/* ===== CalcHub styles — responsive, RTL-aware ===== */
:root{
  --bg:#f5f7fb; --surface:#ffffff; --text:#1b2431; --muted:#5b6b7f;
  --primary:#2563eb; --primary-dark:#1d4ed8; --border:#e3e8ef;
  --accent:#0ea5e9; --ok:#16a34a; --shadow:0 1px 3px rgba(16,24,40,.06),0 1px 2px rgba(16,24,40,.04);
  --radius:12px; --maxw:1120px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{overflow-x:clip;max-width:100%}
body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",Tahoma,"Noto Sans Arabic",Arial,sans-serif;
  background:var(--bg);color:var(--text);line-height:1.6;font-size:16px}
[dir=rtl] body{font-family:"Segoe UI","Noto Sans Arabic",Tahoma,system-ui,sans-serif}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%}
.container{max-width:var(--maxw);margin:0 auto;padding:0 16px}
/* Accessible skip link — hidden without causing horizontal overflow (RTL-safe) */
.skip-link{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;
  clip:rect(0 0 0 0);white-space:nowrap;border:0}
.skip-link:focus{position:fixed;width:auto;height:auto;margin:0;clip:auto;overflow:visible;
  inset-inline-start:8px;top:8px;background:#fff;padding:8px 14px;z-index:100;border:1px solid var(--border);border-radius:8px}

/* Header */
.site-header{background:var(--surface);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:50}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:62px;gap:16px}
.brand{display:inline-flex;align-items:center;gap:8px;font-weight:800;font-size:1.25rem;color:var(--text)}
.brand:hover{text-decoration:none}
.brand-icon{font-size:1.4rem}
.brand-logo{height:34px;width:auto;display:block}
.footer-logo{height:38px;width:auto;display:block;margin-bottom:10px}
@media(max-width:640px){.brand-logo{height:30px}}
.site-nav{display:flex;align-items:center;gap:6px}
.site-nav a{padding:8px 12px;border-radius:8px;color:var(--muted);font-weight:600;font-size:.95rem}
.site-nav a:hover{background:var(--bg);color:var(--text);text-decoration:none}
.lang-btn{border:1px solid var(--border);color:var(--primary);background:var(--surface);padding:8px 12px;
  border-radius:8px;font-weight:600;font-size:.95rem;cursor:pointer;font-family:inherit}
.lang-switch{position:relative;display:inline-block}
.lang-menu{position:absolute;inset-inline-end:0;top:calc(100% + 6px);background:var(--surface);border:1px solid var(--border);
  border-radius:10px;box-shadow:0 8px 24px rgba(16,24,40,.12);padding:6px;min-width:150px;z-index:60;
  display:none;flex-direction:column;max-height:60vh;overflow:auto}
.lang-switch:hover .lang-menu,.lang-switch:focus-within .lang-menu{display:flex}
.lang-menu a{padding:8px 12px;border-radius:7px;color:var(--text);font-size:.92rem}
.lang-menu a:hover{background:var(--bg);text-decoration:none}
.lang-menu a.active{background:#eef4ff;color:var(--primary-dark);font-weight:700}
.nav-toggle{display:none;background:none;border:1px solid var(--border);border-radius:8px;font-size:1.3rem;
  width:42px;height:42px;cursor:pointer}

/* Hero */
.hero{text-align:center;padding:48px 0 24px}
.hero h1{font-size:2.2rem;margin:0 0 12px}
.hero-sub{color:var(--muted);max-width:640px;margin:0 auto 22px;font-size:1.08rem}
.search-wrap{max-width:520px;margin:0 auto 8px}
#calc-search{width:100%;padding:14px 18px;border:1px solid var(--border);border-radius:999px;font-size:1rem;
  background:var(--surface);box-shadow:var(--shadow)}
#calc-search:focus{outline:2px solid var(--primary);border-color:transparent}

/* Sections & grids */
.section{margin:34px 0}
.section-title{font-size:1.35rem;margin:0 0 16px;display:flex;align-items:center;gap:8px}
.calc-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px}
.calc-card{display:flex;gap:12px;align-items:flex-start;background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius);padding:16px;box-shadow:var(--shadow);transition:transform .12s,box-shadow .12s}
.calc-card:hover{transform:translateY(-2px);box-shadow:0 6px 18px rgba(16,24,40,.10);text-decoration:none}
.calc-card-icon{font-size:1.7rem;line-height:1}
.calc-card-body{display:flex;flex-direction:column;gap:3px}
.calc-card-title{font-weight:700;color:var(--text)}
.calc-card-desc{font-size:.86rem;color:var(--muted)}

.cat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:14px}
.cat-card{display:flex;flex-direction:column;align-items:center;gap:6px;background:var(--surface);
  border:1px solid var(--border);border-radius:var(--radius);padding:22px 14px;box-shadow:var(--shadow);color:var(--text)}
.cat-card:hover{text-decoration:none;border-color:var(--primary)}
.cat-icon{font-size:2rem}
.cat-name{font-weight:700}
.cat-count{font-size:.8rem;color:var(--muted);background:var(--bg);padding:1px 10px;border-radius:999px}
.cat-icon-sm{font-size:1.2rem}

/* Breadcrumb / titles */
.breadcrumb{font-size:.88rem;color:var(--muted);margin:18px 0 6px}
.breadcrumb a{color:var(--muted)}
.page-title{font-size:1.8rem;margin:6px 0 18px}

/* Calculator page */
.calc-page{margin:10px 0 20px}
.calc-head{display:flex;gap:14px;align-items:center;margin:6px 0 20px}
.calc-head-icon{font-size:2.6rem}
.calc-head h1{margin:0;font-size:1.7rem}
.calc-lead{margin:4px 0 0;color:var(--muted)}
.calc-layout{display:grid;grid-template-columns:1fr 300px;gap:24px;align-items:start}
.calc-main{min-width:0}
.calc-form{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:20px;box-shadow:var(--shadow)}
.field{margin-bottom:14px}
.field label{display:block;font-weight:600;font-size:.92rem;margin-bottom:6px}
.field input,.field select{width:100%;padding:11px 12px;border:1px solid var(--border);border-radius:9px;
  font-size:1rem;background:#fff;color:var(--text)}
.field input:focus,.field select:focus{outline:2px solid var(--primary);border-color:transparent}
.calc-actions{display:flex;gap:10px;margin-top:6px}
.btn{padding:12px 22px;border-radius:9px;border:1px solid transparent;font-size:1rem;font-weight:700;
  cursor:pointer;font-family:inherit}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-dark)}
.btn-ghost{background:transparent;border-color:var(--border);color:var(--muted)}
.btn-ghost:hover{background:var(--bg)}

.calc-result{margin-top:20px;background:#eef4ff;border:1px solid #cfe0ff;border-radius:var(--radius);padding:20px}
.calc-result h2{margin:0 0 12px;font-size:1.2rem}
.result-primary{font-size:2rem;font-weight:800;color:var(--primary-dark);margin:0 0 10px}
.result-table{width:100%;border-collapse:collapse}
.result-table td{padding:8px 4px;border-bottom:1px solid #dbe6ff}
.result-table td:last-child{text-align:end;font-weight:700}
.result-badge{display:inline-block;padding:3px 12px;border-radius:999px;font-weight:700;font-size:.9rem;color:#fff}
.result-note{font-size:.8rem;color:var(--muted);margin:12px 0 0}

.calc-aside{display:flex;flex-direction:column;gap:16px}
.related-box{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:16px}
.related-box h2{font-size:1.05rem;margin:0 0 10px}
.related-box ul{list-style:none;margin:0;padding:0}
.related-box li{margin:4px 0}

.calc-article{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:22px;margin-top:24px}
.calc-article h2{font-size:1.25rem;margin-top:0}
.calc-article em{color:var(--primary-dark);font-style:normal;background:#eef4ff;padding:1px 6px;border-radius:5px}

/* FAQ */
.faq-section{margin-top:24px}
.faq-section h2{font-size:1.3rem;margin:0 0 12px}
.faq-item{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:14px 18px;margin-bottom:10px}
.faq-item summary{font-weight:700;cursor:pointer;list-style:none}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::before{content:"＋";color:var(--primary);font-weight:800;margin-inline-end:8px}
.faq-item[open] summary::before{content:"－"}
.faq-item p{margin:10px 0 0;color:var(--muted)}

/* Ads */
.ad-box{display:flex;align-items:center;justify-content:center;min-height:90px;background:repeating-linear-gradient(45deg,#f0f3f8,#f0f3f8 10px,#eef1f7 10px,#eef1f7 20px);
  border:1px dashed #cbd5e1;border-radius:10px;color:#94a3b8;font-size:.8rem;margin:20px 0}
.ad-side{min-height:250px}

/* Prose (static pages) */
.prose{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px;
  margin:12px 0 30px;max-width:820px}
.prose h1{margin-top:0}
.prose h2{font-size:1.2rem;margin-top:22px}
.prose a{color:var(--primary)}

/* Footer */
.site-footer{background:#0f1b2d;color:#c7d2e0;margin-top:40px;padding:36px 0 16px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:24px}
.footer-brand{color:#fff}
.footer-tag{color:#8ea2bd;font-size:.9rem}
.footer-col h3{font-size:1rem;color:#fff;margin:0 0 10px}
.footer-col ul{list-style:none;margin:0;padding:0}
.footer-col li{margin:6px 0}
.footer-col a{color:#c7d2e0;font-size:.92rem}
.footer-bottom{border-top:1px solid #22304a;margin-top:22px;padding-top:14px;display:flex;
  justify-content:space-between;gap:12px;flex-wrap:wrap;font-size:.82rem;color:#8ea2bd}
.footer-credit{width:100%;order:3;text-align:center;color:#8ea2bd}
.footer-credit a{color:var(--primary);font-weight:600;text-decoration:none}
.footer-credit a:hover{text-decoration:underline}

/* Scientific calculator */
.sci-calc{max-width:520px}
.sci-display{background:#0f1b2d;border:1px solid #22304a;border-radius:12px;padding:14px 16px;margin-bottom:12px;text-align:right;overflow:hidden}
.sci-expr{color:#8ea2bd;font-size:.9rem;min-height:1.1em;word-break:break-all}
.sci-out{color:#fff;font-size:2rem;font-weight:600;word-break:break-all;line-height:1.2}
.sci-modebar{display:flex;align-items:center;justify-content:space-between;margin-bottom:10px}
.sci-mode{background:var(--primary);color:#fff;border:0;border-radius:8px;padding:6px 14px;font-weight:700;cursor:pointer;letter-spacing:.5px}
.sci-mem{color:var(--primary);font-weight:700;min-width:1em}
.sci-keys{display:grid;grid-template-columns:repeat(6,1fr);gap:8px}
.sci-k{border:1px solid #22304a;background:#16233b;color:#e8eef7;border-radius:10px;padding:14px 0;font-size:1.05rem;cursor:pointer;transition:background .12s,transform .05s;-webkit-user-select:none;user-select:none}
.sci-k:hover{background:#1e3252}
.sci-k:active{transform:translateY(1px)}
.sci-k.num{background:#1b2a44}
.sci-k.op{background:#243a5e;font-weight:600}
.sci-k.fn{font-size:.92rem;color:#cfe0f5}
.sci-k.act{background:#3a2440;color:#ffd7e6}
.sci-k.eq{background:var(--primary);color:#fff;font-weight:700}
.sci-k.eq:hover{filter:brightness(1.1)}
@media(max-width:520px){.sci-k{padding:12px 0;font-size:.98rem}.sci-out{font-size:1.6rem}}

/* Text tools (Base64 / URL, encoders) */
.tool-io{max-width:640px}
.tool-row{display:flex;align-items:center;gap:10px;margin-bottom:12px;flex-wrap:wrap}
.tool-label{display:block;font-weight:600;color:var(--text);margin:10px 0 6px}
.tool-select{padding:9px 12px;border:1px solid var(--border);border-radius:8px;background:var(--surface);color:var(--text);font-size:1rem}
.tool-area{width:100%;padding:12px;border:1px solid var(--border);border-radius:10px;background:var(--surface);color:var(--text);font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.95rem;resize:vertical;box-sizing:border-box}
.tool-area[readonly]{background:var(--bg)}
.tool-actions{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0}
.sn-table{width:100%;border-collapse:collapse;margin-top:8px;max-width:640px}
.sn-table th,.sn-table td{text-align:start;padding:9px 12px;border-bottom:1px solid var(--border);font-size:.95rem}
.sn-table th{color:var(--muted);font-weight:600;width:45%}
.sn-table .mono{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
.sn-err{color:#b91c1c;font-weight:600;margin-top:10px}
/* Matrix calculator */
.mx-size{display:inline-flex;align-items:center;gap:6px;font-weight:600;color:var(--text)}
.mx-dim{padding:6px 8px}
.mx-panes{display:flex;gap:22px;flex-wrap:wrap;margin:14px 0}
.mx-cap{font-weight:700;color:var(--muted);margin-bottom:6px}
.mx-grid{display:grid;gap:6px}
.mx-cell{width:56px;padding:8px 4px;text-align:center;border:1px solid var(--border);border-radius:6px;background:var(--surface);color:var(--text);font-size:.95rem}
.mx-out{gap:0;border:2px solid var(--primary);border-radius:8px;overflow:hidden;display:inline-grid}
.mx-ocell{min-width:56px;padding:9px 12px;text-align:center;font-family:ui-monospace,Consolas,monospace;border-bottom:1px solid var(--border);border-inline-start:1px solid var(--border)}
.mx-scalar{font-size:1.3rem;font-weight:700;color:var(--primary)}
.mx-result{margin-top:14px}
/* Big number */
.big-digits{color:var(--muted);font-weight:400;font-size:.85rem}
/* Long division */
.ld-summary{margin-top:14px;padding:12px 14px;background:var(--bg);border:1px solid var(--border);border-radius:10px;font-size:1.05rem}
.ld-eq{margin-top:6px;font-family:ui-monospace,Consolas,monospace;color:var(--primary);font-weight:700}
.ld-steps{margin-top:14px;padding-inline-start:22px;max-width:640px}
.ld-steps li{padding:5px 0;border-bottom:1px dashed var(--border);font-family:ui-monospace,Consolas,monospace;font-size:.92rem}
/* Time zone */
.tz-out{margin-top:16px;padding:16px 18px;background:var(--bg);border:1px solid var(--border);border-radius:12px;max-width:640px}
.tz-big{font-size:1.25rem;font-weight:700;color:var(--text)}
.tz-sub{color:var(--muted);margin:4px 0 10px}
.tz-diff{border-top:1px solid var(--border);padding-top:10px}

/* 404 */
.notfound{text-align:center;padding:60px 0}
.notfound h1{font-size:5rem;margin:0;color:var(--primary)}

/* Responsive */
@media(max-width:860px){
  .calc-layout{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:640px){
  .nav-toggle{display:block}
  .site-nav{position:absolute;top:62px;inset-inline-start:0;inset-inline-end:0;background:var(--surface);
    flex-direction:column;align-items:stretch;padding:8px;border-bottom:1px solid var(--border);display:none}
  .site-nav.open{display:flex}
  .site-nav a{padding:12px}
  .hero h1{font-size:1.7rem}
  .footer-grid{grid-template-columns:1fr}
}