/* ============ CalcNova — core stylesheet ============ */
:root{
  --bg:#f5f7fa; --surface:#ffffff; --surface2:#eef2f7; --text:#17212b; --muted:#5c6b7a;
  --border:#dde4ec; --primary:#0b6ee0; --primary-dark:#0957b3; --primary-soft:#e7f1fd;
  --accent:#0b9e6d; --accent-soft:#e5f6ef; --danger:#c0392b; --radius:14px;
  --shadow:0 1px 3px rgba(23,33,43,.08),0 4px 16px rgba(23,33,43,.06);
  --shadow-lg:0 8px 32px rgba(23,33,43,.14);
  --ad-h:110px; --maxw:1140px;
}
[data-theme="dark"]{
  --bg:#0d1319; --surface:#151d27; --surface2:#1b2530; --text:#e7edf4; --muted:#93a3b3;
  --border:#27313d; --primary:#5aa2ff; --primary-dark:#8abfff; --primary-soft:#12273f;
  --accent:#3ecf9a; --accent-soft:#0f2c23; --danger:#ff7b6b; --shadow:0 1px 3px rgba(0,0,0,.4),0 4px 16px rgba(0,0,0,.3);
  --shadow-lg:0 8px 32px rgba(0,0,0,.5);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  background:var(--bg);color:var(--text);line-height:1.6;font-size:16px;-webkit-font-smoothing:antialiased}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;height:auto}
.container{max-width:var(--maxw);margin:0 auto;padding:0 20px}
h1{font-size:clamp(1.7rem,4vw,2.5rem);line-height:1.2;margin:.3em 0 .4em}
h2{font-size:clamp(1.3rem,3vw,1.8rem);margin:1.4em 0 .5em}
h3{font-size:1.15rem;margin:1.2em 0 .4em}
p{margin:.5em 0}
.muted{color:var(--muted)}
.small{font-size:.875rem}
:focus-visible{outline:3px solid var(--primary);outline-offset:2px;border-radius:4px}

/* ---------- Header ---------- */
.site-header{position:sticky;top:0;z-index:50;background:var(--surface);border-bottom:1px solid var(--border);box-shadow:var(--shadow)}
.header-inner{display:flex;align-items:center;gap:18px;min-height:64px}
.logo{font-size:1.35rem;font-weight:800;color:var(--text);display:flex;align-items:center;gap:8px;letter-spacing:-.02em;white-space:nowrap}
.logo:hover{text-decoration:none}
.logo-mark{display:inline-grid;place-items:center;width:34px;height:34px;border-radius:9px;background:linear-gradient(135deg,var(--primary),#6c3df4);color:#fff;font-size:1rem;font-weight:800}
.main-nav{display:flex;gap:4px;margin-left:8px}
.main-nav a{color:var(--text);font-weight:600;font-size:.95rem;padding:8px 12px;border-radius:8px}
.main-nav a:hover{background:var(--surface2);text-decoration:none}
.header-actions{margin-left:auto;display:flex;align-items:center;gap:10px}
.search-wrap{position:relative}
.search-wrap input{width:220px;padding:9px 14px 9px 36px;border:1px solid var(--border);border-radius:999px;background:var(--surface2);color:var(--text);font-size:.9rem}
.search-wrap::before{content:"";position:absolute;left:13px;top:50%;width:14px;height:14px;transform:translateY(-50%);
  background:currentColor;opacity:.5;-webkit-mask:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2'%3E%3Ccircle cx='11' cy='11' r='7'/%3E%3Cpath d='m21 21-4.3-4.3'/%3E%3C/svg%3E") center/contain no-repeat;
  mask:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2'%3E%3Ccircle cx='11' cy='11' r='7'/%3E%3Cpath d='m21 21-4.3-4.3'/%3E%3C/svg%3E") center/contain no-repeat}
.search-drop{position:absolute;top:calc(100% + 8px);right:0;width:min(360px,86vw);background:var(--surface);border:1px solid var(--border);
  border-radius:12px;box-shadow:var(--shadow-lg);max-height:60vh;overflow:auto;display:none}
.search-drop.open{display:block}
.sr-item{display:flex;flex-direction:column;gap:2px;padding:10px 14px;border-bottom:1px solid var(--border);color:var(--text)}
.sr-item:last-child{border-bottom:0}
.sr-item:hover{background:var(--surface2);text-decoration:none}
.sr-item .sr-cat{font-size:.72rem;text-transform:uppercase;letter-spacing:.06em;color:var(--accent);font-weight:700}
.sr-item .sr-name{font-weight:700;font-size:.95rem}
.sr-item .sr-desc{font-size:.82rem;color:var(--muted);display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden}
.sr-empty{padding:16px;color:var(--muted);text-align:center}
.icon-btn{background:var(--surface2);border:1px solid var(--border);color:var(--text);width:38px;height:38px;border-radius:10px;cursor:pointer;font-size:1.05rem;display:grid;place-items:center}
.icon-btn:hover{background:var(--border)}
.hamburger{display:none}
.mobile-nav{display:none;flex-direction:column;padding:8px 0 14px;border-top:1px solid var(--border)}
.mobile-nav a{padding:11px 6px;color:var(--text);font-weight:600;border-bottom:1px solid var(--surface2)}
@media(max-width:900px){
  .main-nav{display:none}
  .hamburger{display:grid}
  .mobile-nav.open{display:flex}
  .search-wrap input{width:150px}
}
@media(max-width:480px){.search-wrap input{width:110px}}

/* ---------- Hero ---------- */
.hero{padding:64px 0 48px;text-align:center;background:
  radial-gradient(900px 320px at 20% -10%,rgba(11,110,224,.10),transparent),
  radial-gradient(700px 300px at 85% 0%,rgba(108,61,244,.10),transparent)}
.hero p.lead{max-width:640px;margin:0 auto 26px;font-size:1.12rem;color:var(--muted)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 26px;border-radius:12px;border:1px solid transparent;
  font-weight:700;font-size:1rem;cursor:pointer;transition:transform .12s ease,box-shadow .12s ease;text-align:center}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-primary{background:var(--primary);color:#fff;box-shadow:0 4px 14px rgba(11,110,224,.35)}
.btn-primary:hover{background:var(--primary-dark)}
.btn-ghost{background:var(--surface);border-color:var(--border);color:var(--text)}
.btn-ghost:hover{background:var(--surface2)}
.btn-accent{background:var(--accent);color:#fff}
.btn-lg{padding:14px 32px;font-size:1.08rem}
.btn-sm{padding:8px 16px;font-size:.88rem;border-radius:9px}
.badge{display:inline-block;background:var(--primary-soft);color:var(--primary-dark);padding:4px 14px;border-radius:999px;font-size:.8rem;font-weight:700;letter-spacing:.04em}
[data-theme="dark"] .badge{color:var(--primary)}

/* ---------- Sections ---------- */
.section{padding:44px 0}
.section-alt{background:var(--surface);border-top:1px solid var(--border);border-bottom:1px solid var(--border)}
.section-head{max-width:680px;margin:0 auto 30px;text-align:center}
.section-head p{color:var(--muted)}
.grid{display:grid;gap:16px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
@media(max-width:980px){.grid-4{grid-template-columns:repeat(2,1fr)}.grid-3{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}}
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow);transition:transform .15s ease,box-shadow .15s ease}
a.card{color:var(--text);display:block}
a.card:hover{text-decoration:none;transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.card h3{margin:.2em 0 .3em}
.card p{color:var(--muted);font-size:.92rem;margin:0}
.card .cat-icon{width:44px;height:44px;border-radius:11px;background:var(--primary-soft);display:grid;place-items:center;font-size:1.25rem;margin-bottom:10px}
.card .count{font-size:.78rem;font-weight:700;color:var(--accent);text-transform:uppercase;letter-spacing:.05em}
.feature-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:22px}
.feature-card .fi{width:42px;height:42px;border-radius:10px;background:var(--accent-soft);color:var(--accent);display:grid;place-items:center;font-size:1.2rem;margin-bottom:10px}
.step-num{width:36px;height:36px;border-radius:50%;background:var(--primary);color:#fff;display:grid;place-items:center;font-weight:800;margin:0 auto 12px}
.steps{text-align:center}

/* ---------- Ads ---------- */
.ad-slot{margin:34px auto;max-width:var(--maxw);padding:0 20px}
.ad-box{min-height:var(--ad-h);border:1px dashed var(--border);border-radius:12px;background:var(--surface2);
  display:flex;align-items:center;justify-content:center;position:relative}
.ad-box::before{content:"Advertisement";position:absolute;top:6px;left:12px;font-size:.66rem;letter-spacing:.12em;text-transform:uppercase;color:var(--muted)}
.ad-box span{color:var(--muted);font-size:.9rem}
.ad-leaderboard{min-height:110px}
.ad-rect{min-height:250px;max-width:340px}

/* ---------- Breadcrumbs ---------- */
.crumbs{font-size:.85rem;color:var(--muted);margin:18px 0 4px;display:flex;flex-wrap:wrap;gap:6px;align-items:center}
.crumbs a{color:var(--muted)}
.crumbs a:hover{color:var(--primary)}
.crumbs .sep{opacity:.5}

/* ---------- Calculator pages ---------- */
.page-intro{max-width:720px;color:var(--muted)}
.calc-shell{display:grid;grid-template-columns:1fr 320px;gap:26px;align-items:start;margin-top:22px}
@media(max-width:960px){.calc-shell{grid-template-columns:1fr}}
.calc-card-main{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow)}
.calc-form{display:grid;gap:14px}
@media(min-width:560px){.calc-form.cols-2{grid-template-columns:1fr 1fr}}
.field label{display:block;font-weight:600;font-size:.9rem;margin-bottom:5px}
.field .hint{font-size:.78rem;color:var(--muted);font-weight:400}
.field input,.field select,.field textarea{width:100%;padding:11px 13px;border:1px solid var(--border);border-radius:10px;
  background:var(--surface2);color:var(--text);font-size:1rem;font-family:inherit}
.field input:focus,.field select:focus,.field textarea:focus{border-color:var(--primary);outline:none;box-shadow:0 0 0 3px var(--primary-soft)}
.field .f-err{color:var(--danger);font-size:.8rem;min-height:1em;display:block;margin-top:3px}
.form-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:4px}
.calc-error{background:#fdecea;color:var(--danger);border:1px solid #f5c6c0;border-radius:10px;padding:10px 14px;font-size:.92rem;display:none}
[data-theme="dark"] .calc-error{background:#3a1f1c;border-color:#5a322c}
.calc-error.show{display:block}
.results{margin-top:18px;border:1px solid var(--border);border-radius:12px;overflow:hidden;display:none}
.results.show{display:block}
.results-header{background:var(--primary-soft);padding:10px 16px;font-weight:800;color:var(--primary-dark);font-size:.85rem;letter-spacing:.05em;text-transform:uppercase}
[data-theme="dark"] .results-header{color:var(--primary)}
.results table{width:100%;border-collapse:collapse}
.results td{padding:11px 16px;border-bottom:1px solid var(--border);font-size:.95rem}
.results tr:last-child td{border-bottom:0}
.results td.v{text-align:right;font-weight:700;font-variant-numeric:tabular-nums;white-space:nowrap}
.results tr.hl td{background:var(--accent-soft)}
.results-note{padding:10px 16px;font-size:.85rem;color:var(--muted);border-top:1px solid var(--border);background:var(--surface2)}
.side-col{display:flex;flex-direction:column;gap:22px}
.formula-box,.explain-box,.note-box,.example-box{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:18px 20px;margin-top:22px}
.formula-box code{display:block;background:var(--surface2);border-radius:8px;padding:10px 14px;margin-top:8px;font-size:.95rem;overflow-x:auto;white-space:nowrap}
.note-box{border-left:4px solid var(--accent)}
.note-box.warn{border-left-color:#e6a23c;background:#fdf6ec}
[data-theme="dark"] .note-box.warn{background:#33270f}
.disclaimer{background:var(--surface2);border:1px solid var(--border);border-radius:10px;padding:12px 16px;font-size:.82rem;color:var(--muted);margin-top:18px}

/* ---------- FAQ ---------- */
.faq details{border:1px solid var(--border);border-radius:10px;background:var(--surface);margin-bottom:10px}
.faq summary{cursor:pointer;padding:13px 16px;font-weight:700;list-style:none;display:flex;justify-content:space-between;align-items:center;gap:10px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-size:1.3rem;color:var(--muted);flex:none}
.faq details[open] summary::after{content:"–"}
.faq .faq-a{padding:0 16px 14px;color:var(--muted)}

/* ---------- Basic / Scientific calculator ---------- */
.calc-widget{max-width:430px;margin:0 auto;background:var(--surface);border:1px solid var(--border);border-radius:18px;box-shadow:var(--shadow-lg);padding:18px}
.calc-display{background:var(--surface2);border:1px solid var(--border);border-radius:12px;padding:14px 16px;text-align:right;margin-bottom:14px;min-height:84px}
.calc-expr{font-size:1.05rem;color:var(--muted);word-break:break-all;min-height:1.4em;font-variant-numeric:tabular-nums}
.calc-result{font-size:2rem;font-weight:800;font-variant-numeric:tabular-nums;word-break:break-all}
.calc-pad{display:grid;grid-template-columns:repeat(4,1fr);gap:9px}
.calc-pad button{padding:15px 0;font-size:1.12rem;font-weight:700;border-radius:11px;border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer}
.calc-pad button:hover{background:var(--surface2)}
.calc-pad button:active{transform:scale(.96)}
.calc-pad .op{background:var(--primary-soft);color:var(--primary-dark)}
[data-theme="dark"] .calc-pad .op{color:var(--primary)}
.calc-pad .eq{background:var(--primary);color:#fff;grid-column:span 2}
.calc-pad .danger{color:var(--danger)}
.sci-pad{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin-top:10px}
.sci-pad button{padding:10px 0;font-size:.92rem;border-radius:9px;border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer}
.sci-pad button:hover{background:var(--surface2)}

/* ---------- Footer ---------- */
.site-footer{background:var(--surface);border-top:1px solid var(--border);margin-top:56px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:26px;padding:44px 20px 30px}
@media(max-width:860px){.footer-grid{grid-template-columns:1fr 1fr}}
@media(max-width:520px){.footer-grid{grid-template-columns:1fr}}
.site-footer h4{font-size:.85rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin:0 0 12px}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li{margin-bottom:8px}
.site-footer a{color:var(--text);font-size:.92rem}
.footer-bottom{border-top:1px solid var(--border);padding:16px 20px;text-align:center;font-size:.83rem;color:var(--muted)}

/* ---------- Misc pages ---------- */
.legal-page{max-width:760px}
.legal-page h2{margin-top:1.6em}
.contact-form{max-width:560px}
.cta-band{background:linear-gradient(135deg,var(--primary),#6c3df4);border-radius:18px;color:#fff;text-align:center;padding:44px 24px}
.cta-band h2{color:#fff;margin-top:0}
.cta-band p{opacity:.9;max-width:560px;margin:0 auto 22px}
.cta-band .btn{background:#fff;color:var(--primary)}
.pop-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
@media(max-width:980px){.pop-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:520px){.pop-grid{grid-template-columns:1fr}}
.calc-tile{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:16px;color:var(--text);display:block}
.calc-tile:hover{text-decoration:none;border-color:var(--primary);box-shadow:var(--shadow)}
.calc-tile b{display:block;margin-bottom:4px}
.calc-tile span{font-size:.82rem;color:var(--muted)}
.error-page{text-align:center;padding:80px 20px}
.no-scroll-x{overflow-x:hidden}

/* ---------- Audit fixes: responsive overflow hardening (additive — no rules removed) ----------
   Root cause of the mobile horizontal overflow: at <=480px the sticky header tried to fit the
   logo + fixed-width search input + two 38px icon buttons in one row, exceeding 320px viewports.
   The search field now flexes and shrinks; results tables scroll internally; ad/dropdown widths
   are capped to the viewport. .no-scroll-x above remains only as a final safety net. */
@media(max-width:480px){
  .header-inner{gap:10px}
  .logo{font-size:1.15rem}
  .search-wrap{flex:1 1 auto;min-width:0}
  .search-wrap input{width:100%;min-width:0}
}
.search-drop{max-width:calc(100vw - 24px)}
.results table{display:block;overflow-x:auto}
@media(max-width:600px){.results td.v{white-space:normal;overflow-wrap:anywhere}}
.ad-slot,.ad-box{max-width:100%}