@import url('https://fonts.googleapis.com/css2?family=Inter:ital,wght@0,400;0,500;0,600;0,700;1,400&display=swap');

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:            #F7F4EF;
  --surface:       #FFFFFF;
  --surface-warm:  #FDF8F2;
  --border:        #E5DDD0;
  --border-light:  #EDE8E0;
  --text:          #1C1917;
  --text-2:        #6B6460;
  --text-3:        #A09890;
  --accent:        #C96A1A;
  --accent-hover:  #A8561A;
  --accent-light:  #FEF0E0;
  --accent-subtle: #FDF6EE;
  --green:         #166534;
  --green-bg:      #F0FDF4;
  --green-border:  #BBF7D0;
  --shadow-sm:     0 1px 3px rgba(60,40,20,0.08);
  --shadow-md:     0 4px 12px rgba(60,40,20,0.10);
  --shadow-lg:     0 8px 24px rgba(60,40,20,0.12);
  --radius:        12px;
  --radius-sm:     8px;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* ── HEADER ── */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 32px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 9px;
  text-decoration: none;
  flex-shrink: 0;
}
.logo-icon {
  width: 34px;
  height: 34px;
  background: var(--accent);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 17px;
  font-weight: 700;
}
.logo-text {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.3px;
}
.logo-text span { color: var(--accent); }

nav {
  display: flex;
  gap: 4px;
  flex: 1;
}
nav a {
  text-decoration: none;
  color: var(--text-2);
  font-size: 14px;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: 6px;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}
nav a:hover { background: var(--bg); color: var(--text); }
nav a.active { background: var(--accent-light); color: var(--accent); font-weight: 600; }

.header-search {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 7px 12px;
  cursor: text;
  min-width: 180px;
  flex-shrink: 0;
}
.header-search svg { color: var(--text-3); flex-shrink: 0; }
.header-search span { font-size: 14px; color: var(--text-3); }

/* ── AD SLOTS ── */
.ad-slot {
  background: repeating-linear-gradient(
    45deg,
    #F0EBE3,
    #F0EBE3 4px,
    #EDE7DE 4px,
    #EDE7DE 8px
  );
  border: 2px dashed #C9BAA8;
  border-radius: var(--radius-sm);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: #9C8C7C;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  gap: 4px;
}
.ad-slot .ad-size { font-size: 11px; font-weight: 400; opacity: 0.7; }

.ad-leaderboard {
  max-width: 1200px;
  margin: 16px auto 0;
  padding: 0 24px;
}
.ad-leaderboard .ad-slot { width: 100%; height: 90px; }

.sidebar-ad .ad-slot { width: 100%; height: 250px; }
.below-ad .ad-slot { width: 100%; height: 90px; }
.below-ad { margin-top: 24px; }

/* ── PAGE LAYOUT ── */
.page-wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 24px 60px;
}

/* ── BREADCRUMB ── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--text-3);
  margin-bottom: 20px;
}
.breadcrumb a { text-decoration: none; color: var(--accent); }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb-sep { color: var(--border); }

/* ── PAGE HEADER ── */
.page-header { margin-bottom: 28px; }
.page-header h1 {
  font-size: 30px;
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--text);
  margin-bottom: 6px;
}
.page-header p { color: var(--text-2); font-size: 15px; max-width: 520px; }

/* ── HUB INDEX ── */
.hub-intro { margin-bottom: 36px; }
.hub-intro h1 { font-size: 28px; font-weight: 700; letter-spacing: -0.4px; margin-bottom: 8px; }
.hub-intro p { color: var(--text-2); font-size: 15px; }

.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  margin-bottom: 48px;
}
.hub-card {
  display: block;
  text-decoration: none;
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 22px 24px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.15s, transform 0.15s, border-color 0.15s;
  position: relative;
  overflow: hidden;
}
.hub-card::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--accent);
  opacity: 0;
  transition: opacity 0.15s;
}
.hub-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--accent);
}
.hub-card:hover::before { opacity: 1; }
.hub-card-icon { font-size: 28px; margin-bottom: 14px; }
.hub-card h3 { font-size: 16px; font-weight: 600; color: var(--text); margin-bottom: 6px; line-height: 1.3; }
.hub-card p { font-size: 14px; color: var(--text-2); line-height: 1.5; margin-bottom: 14px; }
.hub-card-link { font-size: 13px; font-weight: 600; color: var(--accent); }

/* ── CALCULATOR TWO-COLUMN GRID ── */
.calc-grid {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 24px;
  align-items: start;
}

/* ── CARD ── */
.card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}
.card-header {
  padding: 20px 24px 16px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  gap: 10px;
}
.card-icon {
  width: 32px;
  height: 32px;
  background: var(--accent-light);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
}
.card-header h2 { font-size: 16px; font-weight: 600; color: var(--text); }
.card-body { padding: 24px; }

/* ── FORM ELEMENTS ── */
.field { margin-bottom: 20px; }
.field:last-of-type { margin-bottom: 0; }
label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-2);
  margin-bottom: 8px;
}
select, input[type="number"], textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: 'Inter', sans-serif;
  font-size: 15px;
  color: var(--text);
  background: var(--surface-warm);
  appearance: none;
  -webkit-appearance: none;
  transition: border-color 0.15s, box-shadow 0.15s;
  outline: none;
}
select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23A09890' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 36px;
}
textarea { resize: vertical; min-height: 100px; line-height: 1.6; }
select:focus, input:focus, textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(201,106,26,0.12);
}
input[type="text"], input[type="email"] {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: 'Inter', sans-serif;
  font-size: 15px;
  color: var(--text);
  background: var(--surface-warm);
  transition: border-color 0.15s, box-shadow 0.15s;
  outline: none;
}
input[type="text"]:focus, input[type="email"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(201,106,26,0.12);
}
.field-hint { font-size: 12px; color: var(--text-3); margin-top: 5px; line-height: 1.5; }

.input-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.input-row .field { margin-bottom: 0; }

.input-with-unit { position: relative; }
.input-with-unit input { padding-right: 48px; }
.input-unit {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 13px;
  color: var(--text-3);
  pointer-events: none;
}

.toggle-group { display: flex; gap: 8px; flex-wrap: wrap; }
.toggle-btn {
  flex: 1;
  min-width: 60px;
  padding: 9px 10px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-warm);
  font-family: 'Inter', sans-serif;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-2);
  cursor: pointer;
  transition: all 0.15s;
  text-align: center;
}
.toggle-btn:hover { border-color: var(--accent); color: var(--accent); }
.toggle-btn.active {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

.btn-calculate {
  width: 100%;
  margin-top: 24px;
  padding: 13px;
  background: var(--accent);
  color: white;
  font-family: 'Inter', sans-serif;
  font-size: 15px;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.15s, transform 0.1s, box-shadow 0.15s;
  box-shadow: 0 2px 8px rgba(201,106,26,0.30);
  letter-spacing: -0.1px;
}
.btn-calculate:hover { background: var(--accent-hover); box-shadow: 0 4px 12px rgba(201,106,26,0.35); }
.btn-calculate:active { transform: translateY(1px); }

/* ── SIDEBAR ── */
.sidebar { display: flex; flex-direction: column; gap: 20px; position: sticky; top: 76px; }

/* ── RESULT HERO ── */
.result-hero {
  background: var(--green-bg);
  border: 1px solid var(--green-border);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
}
.result-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--green);
  opacity: 0.7;
  margin-bottom: 4px;
}
.result-number {
  font-size: 52px;
  font-weight: 700;
  color: var(--green);
  letter-spacing: -2px;
  line-height: 1;
  margin-bottom: 4px;
}
.result-number-md {
  font-size: 34px;
  letter-spacing: -1px;
}
.result-unit { font-size: 14px; color: var(--green); opacity: 0.7; margin-bottom: 16px; }
.result-placeholder { padding: 20px 0 10px; }
.result-placeholder-icon { font-size: 36px; margin-bottom: 8px; }
.result-placeholder p { font-size: 14px; color: var(--text-3); font-style: italic; }

.result-table { width: 100%; border-collapse: collapse; margin-top: 4px; }
.result-table tr { border-top: 1px solid var(--green-border); }
.result-table td { padding: 9px 0; font-size: 13px; }
.result-table td:last-child { text-align: right; font-weight: 600; color: var(--green); }
.result-table td:first-child { color: var(--text-2); text-align: left; }

.tip-box {
  background: var(--accent-subtle);
  border: 1px solid #F5D9BC;
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  font-size: 13px;
  color: var(--accent-hover);
  text-align: left;
  margin-top: 16px;
  line-height: 1.55;
  display: none;
}
.tip-box strong { display: block; margin-bottom: 3px; font-weight: 600; }

/* ── RELATED SECTION ── */
.section-title {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text);
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
.related-card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 18px;
  text-decoration: none;
  color: inherit;
  transition: box-shadow 0.15s, transform 0.15s, border-color 0.15s;
  display: block;
}
.related-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--accent);
}
.related-card .rc-icon { font-size: 24px; margin-bottom: 10px; }
.related-card .rc-name { font-size: 14px; font-weight: 600; margin-bottom: 4px; color: var(--text); }
.related-card .rc-desc { font-size: 12px; color: var(--text-2); }

/* ── CONTENT / SEO ── */
.content-section { margin-top: 56px; }
.content-section h2 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 12px;
  margin-top: 32px;
  color: var(--text);
}
.content-section h2:first-child { margin-top: 0; }
.content-section p { color: var(--text-2); margin-bottom: 14px; line-height: 1.75; }
.content-section ul { padding-left: 20px; color: var(--text-2); margin-bottom: 14px; }
.content-section li { margin-bottom: 8px; line-height: 1.6; }
.content-section strong { color: var(--text); }

.faq { margin-top: 48px; }
.faq-title { font-size: 20px; font-weight: 700; margin-bottom: 4px; color: var(--text); }
.faq-item { border-bottom: 1px solid var(--border-light); padding: 20px 0; }
.faq-item:first-of-type { border-top: 1px solid var(--border-light); margin-top: 16px; }
.faq-item h3 { font-size: 15px; font-weight: 600; margin-bottom: 8px; color: var(--text); }
.faq-item p { color: var(--text-2); font-size: 14px; line-height: 1.65; }

/* ── FOOTER ── */
footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 28px 24px;
  margin-top: 60px;
}
.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}
.footer-left { font-size: 13px; color: var(--text-3); }
.footer-links { display: flex; gap: 20px; }
.footer-links a { font-size: 13px; color: var(--text-3); text-decoration: none; }
.footer-links a:hover { color: var(--accent); }

/* ── RESPONSIVE ── */
@media (max-width: 860px) {
  .calc-grid { grid-template-columns: 1fr; }
  .sidebar { position: static; }
  .related-grid { grid-template-columns: 1fr 1fr; }
  .hub-grid { grid-template-columns: 1fr 1fr; }
  nav a:not(.active) { display: none; }
  .header-search { display: none; }
}
@media (max-width: 520px) {
  .hub-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }
  .input-row { grid-template-columns: 1fr; }
  .page-header h1 { font-size: 24px; }
}