/* ── Reset & variables ─────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary:       #2563EB;
  --primary-dark:  #1D4ED8;
  --primary-light: #EFF6FF;
  --accent:        #7C3AED;
  --success:       #059669;
  --success-bg:    #ECFDF5;
  --danger:        #DC2626;
  --danger-bg:     #FEF2F2;
  --warning:       #D97706;
  --warning-bg:    #FFFBEB;
  --info:          #0284C7;
  --info-bg:       #F0F9FF;

  --text:          #1E293B;
  --text-muted:    #64748B;
  --border:        #E2E8F0;
  --bg:            #F8FAFC;
  --card:          #FFFFFF;
  --header-bg:     #0F172A;

  --radius:        8px;
  --radius-lg:     12px;
  --shadow-sm:     0 1px 3px rgba(0,0,0,.08);
  --shadow:        0 4px 12px rgba(0,0,0,.10);
  --shadow-lg:     0 8px 24px rgba(0,0,0,.12);

  --font:          'Inter', system-ui, -apple-system, sans-serif;
  --mono:          'JetBrains Mono', 'Fira Code', monospace;
  --transition:    150ms ease;
}

html { scroll-behavior: smooth; }
body  { font-family: var(--font); background: var(--bg); color: var(--text);
        font-size: 15px; line-height: 1.6; }

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; }

/* ── Typography ────────────────────────────────────────────────────────────── */
h1 { font-size: clamp(1.6rem, 4vw, 2.4rem); font-weight: 700; line-height: 1.2; }
h2 { font-size: 1.4rem; font-weight: 700; }
h3 { font-size: 1.1rem; font-weight: 600; }
h4 { font-size: .95rem; font-weight: 600; }

/* ── Layout helpers ────────────────────────────────────────────────────────── */
.container { max-width: 1160px; margin: 0 auto; padding: 0 20px; }
.section    { padding: 64px 0; }
.section-sm { padding: 32px 0; }

/* ── Header ────────────────────────────────────────────────────────────────── */
.site-header {
  background: var(--header-bg);
  position: sticky; top: 0; z-index: 100;
  border-bottom: 1px solid rgba(255,255,255,.06);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 60px;
}
.logo {
  display: flex; align-items: center; gap: 10px;
  color: #fff; font-size: 1.1rem; font-weight: 700;
  text-decoration: none;
}
.logo svg { flex-shrink: 0; }
.logo span { color: #60A5FA; }

.site-nav { display: flex; align-items: center; gap: 4px; }
.site-nav a {
  color: #CBD5E1; font-size: .875rem; padding: 6px 12px;
  border-radius: var(--radius); transition: background var(--transition), color var(--transition);
  text-decoration: none;
}
.site-nav a:hover { background: rgba(255,255,255,.08); color: #fff; }
.site-nav a.active { color: #fff; background: rgba(255,255,255,.1); }

.nav-divider { width: 1px; height: 20px; background: rgba(255,255,255,.12); margin: 0 6px; }

/* User menu */
.user-menu { position: relative; }
.user-btn {
  display: flex; align-items: center; gap: 8px;
  background: rgba(255,255,255,.1); color: #fff;
  border: none; border-radius: var(--radius); padding: 6px 12px;
  cursor: pointer; font-size: .875rem; font-family: var(--font);
  transition: background var(--transition);
}
.user-btn:hover { background: rgba(255,255,255,.18); }
.user-avatar {
  width: 28px; height: 28px; border-radius: 50%;
  background: var(--primary); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: .75rem; font-weight: 700;
}
.user-dropdown {
  position: absolute; top: calc(100% + 8px); right: 0;
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); box-shadow: var(--shadow-lg);
  min-width: 200px; padding: 6px;
  display: none; z-index: 200;
}
.user-dropdown.open { display: block; }
.user-dropdown a, .user-dropdown button {
  display: flex; align-items: center; gap: 8px;
  padding: 9px 12px; border-radius: var(--radius);
  color: var(--text); font-size: .875rem;
  text-decoration: none; width: 100%; background: none; border: none;
  cursor: pointer; font-family: var(--font); transition: background var(--transition);
}
.user-dropdown a:hover, .user-dropdown button:hover { background: var(--bg); }
.user-dropdown hr { border: none; border-top: 1px solid var(--border); margin: 6px 0; }
.user-dropdown .danger { color: var(--danger); }

/* ── Buttons ───────────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 9px 20px; border-radius: var(--radius);
  font-size: .875rem; font-weight: 600; font-family: var(--font);
  cursor: pointer; border: none; transition: all var(--transition);
  text-decoration: none; white-space: nowrap;
}
.btn:disabled { opacity: .5; cursor: not-allowed; }

.btn-primary   { background: var(--primary); color: #fff; }
.btn-primary:hover:not(:disabled)   { background: var(--primary-dark); text-decoration: none; }
.btn-secondary { background: var(--bg); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover:not(:disabled) { background: var(--border); text-decoration: none; }
.btn-danger    { background: var(--danger); color: #fff; }
.btn-danger:hover:not(:disabled)    { background: #B91C1C; text-decoration: none; }
.btn-ghost     { background: none; color: var(--primary); }
.btn-ghost:hover:not(:disabled)     { background: var(--primary-light); text-decoration: none; }
.btn-sm  { padding: 6px 14px; font-size: .8rem; }
.btn-lg  { padding: 12px 28px; font-size: 1rem; }
.btn-full { width: 100%; justify-content: center; }

/* ── Forms ─────────────────────────────────────────────────────────────────── */
.form-group { display: flex; flex-direction: column; gap: 6px; }
label { font-size: .875rem; font-weight: 500; color: var(--text); }
.input, .textarea, .select {
  width: 100%; padding: 10px 14px;
  border: 1px solid var(--border); border-radius: var(--radius);
  font-size: .9rem; font-family: var(--font); background: var(--card);
  color: var(--text); transition: border-color var(--transition), box-shadow var(--transition);
}
.input:focus, .textarea:focus, .select:focus {
  outline: none; border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,.15);
}
.textarea { resize: vertical; min-height: 100px; font-family: var(--mono); font-size: .85rem; }
.select { 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 fill='%2364748B' d='M6 8L1 3h10z'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 12px center; padding-right: 36px; }
.input-hint { font-size: .8rem; color: var(--text-muted); }
.input-error { font-size: .8rem; color: var(--danger); }
.input.error, .textarea.error { border-color: var(--danger); }

.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 600px) { .form-row { grid-template-columns: 1fr; } }

/* Radio / checkbox groups */
.radio-group { display: flex; gap: 16px; flex-wrap: wrap; }
.radio-label  { display: flex; align-items: center; gap: 6px; cursor: pointer; font-size: .875rem; }

/* ── Cards ─────────────────────────────────────────────────────────────────── */
.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); box-shadow: var(--shadow-sm);
}
.card-body { padding: 24px; }
.card-header {
  padding: 16px 24px; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; justify-content: space-between;
}
.card-footer {
  padding: 16px 24px; border-top: 1px solid var(--border);
  background: var(--bg); border-radius: 0 0 var(--radius-lg) var(--radius-lg);
}

/* ── Badges ────────────────────────────────────────────────────────────────── */
.badge {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 3px 10px; border-radius: 99px;
  font-size: .75rem; font-weight: 600;
}
.badge-success { background: var(--success-bg); color: var(--success); }
.badge-danger  { background: var(--danger-bg);  color: var(--danger); }
.badge-warning { background: var(--warning-bg); color: var(--warning); }
.badge-info    { background: var(--info-bg);    color: var(--info); }
.badge-primary { background: var(--primary-light); color: var(--primary); }

/* ── Alerts ────────────────────────────────────────────────────────────────── */
.alert {
  padding: 14px 16px; border-radius: var(--radius);
  font-size: .875rem; display: flex; gap: 10px; align-items: flex-start;
}
.alert-success { background: var(--success-bg); color: var(--success); border: 1px solid #A7F3D0; }
.alert-error   { background: var(--danger-bg);  color: var(--danger);  border: 1px solid #FECACA; }
.alert-warning { background: var(--warning-bg); color: var(--warning); border: 1px solid #FDE68A; }
.alert-info    { background: var(--info-bg);    color: var(--info);    border: 1px solid #BAE6FD; }

/* ── Tables ────────────────────────────────────────────────────────────────── */
.table-wrap { overflow-x: auto; border-radius: var(--radius); border: 1px solid var(--border); }
table { width: 100%; border-collapse: collapse; font-size: .875rem; }
thead th {
  background: var(--bg); padding: 10px 16px;
  text-align: left; font-weight: 600; font-size: .8rem;
  color: var(--text-muted); text-transform: uppercase; letter-spacing: .04em;
  border-bottom: 1px solid var(--border);
}
tbody td { padding: 10px 16px; border-bottom: 1px solid var(--border); }
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: var(--bg); }
.num { font-family: var(--mono); }

/* ── Spinner ───────────────────────────────────────────────────────────────── */
.spinner {
  display: inline-block; width: 18px; height: 18px;
  border: 2px solid rgba(255,255,255,.3);
  border-top-color: #fff; border-radius: 50%;
  animation: spin .6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Ad slots ──────────────────────────────────────────────────────────────── */
.ad-slot {
  background: #F1F5F9; border: 1px dashed #CBD5E1;
  border-radius: var(--radius); display: flex; align-items: center;
  justify-content: center; color: var(--text-muted); font-size: .75rem;
  font-weight: 500; text-transform: uppercase; letter-spacing: .06em;
  overflow: hidden;
}
.ad-leaderboard { width: 100%; height: 90px; }
.ad-rectangle   { width: 100%; height: 250px; }
.ad-in-content  { width: 100%; height: 100px; margin: 24px 0; }

/* ── Hero ──────────────────────────────────────────────────────────────────── */
.hero {
  background: linear-gradient(135deg, #0F172A 0%, #1E3A5F 100%);
  color: #fff; padding: 80px 0 72px;
}
.hero h1 { color: #fff; margin-bottom: 16px; }
.hero p   { color: #94A3B8; font-size: 1.05rem; max-width: 560px; margin-bottom: 32px; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; }

.hero-stats {
  display: flex; gap: 40px; margin-top: 48px; flex-wrap: wrap;
}
.hero-stat-val { font-size: 1.8rem; font-weight: 700; color: #60A5FA; }
.hero-stat-lbl { font-size: .8rem; color: #94A3B8; margin-top: 2px; }

/* ── Tools grid ────────────────────────────────────────────────────────────── */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}
.tool-card {
  display: flex; flex-direction: column;
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 20px;
  transition: box-shadow var(--transition), border-color var(--transition), transform var(--transition);
  text-decoration: none; color: var(--text);
}
.tool-card:hover {
  box-shadow: var(--shadow); border-color: var(--primary);
  transform: translateY(-2px); text-decoration: none;
}
.tool-icon {
  width: 44px; height: 44px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.3rem; margin-bottom: 14px;
}
.tool-card h3 { font-size: .95rem; margin-bottom: 6px; }
.tool-card p  { font-size: .8rem; color: var(--text-muted); flex: 1; }
.tool-card-arrow {
  margin-top: 16px; font-size: .8rem; font-weight: 600;
  color: var(--primary); display: flex; align-items: center; gap: 4px;
}

/* ── Category section ──────────────────────────────────────────────────────── */
.category-label {
  font-size: .8rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: .06em; color: var(--text-muted);
  display: flex; align-items: center; gap: 8px; margin-bottom: 16px;
}
.category-label::after { content:''; flex: 1; height: 1px; background: var(--border); }

/* ── Tool page layout ──────────────────────────────────────────────────────── */
.page-header {
  background: var(--header-bg); color: #fff; padding: 36px 0;
}
.page-header h1 { font-size: 1.7rem; color: #fff; margin-bottom: 8px; }
.page-header p  { color: #94A3B8; }
.breadcrumb { font-size: .8rem; color: #64748B; margin-bottom: 12px; }
.breadcrumb a { color: #60A5FA; text-decoration: none; }

.tool-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 28px;
  align-items: start;
}
@media (max-width: 900px) {
  .tool-layout { grid-template-columns: 1fr; }
  .tool-sidebar { order: -1; }
}

.tool-sidebar { display: flex; flex-direction: column; gap: 20px; }

/* ── Results section ───────────────────────────────────────────────────────── */
.results-section { margin-top: 24px; }
.results-section.hidden { display: none; }

.result-highlight {
  background: var(--primary-light); border: 1px solid #BFDBFE;
  border-radius: var(--radius-lg); padding: 20px 24px;
  margin-bottom: 20px;
}
.result-highlight .label { font-size: .8rem; color: var(--primary); font-weight: 600; text-transform: uppercase; letter-spacing: .05em; }
.result-highlight .value { font-family: var(--mono); font-size: 1.5rem; font-weight: 700; color: var(--primary-dark); }

.result-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 12px; margin-bottom: 20px;
}
.result-item {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 14px 16px;
}
.result-item .r-label { font-size: .75rem; color: var(--text-muted); font-weight: 500; margin-bottom: 4px; }
.result-item .r-value { font-family: var(--mono); font-size: 1rem; font-weight: 700; color: var(--text); }

.conclusion-box {
  border-radius: var(--radius-lg); padding: 18px 20px;
  display: flex; align-items: flex-start; gap: 14px;
}
.conclusion-box.significant   { background: var(--success-bg); border: 1px solid #6EE7B7; }
.conclusion-box.insignificant { background: #FFF7ED; border: 1px solid #FCD34D; }
.conclusion-icon { font-size: 1.4rem; }
.conclusion-text strong { display: block; font-size: .95rem; margin-bottom: 4px; }
.conclusion-text p { font-size: .875rem; color: var(--text-muted); }

/* ── Chart wrapper ─────────────────────────────────────────────────────────── */
.chart-wrap {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 20px; margin-top: 20px;
}
.chart-wrap h4 { margin-bottom: 16px; color: var(--text-muted); font-size: .8rem;
                 text-transform: uppercase; letter-spacing: .05em; }

/* ── Save button ───────────────────────────────────────────────────────────── */
.save-row {
  display: flex; align-items: center; gap: 12px;
  margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--border);
}
.save-hint { font-size: .8rem; color: var(--text-muted); }

/* ── Auth pages ────────────────────────────────────────────────────────────── */
.auth-page {
  min-height: calc(100vh - 60px);
  display: flex; align-items: center; justify-content: center;
  padding: 32px 20px;
}
.auth-card { width: 100%; max-width: 420px; }
.auth-card .card-body { padding: 32px; }
.auth-logo  { text-align: center; margin-bottom: 28px; }
.auth-logo a { font-size: 1.2rem; font-weight: 800; color: var(--text); }
.auth-logo span { color: var(--primary); }
.auth-title { font-size: 1.4rem; font-weight: 700; margin-bottom: 6px; }
.auth-sub   { color: var(--text-muted); font-size: .875rem; margin-bottom: 28px; }
.auth-form  { display: flex; flex-direction: column; gap: 18px; }
.auth-footer { text-align: center; margin-top: 20px; font-size: .875rem; color: var(--text-muted); }
.auth-footer a { color: var(--primary); font-weight: 500; }

/* Password strength bar */
.strength-bar { height: 4px; border-radius: 2px; background: var(--border); overflow: hidden; margin-top: 6px; }
.strength-fill { height: 100%; border-radius: 2px; transition: width .3s, background .3s; }
.strength-text { font-size: .75rem; margin-top: 4px; }

/* ── Dashboard ─────────────────────────────────────────────────────────────── */
.dashboard-layout {
  display: grid; grid-template-columns: 240px 1fr; gap: 28px; align-items: start;
}
@media (max-width: 800px) { .dashboard-layout { grid-template-columns: 1fr; } }

.dash-nav { display: flex; flex-direction: column; gap: 4px; }
.dash-nav a {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 14px; border-radius: var(--radius);
  color: var(--text-muted); font-size: .875rem; text-decoration: none;
  transition: background var(--transition), color var(--transition);
}
.dash-nav a:hover  { background: var(--bg); color: var(--text); }
.dash-nav a.active { background: var(--primary-light); color: var(--primary); font-weight: 600; }

.history-list { display: flex; flex-direction: column; gap: 12px; }
.history-item {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 16px 20px;
  display: flex; align-items: flex-start; gap: 14px;
}
.history-icon {
  width: 38px; height: 38px; border-radius: 8px;
  background: var(--primary-light); color: var(--primary);
  display: flex; align-items: center; justify-content: center; font-size: 1.1rem;
  flex-shrink: 0;
}
.history-body { flex: 1; min-width: 0; }
.history-tool { font-weight: 600; font-size: .9rem; }
.history-summary { font-size: .8rem; color: var(--text-muted); margin-top: 2px; }
.history-result { font-size: .8rem; color: var(--text); margin-top: 4px; font-family: var(--mono); }
.history-date { font-size: .75rem; color: var(--text-muted); margin-top: 6px; }
.history-actions { display: flex; gap: 6px; margin-left: auto; flex-shrink: 0; }

.empty-state {
  text-align: center; padding: 60px 20px;
  color: var(--text-muted);
}
.empty-state .icon { font-size: 3rem; margin-bottom: 12px; }
.empty-state h3 { font-size: 1rem; color: var(--text); margin-bottom: 8px; }
.empty-state p  { font-size: .875rem; }

/* ── Pagination ────────────────────────────────────────────────────────────── */
.pagination {
  display: flex; align-items: center; gap: 8px; margin-top: 20px;
  justify-content: center;
}
.page-btn {
  width: 36px; height: 36px; border: 1px solid var(--border);
  border-radius: var(--radius); background: var(--card); cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: .875rem; color: var(--text); font-family: var(--font);
  transition: all var(--transition);
}
.page-btn:hover:not(:disabled) { border-color: var(--primary); color: var(--primary); }
.page-btn.active { background: var(--primary); border-color: var(--primary); color: #fff; }
.page-btn:disabled { opacity: .4; cursor: not-allowed; }

/* ── Tabs ──────────────────────────────────────────────────────────────────── */
.tabs { display: flex; border-bottom: 2px solid var(--border); margin-bottom: 24px; gap: 0; }
.tab-btn {
  padding: 10px 18px; cursor: pointer; border: none; background: none;
  font-family: var(--font); font-size: .875rem; color: var(--text-muted);
  border-bottom: 2px solid transparent; margin-bottom: -2px;
  transition: color var(--transition), border-color var(--transition);
}
.tab-btn.active { color: var(--primary); border-bottom-color: var(--primary); font-weight: 600; }
.tab-btn:hover:not(.active) { color: var(--text); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ── Section headings ──────────────────────────────────────────────────────── */
.section-title {
  font-size: 1.5rem; font-weight: 700; margin-bottom: 8px;
}
.section-sub  { color: var(--text-muted); margin-bottom: 36px; }

/* ── Footer ────────────────────────────────────────────────────────────────── */
.site-footer {
  background: var(--header-bg); color: #94A3B8;
  padding: 48px 0 32px; margin-top: 80px;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr;
  gap: 40px; margin-bottom: 40px;
}
@media (max-width: 700px) { .footer-grid { grid-template-columns: 1fr; } }
.footer-brand { max-width: 280px; }
.footer-brand .logo { margin-bottom: 12px; }
.footer-brand p { font-size: .875rem; line-height: 1.7; }
.footer-links h4 { color: #fff; font-size: .875rem; margin-bottom: 14px; }
.footer-links ul { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.footer-links a { color: #94A3B8; font-size: .875rem; text-decoration: none; transition: color var(--transition); }
.footer-links a:hover { color: #fff; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08);
  padding-top: 24px; display: flex; justify-content: space-between;
  align-items: center; font-size: .8rem; flex-wrap: wrap; gap: 8px;
}

/* ── Related tools ─────────────────────────────────────────────────────────── */
.related-tools { display: flex; flex-wrap: wrap; gap: 10px; }
.related-chip {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: 99px;
  border: 1px solid var(--border); background: var(--card);
  color: var(--text); font-size: .8rem; text-decoration: none;
  transition: all var(--transition);
}
.related-chip:hover { border-color: var(--primary); color: var(--primary); text-decoration: none; }

/* ── Utility ───────────────────────────────────────────────────────────────── */
.text-muted  { color: var(--text-muted); }
.text-sm     { font-size: .875rem; }
.text-xs     { font-size: .75rem; }
.text-center { text-align: center; }
.mono        { font-family: var(--mono); }
.gap-8  { gap: 8px; }
.gap-12 { gap: 12px; }
.gap-16 { gap: 16px; }
.gap-24 { gap: 24px; }
.flex   { display: flex; }
.flex-col { display: flex; flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.mt-4  { margin-top: 4px; }
.mt-8  { margin-top: 8px; }
.mt-12 { margin-top: 12px; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mb-4  { margin-bottom: 4px; }
.mb-8  { margin-bottom: 8px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }
.hidden { display: none !important; }

/* ── Responsive ────────────────────────────────────────────────────────────── */
@media (max-width: 640px) {
  .result-grid { grid-template-columns: 1fr 1fr; }
  .hero { padding: 48px 0 40px; }
  .hero-stats { gap: 24px; }
  .section { padding: 40px 0; }
  .card-body { padding: 16px; }
}

/* ── Tooltip ───────────────────────────────────────────────────────────────── */
[data-tip] { position: relative; cursor: help; }
[data-tip]::after {
  content: attr(data-tip);
  position: absolute; bottom: calc(100% + 6px); left: 50%; transform: translateX(-50%);
  background: #1E293B; color: #fff; border-radius: 6px;
  padding: 6px 10px; font-size: .75rem; white-space: nowrap; z-index: 10;
  pointer-events: none; opacity: 0; transition: opacity .15s;
}
[data-tip]:hover::after { opacity: 1; }

/* ── FAQ accordion ─────────────────────────────────────────────────────────── */
.faq { display: flex; flex-direction: column; gap: 8px; }
.faq-item { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.faq-q {
  width: 100%; background: none; border: none; cursor: pointer;
  padding: 14px 16px; text-align: left; font-family: var(--font);
  font-size: .9rem; font-weight: 600; color: var(--text);
  display: flex; justify-content: space-between; align-items: center;
  transition: background var(--transition);
}
.faq-q:hover { background: var(--bg); }
.faq-q .arrow { font-size: .7rem; transition: transform .2s; }
.faq-q.open .arrow { transform: rotate(180deg); }
.faq-a { padding: 0 16px; max-height: 0; overflow: hidden; transition: max-height .25s, padding .25s; }
.faq-a.open { padding: 0 16px 14px; max-height: 400px; }
.faq-a p { font-size: .875rem; color: var(--text-muted); }

/* ── Guide FAQ (new pattern) ────────────────────────────────────────────────── */
.faq-accordion { display: flex; flex-direction: column; gap: 8px; }
.faq-question {
  width: 100%; background: none; border: 1px solid var(--border); border-radius: var(--radius);
  cursor: pointer; padding: 14px 18px; text-align: left; font-family: var(--font);
  font-size: .925rem; font-weight: 600; color: var(--text);
  transition: background var(--transition), border-color var(--transition);
  display: flex; justify-content: space-between; align-items: center;
}
.faq-question::after { content: '▼'; font-size: .65rem; transition: transform .2s; flex-shrink:0; margin-left:8px; }
.faq-question:hover { background: var(--bg-hover, #F1F5F9); border-color: var(--primary); }
.faq-question.open { background: var(--primary); color: #fff; border-color: var(--primary); border-bottom-left-radius:0; border-bottom-right-radius:0; }
.faq-question.open::after { transform: rotate(180deg); }
.faq-answer {
  padding: 0 18px; max-height: 0; overflow: hidden;
  transition: max-height .3s ease, padding .3s ease;
  border: 1px solid var(--border); border-top: none;
  border-bottom-left-radius: var(--radius); border-bottom-right-radius: var(--radius);
  background: var(--surface);
}
.faq-answer.open { padding: 16px 18px 18px; max-height: 600px; }
.faq-answer p, .faq-answer li { font-size: .875rem; color: var(--text-muted); line-height: 1.7; }
.faq-answer p + p { margin-top: 10px; }
.faq-answer ul { padding-left: 20px; margin-top: 8px; }
.mt-32 { margin-top: 2rem; }

.result-item.highlight .r-value { color: var(--primary); }

/* ── Article / guide prose ──────────────────────────────────────────────── */
.article { max-width: 760px; margin: 0 auto; }
.article p { color: var(--text-muted); line-height: 1.85; margin-bottom: 16px; }
.article h2 { margin: 36px 0 14px; font-size: 1.45rem; }
.article h3 { margin: 26px 0 10px; font-size: 1.1rem; }
.article ul, .article ol { color: var(--text-muted); line-height: 1.9; padding-left: 22px; margin-bottom: 16px; }
.article li { margin-bottom: 6px; }
.article a { color: var(--primary); }
.article strong { color: var(--text); }
.article code { font-family: var(--mono); background: var(--info-bg); padding: 2px 6px; border-radius: 5px; font-size: .9em; }
.article .callout {
  border-left: 4px solid var(--primary); background: var(--info-bg);
  padding: 14px 18px; border-radius: 8px; margin: 20px 0;
}
.article .callout p:last-child { margin-bottom: 0; }
.article table { width: 100%; border-collapse: collapse; margin: 18px 0; font-size: .92rem; }
.article th, .article td { border: 1px solid var(--border); padding: 9px 12px; text-align: left; }
.article th { background: var(--info-bg); font-weight: 600; }
.guide-cta {
  display: block; border: 1px solid var(--primary); background: var(--primary-light);
  border-radius: var(--radius); padding: 16px 20px; margin: 22px 0; text-decoration: none;
  color: var(--text); font-weight: 600; transition: var(--transition);
}
.guide-cta:hover { background: var(--primary); color: #fff; }
.guide-cta span { display: block; font-weight: 400; font-size: .85rem; color: var(--text-muted); margin-top: 4px; }
.guide-cta:hover span { color: rgba(255,255,255,.85); }
.guide-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 640px) { .guide-grid { grid-template-columns: 1fr; } }

/* ── Dark mode ───────────────────────────────────────────────────────────── */
:root[data-theme="dark"] {
  --primary-light:#172554;
  --success-bg:#062a26; --danger-bg:#3b1a1a; --warning-bg:#3a2a10; --info-bg:#0b2a3d;
  --text:#e5ecf5; --text-muted:#94a3b8; --border:#26344a;
  --bg:#0b1120; --card:#111c33; --header-bg:#0b1120;
  --shadow-sm:0 1px 3px rgba(0,0,0,.5); --shadow:0 4px 12px rgba(0,0,0,.55); --shadow-lg:0 10px 28px rgba(0,0,0,.6);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --primary-light:#172554;
    --success-bg:#062a26; --danger-bg:#3b1a1a; --warning-bg:#3a2a10; --info-bg:#0b2a3d;
    --text:#e5ecf5; --text-muted:#94a3b8; --border:#26344a;
    --bg:#0b1120; --card:#111c33; --header-bg:#0b1120;
    --shadow-sm:0 1px 3px rgba(0,0,0,.5); --shadow:0 4px 12px rgba(0,0,0,.55); --shadow-lg:0 10px 28px rgba(0,0,0,.6);
  }
}
html { color-scheme: light dark; }
:root[data-theme="dark"] { color-scheme: dark; }
:root[data-theme="light"] { color-scheme: light; }

/* Theme toggle button (injected into the nav) */
.theme-toggle {
  display:inline-flex; align-items:center; justify-content:center;
  width:34px; height:34px; border-radius:8px; cursor:pointer;
  background:transparent; border:1px solid rgba(255,255,255,.18); color:#e5ecf5;
  font-size:1rem; line-height:1; transition:var(--transition); padding:0;
}
.theme-toggle:hover { background:rgba(255,255,255,.10); }

/* Load-example button (injected next to Calculate) */
.btn-example {
  background:transparent; border:1px dashed var(--border); color:var(--text-muted);
  border-radius:var(--radius); padding:9px 16px; font-size:.85rem; font-weight:600;
  cursor:pointer; font-family:var(--font); transition:var(--transition); margin-left:10px;
}
.btn-example:hover { border-color:var(--primary); color:var(--primary); border-style:solid; }

/* Copy-results button (injected atop results) */
.copy-results-bar { display:flex; justify-content:flex-end; margin-bottom:10px; }
.btn-copy {
  display:inline-flex; align-items:center; gap:6px;
  background:var(--card); border:1px solid var(--border); color:var(--text-muted);
  border-radius:var(--radius); padding:7px 13px; font-size:.82rem; font-weight:600;
  cursor:pointer; font-family:var(--font); transition:var(--transition);
}
.btn-copy:hover { border-color:var(--primary); color:var(--primary); }
.btn-copy.copied { border-color:var(--success); color:var(--success); }

/* Homepage tool search/filter */
.tool-search-wrap { max-width:520px; margin:0 auto 28px; position:relative; }
.tool-search {
  width:100%; padding:13px 18px 13px 44px; font-size:1rem; font-family:var(--font);
  border:1px solid var(--border); border-radius:999px; background:var(--card); color:var(--text);
  box-shadow:var(--shadow-sm); transition:var(--transition);
}
.tool-search:focus { outline:none; border-color:var(--primary); box-shadow:0 0 0 3px rgba(37,99,235,.15); }
.tool-search-wrap::before {
  content:'🔍'; position:absolute; left:16px; top:50%; transform:translateY(-50%);
  font-size:.95rem; opacity:.6; pointer-events:none;
}
.tools-no-match { text-align:center; color:var(--text-muted); padding:24px; display:none; }

/* ── Form polish + style classless inputs on newer tool pages (2026-08) ─────── */
.input, .textarea, .select,
.form-group input:not([type=checkbox]):not([type=radio]),
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 15px;
  font-size: .95rem;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  border: 1.5px solid var(--border);
  border-radius: 10px;
  transition: border-color var(--transition), box-shadow var(--transition), background var(--transition);
  -webkit-appearance: none; appearance: none;
}
.form-group input:not([type=checkbox]):not([type=radio]) { height: 46px; }
.input:hover:not(:focus), .textarea:hover:not(:focus), .select:hover:not(:focus),
.form-group input:hover:not(:focus):not([type=checkbox]):not([type=radio]),
.form-group textarea:hover:not(:focus),
.form-group select:hover:not(:focus) { border-color: var(--text-muted); }
.input:focus, .textarea:focus, .select:focus,
.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
  outline: none;
  background: var(--card);
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(37,99,235,.13);
}
.input::placeholder, .textarea::placeholder,
.form-group input::placeholder, .form-group textarea::placeholder { color: var(--text-muted); opacity: .6; }

/* comfortable textareas, keep mono for data legibility */
.textarea, .form-group textarea {
  min-height: 104px; line-height: 1.6; font-family: var(--mono); font-size: .875rem; resize: vertical;
}

/* stronger, clearer labels */
.form-group label, label {
  font-size: .8rem; font-weight: 600; color: var(--text);
  letter-spacing: .01em; margin-bottom: 2px;
}

/* remove number spinners for a clean field */
.form-group input[type=number]::-webkit-outer-spin-button,
.form-group input[type=number]::-webkit-inner-spin-button,
input[type=number]::-webkit-outer-spin-button,
input[type=number]::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
input[type=number] { -moz-appearance: textfield; }

/* custom select caret (also for classless selects) */
.form-group select, .select {
  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 fill='%2394a3b8' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 14px center; padding-right: 40px; cursor: pointer;
}

/* give the calculate button breathing room + full width on narrow forms */
.card-body .btn-primary.btn-lg { margin-top: 6px; }
@media (max-width: 560px) { .card-body .btn-primary.btn-lg { width: 100%; justify-content: center; } }

/* ── Statistical tables (z/t/chi-square/F) ──────────────────────────────────── */
.stat-table { border-collapse: collapse; font-family: var(--mono); font-size: .82rem; min-width: 560px; }
.stat-table th, .stat-table td { border: 1px solid var(--border); padding: 6px 9px; text-align: center; white-space: nowrap; }
.stat-table thead th { position: sticky; top: 0; background: var(--primary); color: #fff; z-index: 2; font-family: var(--font); font-weight: 600; }
.stat-table tbody th { position: sticky; left: 0; background: var(--card); font-weight: 700; }
.stat-table tbody tr:nth-child(even) td { background: var(--bg); }
.stat-table tbody tr:hover td, .stat-table tbody tr:hover th { background: var(--primary-light); }