/* ============================================
   Components
   ============================================ */

/* -------- Header / Nav -------- */
.site-header {
  border-bottom: 1.5px solid var(--border);
  padding: var(--space-4) var(--space-5);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 50;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.02em;
  text-decoration: none;
}
.site-logo:hover { text-decoration: none; }
.site-nav {
  display: flex;
  gap: var(--space-6);
  font-size: 13px;
  font-weight: 500;
}
.site-nav a { transition: opacity 0.15s; }
.site-nav a.active { border-bottom: 1.5px solid var(--text); }
.site-nav a:hover { text-decoration: none; opacity: 0.6; }

.menu-toggle {
  display: none;
  background: none;
  border: 1.5px solid var(--border);
  padding: 6px 10px;
  cursor: pointer;
}

@media (max-width: 760px) {
  .site-nav {
    position: absolute;
    top: 100%; left: 0; right: 0;
    background: var(--bg);
    border-bottom: 1.5px solid var(--border);
    flex-direction: column;
    gap: 0;
    padding: var(--space-3) var(--space-5);
    display: none;
  }
  .site-nav.open { display: flex; }
  .site-nav a { padding: var(--space-3) 0; border-bottom: 1px solid var(--border-soft); }
  .menu-toggle { display: inline-flex; }
}

/* -------- Footer -------- */
.site-footer {
  border-top: 1.5px solid var(--border);
  background: var(--bg-inverse);
  color: var(--text-inverse);
  padding: var(--space-6) var(--space-5);
}
.footer-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr 1fr;
  gap: var(--space-6);
}
.footer-col h4 {
  font-size: 11px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  opacity: 0.5;
  margin: 0 0 var(--space-3);
  font-family: var(--font-body);
  font-weight: 600;
}
.footer-col ul { list-style: none; padding: 0; margin: 0; }
.footer-col li { margin-bottom: var(--space-2); font-size: 14px; opacity: 0.85; }
.footer-bottom {
  max-width: var(--container-max);
  margin: var(--space-6) auto 0;
  padding-top: var(--space-5);
  border-top: 1px solid rgba(245,241,232,0.15);
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  opacity: 0.6;
  flex-wrap: wrap;
  gap: var(--space-3);
}
@media (max-width: 760px) {
  .footer-inner { grid-template-columns: 1fr 1fr; }
}

/* -------- Buttons -------- */
.btn {
  padding: 10px 18px;
  background: var(--bg-inverse);
  color: var(--text-inverse);
  border: 1.5px solid var(--border);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  transition: all 0.12s;
  text-decoration: none;
}
.btn:hover {
  background: var(--bg);
  color: var(--text);
  text-decoration: none;
}
.btn-outline { background: transparent; color: var(--text); }
.btn-outline:hover { background: var(--bg-inverse); color: var(--text-inverse); }
.btn-accent { background: var(--accent); border-color: var(--accent); }
.btn-accent:hover { background: var(--bg); color: var(--accent); }

.btn-icon { padding: 10px 12px; }
.btn-large { padding: 14px 24px; font-size: 14px; }

/* -------- Inputs -------- */
.input-field {
  width: 100%;
  padding: 14px 16px;
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  font-size: 22px;
  font-family: var(--font-mono);
  font-weight: 500;
  outline: none;
  transition: all 0.15s;
}
.input-field:focus {
  background: #fffbef;
  box-shadow: 3px 3px 0 var(--border);
  transform: translate(-1px, -1px);
}
.input-field.error { border-color: var(--error); background: var(--error-bg); }

.input-small {
  padding: 8px 10px;
  font-size: 15px;
}

.unit-select {
  width: 100%;
  padding: 10px 12px;
  background: var(--bg-elevated);
  border: 1.5px solid var(--border);
  border-top: none;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  outline: none;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M2 4L6 8L10 4' stroke='%231a1a1a' stroke-width='1.5' fill='none'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 32px;
}
.unit-select-standalone {
  border-top: 1.5px solid var(--border);
}

.field-label {
  display: block;
  font-size: 11px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 6px;
}

/* -------- Cards / Result blocks -------- */
.result-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  padding: var(--space-4) var(--space-5);
  position: relative;
}
.result-card:hover .copy-btn { opacity: 1; }

.result-card-large {
  background: var(--bg-inverse);
  color: var(--text-inverse);
  padding: var(--space-6) var(--space-5);
  border: 1.5px solid var(--border);
  position: relative;
}

.copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--text-subtle);
  opacity: 0;
  transition: opacity 0.15s, color 0.15s;
  padding: 4px;
  display: inline-flex;
}
.copy-btn:hover { color: var(--text); }
.copy-btn.always-on { opacity: 1; color: #a8a08c; }
.copy-btn.always-on:hover { color: var(--text-inverse); }

/* -------- Hero -------- */
.hero {
  padding: var(--space-8) var(--space-5) var(--space-5);
  max-width: var(--container-max);
  margin: 0 auto;
}
.hero h1 em {
  font-style: italic;
  color: var(--accent);
}
.hero-lead {
  font-size: 17px;
  color: var(--text-muted);
  max-width: 580px;
  line-height: 1.55;
}

/* -------- Calculator layout -------- */
.calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-7);
  align-items: start;
}
.dim-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}
.action-row {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
  align-items: center;
}
.action-tip {
  font-size: 12px;
  color: var(--text-subtle);
}

@media (max-width: 760px) {
  .calc-grid { grid-template-columns: 1fr; gap: var(--space-6); }
  .dim-grid { grid-template-columns: 1fr; }
}

/* -------- 3D preview frame -------- */
.preview-frame {
  background: var(--bg-elevated);
  border: 1.5px solid var(--border);
  padding: var(--space-6) var(--space-4) var(--space-2);
  position: relative;
}
.preview-frame-label {
  position: absolute;
  top: 12px;
  left: 16px;
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.preview-dims {
  display: flex;
  justify-content: space-around;
  font-size: 11px;
  color: var(--text-muted);
  padding-bottom: var(--space-3);
  font-family: var(--font-mono);
}

/* -------- Volume display -------- */
.volume-main {
  margin-bottom: var(--space-4);
}
.volume-main-value {
  font-family: var(--font-display);
  font-size: 56px;
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1;
}
.volume-main-unit {
  font-size: 13px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-top: var(--space-2);
  opacity: 0.7;
}
.volume-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}
.volume-card-label {
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-subtle);
  margin-bottom: var(--space-1);
}
.volume-card-value {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 500;
  letter-spacing: -0.02em;
}
.volume-card-unit {
  font-size: 13px;
  color: var(--text-subtle);
  margin-left: 6px;
  font-family: var(--font-mono);
}
.volume-card-sub {
  font-size: 11px;
  color: #999;
  margin-top: var(--space-1);
  font-family: var(--font-mono);
}

.text-link {
  background: none;
  border: none;
  text-decoration: underline;
  font-size: 13px;
  cursor: pointer;
  color: var(--text-muted);
  padding: 0;
  text-underline-offset: 3px;
}

/* -------- Formula section -------- */
.formula-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  padding: var(--space-6) var(--space-5);
}
.formula-expr {
  font-family: var(--font-display);
  font-size: 48px;
  font-weight: 500;
  text-align: center;
  letter-spacing: -0.02em;
  padding: var(--space-5) 0;
}
.formula-divider {
  border: none;
  border-top: 1px solid var(--border-soft);
  margin: var(--space-5) 0;
}
.code-block {
  font-family: var(--font-mono);
  font-size: 15px;
  line-height: 1.8;
  background: var(--bg);
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--border-soft);
}

/* -------- FAQ -------- */
.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: var(--space-4) 0;
  font-size: 18px;
  font-weight: 500;
  border-bottom: 1px solid var(--border-soft);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 24px; font-weight: 300; }
.faq-item[open] summary::after { content: "−"; }
.faq-item[open] summary { border-bottom-color: var(--border); }
.faq-content {
  padding: var(--space-4) 0 var(--space-5);
  color: var(--text-muted);
  line-height: 1.65;
}

/* -------- Shipping page -------- */
.carrier-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}
.carrier-btn {
  padding: var(--space-3) var(--space-3);
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  cursor: pointer;
  text-align: left;
  transition: all 0.12s;
  font-family: inherit;
}
.carrier-btn:hover { background: var(--bg-elevated); }
.carrier-btn.active {
  background: var(--bg-inverse);
  color: var(--text-inverse);
}
.carrier-name {
  font-weight: 600;
  font-size: 14px;
  margin-bottom: 2px;
}
.carrier-meta {
  font-size: 11px;
  opacity: 0.7;
  font-family: var(--font-mono);
}

.warning-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: #fff5f4;
  color: var(--error);
  border: 1.5px solid var(--error);
  padding: 6px 12px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-top: var(--space-3);
}

/* -------- Batch / table -------- */
.batch-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  margin-bottom: var(--space-4);
}
.batch-table th, .batch-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border-soft);
  text-align: left;
  font-size: 14px;
}
.batch-table th {
  background: var(--bg-elevated);
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
}
.batch-table tr:last-child td { border-bottom: none; }
.batch-table input, .batch-table select {
  width: 100%;
  background: transparent;
  border: 1px solid transparent;
  padding: 6px 8px;
  font-family: var(--font-mono);
  font-size: 14px;
  outline: none;
}
.batch-table input:focus, .batch-table select:focus {
  background: #fffbef;
  border-color: var(--border);
}
.batch-table .col-num {
  font-family: var(--font-mono);
  text-align: right;
  font-weight: 500;
}
.batch-row-actions { display: flex; gap: 4px; }
.icon-btn {
  background: none;
  border: 1px solid transparent;
  cursor: pointer;
  padding: 4px 6px;
  color: var(--text-subtle);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.icon-btn:hover { color: var(--error); border-color: var(--border-soft); }

.batch-totals {
  background: var(--bg-inverse);
  color: var(--text-inverse);
  padding: var(--space-5);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--space-4);
}
.batch-total-item .label {
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  opacity: 0.6;
  margin-bottom: 4px;
}
.batch-total-item .value {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 500;
}

/* -------- Misc -------- */
.preset-row {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin-bottom: var(--space-4);
}
.preset-chip {
  padding: 6px 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  font-size: 12px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.12s;
}
.preset-chip:hover { background: var(--bg-inverse); color: var(--text-inverse); }

.empty-state {
  height: 240px;
  display: grid;
  place-items: center;
  color: var(--text-subtle);
  font-size: 14px;
}

.use-case-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: var(--space-4);
}
.use-case-card {
  border: 1.5px solid var(--border);
  padding: var(--space-5);
  background: var(--bg-card);
  transition: all 0.15s;
}
.use-case-card:hover {
  background: var(--bg-elevated);
  transform: translate(-2px, -2px);
  box-shadow: 4px 4px 0 var(--border);
}
.use-case-card h3 { margin-bottom: var(--space-2); }
.use-case-card p { font-size: 14px; color: var(--text-muted); margin: 0; }

/* ============================================================
   Ad banner — placed below nav, above page content
   ============================================================ */
.ad-banner {
  width: 100%;
  display: flex;
  justify-content: center;
  background: var(--bg-elevated, #ede5d3);
  border-bottom: 1px solid var(--border);
  padding: 8px 16px;
  min-height: 50px;
}
.ad-banner-inner {
  display: flex;
  justify-content: center;
  align-items: center;
}
/* Desktop banner (728x90) — show only on screens wide enough */
.ad-banner-inner.desktop {
  width: 728px;
  max-width: 100%;
  min-height: 90px;
}
.ad-banner-inner.mobile {
  display: none;
  width: 320px;
  min-height: 50px;
}
@media (max-width: 760px) {
  .ad-banner-inner.desktop { display: none; }
  .ad-banner-inner.mobile { display: flex; }
  .ad-banner { min-height: 50px; padding: 6px 8px; }
}
/* Don't print ads */
@media print {
  .ad-banner { display: none; }
}

/* View toggle buttons (single carrier / compare) */
.view-toggle-btn {
  transition: background 0.15s ease, color 0.15s ease;
}
.view-toggle-btn:hover {
  background: var(--bg-elevated) !important;
}
.view-toggle-btn.active {
  background: var(--text) !important;
  color: var(--bg) !important;
}