff;
}

.toolbar-options {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.opt {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--text-light);
  cursor: pointer;
  user-select: none;
}

.opt input { accent-color: var(--primary); width: 15px; height: 15px; }

.converter-body {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: stretch;
}

.panel {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
}

.panel-head .label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--text-light);
}

.panel-head .counter {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-light);
}

.panel textarea {
  flex: 1;
  min-height: 260px;
  resize: vertical;
  border: none;
  outline: none;
  background: transparent;
  padding: 0 20px 20px;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.55;
  color: var(--text);
}

.panel textarea::placeholder { color: #A6B2C2; }

.divider {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 6px;
  position: relative;
}

.divider::before {
  content: '';
  position: absolute;
  top: 0; bottom: 0; left: 50%;
  width: 1px;
  background: var(--border);
}

.divider .arrow-btn {
  position: relative;
  z-index: 1;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform .15s ease, background .15s ease, color .15s ease;
}

.divider .arrow-btn:hover {
  background: var(--primary);
  color: #fff;
  transform: scale(1.06);
}

.converter-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  padding: 14px 20px;
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.status-msg {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-light);
  display: flex;
  align-items: center;
  gap: 6px;
}
.status-msg.error { color: var(--danger); }
.status-msg .dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--success);
}
.status-msg.error .dot { background: var(--danger); }

.btn-group { display: flex; gap: 8px; flex-wrap: wrap; }

.btn {
  font-family: var(--font-body);
  font-size: 13.5px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  padding: 9px 16px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background .15s ease, border-color .15s ease, color .15s ease, transform .1s ease;
}

.btn:hover { border-color: var(--primary-light); color: var(--primary); }
.btn:active { transform: translateY(1px); }

.btn-primary {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}
.btn-primary:hover { background: var(--primary-hover); border-color: var(--primary-hover); color: #fff; }

.btn-ghost {
  background: transparent;
  border-color: transparent;
  color: var(--text-light);
}
.btn-ghost:hover { color: var(--primary); background: var(--bg-secondary); }

/* ------------------------- File converter ------------------------- */

.file-tool {
  margin-top: 28px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 22px 24px 24px;
}

.file-tool h2 {
  font-size: 18px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.file-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-top: 16px;
}

.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 28px 18px;
  text-align: center;
  cursor: pointer;
  background: var(--bg-secondary);
  transition: border-color .15s ease, background .15s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  min-height: 180px;
  justify-content: center;
}

.dropzone.drag { border-color: var(--primary); background: #E6EEFD; }

.dropzone svg { color: var(--primary); }

.dropzone strong { color: var(--text); font-size: 14.5px; }
.dropzone span { font-size: 12.5px; color: var(--text-light); }

.dropzone input { display: none; }

.file-preview {
  display: none;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  margin-top: 12px;
}

.file-preview.show { display: flex; }

.file-preview img {
  width: 44px; height: 44px;
  object-fit: cover;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
}

.file-preview .fi-icon {
  width: 44px; height: 44px;
  border-radius: 6px;
  background: var(--surface);
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--primary);
  flex-shrink: 0;
}

.file-preview .fi-meta { min-width: 0; flex: 1; }
.file-preview .fi-meta strong {
  display: block;
  font-size: 13.5px;
  color: var(--text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.file-preview .fi-meta span { font-size: 12px; color: var(--text-light); font-family: var(--font-mono); }

.output-col textarea {
  width: 100%;
  min-height: 180px;
  resize: vertical;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-secondary);
  padding: 14px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--text);
}

.output-col .colhead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.output-col .colhead .label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--text-light);
}

/* ------------------------- Signature: mapping ------------------------- */

.mapping-section { padding: 72px 0 20px; }

.mapping-intro { max-width: 640px; margin: 0 auto 32px; text-align: left; }

.mapping-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 24px;
  overflow-x: auto;
}

.mapping-input {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.mapping-input label {
  font-family: var(--font-mono);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-light);
}

.mapping-input input {
  font-family: var(--font-mono);
  font-size: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  width: 220px;
  background: var(--bg-secondary);
  color: var(--text);
}

.byte-groups {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  padding-bottom: 8px;
}

.byte-group {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
  background: var(--bg-secondary);
  min-width: 210px;
}

.byte-group .bg-title {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: .06em;
  margin-bottom: 8px;
}

.byte-row { display: flex; gap: 4px; margin-bottom: 6px; }

.byte-cell {
  flex: 1;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-light);
}

.bit-strip {
  display: flex;
  gap: 2px;
  margin-bottom: 8px;
}

.bit {
  flex: 1;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 12px;
  padding: 5px 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--text);
}

.sextet-strip { display: flex; gap: 4px; }

.sextet {
  flex: 1;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  padding: 8px 4px;
  border-radius: 5px;
  background: var(--primary);
  color: #fff;
}

.sextet.pad { background: var(--text-light); }

/* ------------------------------ Info ------------------------------ */

.info-section { padding: 60px 0; }

.info-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 28px;
}

.info-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow-sm);
}

.info-card .num {
  font-family: var(--font-mono);
  color: var(--primary-light);
  font-size: 26px;
  font-weight: 700;
  margin-bottom: 8px;
}

.info-card h3 { font-size: 16px; margin-bottom: 6px; }
.info-card p { font-size: 14px; margin: 0; }

.faq { max-width: 780px; margin: 40px auto 0; }

.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 18px 0;
}

.faq-item summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-family: var(--font-mono);
  color: var(--primary);
  font-size: 20px;
  flex-shrink: 0;
}
.faq-item[open] summary::after { content: '\2212'; }
.faq-item p { margin-top: 10px; }

/* ------------------------------ Footer ------------------------------ */

.site-footer {
  border-top: 1px solid var(--border);
  background: var(--surface);
  margin-top: 40px;
  padding: 40px 0 28px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 32px;
}

.footer-grid h4 {
  font-family: var(--font-mono);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-light);
  margin-bottom: 12px;
}

.footer-grid ul { list-style: none; margin: 0; padding: 0; }
.footer-grid li { margin-bottom: 8px; }
.footer-grid a { color: var(--text); font-size: 14px; }
.footer-grid a:hover { color: var(--primary); }

.footer-bottom {
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 13px;
  color: var(--text-light);
}

/* ------------------------------ Ad rail ------------------------------ */

.ad-slot {
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  background: var(--bg-secondary);
  color: var(--text-light);
  font-family: var(--font-mono);
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: .06em;
  text-align: center;
  padding: 14px;
  margin: 32px 0;
}

/* ------------------------------ Static pages ------------------------------ */

.page-hero {
  padding: 52px 0 8px;
  max-width: 760px;
}
.page-content { padding: 24px 0 64px; max-width: 760px; }
.page-content h2 { font-size: 20px; margin-top: 32px; }
.page-content ul { color: var(--text-light); padding-left: 20px; }
.page-content li { margin-bottom: 8px; }

/* ------------------------------ Responsive ------------------------------ */

@media (max-width: 880px) {
  .converter-body { grid-template-columns: 1fr; }
  .divider { padding: 10px 0; }
  .divider::before { top: 50%; left: 0; right: 0; width: auto; height: 1px; }
  .divider .arrow-btn { transform: rotate(90deg); }
  .divider .arrow-btn:hover { transform: rotate(90deg) scale(1.06); }
  .file-grid { grid-template-columns: 1fr; }
  .info-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .main-nav { position: fixed; top: 68px; left: 0; right: 0; background: var(--surface); border-bottom: 1px solid var(--border); flex-direction: column; align-items: flex-start; padding: 16px 24px; gap: 14px; display: none; box-shadow: var(--shadow); }
  .main-nav.open { display: flex; }
  .nav-toggle { display: flex; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}