/* DailiCalc — Precision Blue theme (shared stylesheet) */
:root{
  --blue-700:#1e40af;
  --blue-600:#1d4ed8;
  --blue-500:#2563eb;
  --blue-100:#dbeafe;
  --blue-50:#eff6ff;
  --ink:#0f172a;
  --muted:#64748b;
  --bg:#ffffff;
  --surface:#ffffff;
  --card:#f8fafc;
  --border:#e2e8f0;
  --text-soft:#334155;
  --link:#1d4ed8;
  --input-bg:#ffffff;
  --ad-bg:#eef1f4;
  --ad-border:#cbd5e1;
  --ad-text:#94a3b8;
  --danger-bg:#fee2e2;
  --danger-text:#b91c1c;
  --green-600:#15803d;
  --green-50:#f0fdf4;
  --radius:12px;
  --shadow:0 1px 3px rgba(15,23,42,.08),0 4px 12px rgba(15,23,42,.06);
  --font:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
}
/* Dark mode */
[data-theme="dark"]{
  --blue-700:#8ab4ff;
  --blue-600:#3b82f6;
  --blue-100:#1e3a5f;
  --blue-50:#101f38;
  --ink:#e8eefb;
  --muted:#93a1bd;
  --bg:#0a0f1e;
  --surface:#111a2e;
  --card:#111a2e;
  --border:#22304d;
  --text-soft:#c3cede;
  --link:#7fb0ff;
  --input-bg:#0d1526;
  --ad-bg:#111a2e;
  --ad-border:#22304d;
  --ad-text:#5b6b8c;
  --danger-bg:#2b1a1a;
  --danger-text:#f87171;
  --green-600:#4ade80;
  --green-50:#0f2a1a;
  --shadow:0 1px 3px rgba(0,0,0,.4),0 4px 12px rgba(0,0,0,.3);
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:var(--font);color:var(--ink);background:var(--bg);line-height:1.6;font-size:16px}
img{max-width:100%}
a{color:var(--link);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:1080px;margin:0 auto;padding:0 20px}

/* Header */
.site-header{position:sticky;top:0;z-index:50;background:var(--surface);border-bottom:1px solid var(--border);box-shadow:0 1px 4px rgba(15,23,42,.05)}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:12px 0;flex-wrap:wrap}
.brand{display:flex;flex-direction:column;line-height:1.2}
.brand-name{font-size:1.5rem;font-weight:800;color:var(--blue-600);letter-spacing:-.5px}
.brand-name:hover{text-decoration:none}
.brand-tag{font-size:.72rem;color:var(--muted)}
.main-nav{display:flex;gap:4px;flex-wrap:wrap}
.main-nav a{padding:8px 12px;border-radius:8px;color:var(--ink);font-weight:500;font-size:.92rem}
.main-nav a:hover{background:var(--blue-50);color:var(--blue-700);text-decoration:none}

.theme-toggle{border:1px solid var(--border);background:var(--surface);color:var(--ink);border-radius:999px;padding:8px 14px;font-size:.88rem;font-weight:600;cursor:pointer;font-family:var(--font);white-space:nowrap}
.theme-toggle:hover{border-color:var(--blue-500)}

/* Ad placeholders */
.ad-slot{background:var(--ad-bg);border:1px dashed var(--ad-border);border-radius:8px;display:flex;align-items:center;justify-content:center;margin:20px auto;max-width:1080px}
.ad-slot span{font-size:.72rem;letter-spacing:2px;text-transform:uppercase;color:var(--ad-text)}
.ad-leaderboard{min-height:90px}
.ad-box{min-height:250px}
.ad-incontent{min-height:120px}

/* Breadcrumb */
.breadcrumb{font-size:.85rem;color:var(--muted);margin:18px 0 6px}
.breadcrumb a{color:var(--muted)}

/* Hero */
.hero{background:linear-gradient(180deg,var(--blue-50),var(--bg));padding:56px 0 40px;text-align:center;border-bottom:1px solid var(--border)}
.hero h1{font-size:2.4rem;letter-spacing:-1px;margin-bottom:10px;color:var(--ink)}
.hero p.lede{font-size:1.12rem;color:var(--muted);max-width:640px;margin:0 auto}

/* Category sections */
.cat-section{padding:36px 0 8px}
.cat-head{display:flex;align-items:baseline;justify-content:space-between;margin-bottom:16px}
.cat-head h2{font-size:1.45rem;letter-spacing:-.3px}
.cat-head p{color:var(--muted);font-size:.92rem}
.cards-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:16px}
.tool-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;display:block;color:var(--ink)}
.tool-card:hover{transform:translateY(-3px);box-shadow:0 6px 20px rgba(29,78,216,.12);text-decoration:none;border-color:var(--blue-100)}
.tool-card h3{font-size:1.02rem;margin-bottom:6px;color:var(--blue-700)}
.tool-card p{font-size:.88rem;color:var(--muted)}
.tool-card .go{font-size:.85rem;font-weight:600;color:var(--link);margin-top:10px;display:inline-block}

/* Tool page */
.tool-hero{padding:26px 0 6px}
.tool-hero h1{font-size:2rem;letter-spacing:-.6px;margin-bottom:8px}
p.lede{font-size:1.06rem;color:var(--muted);max-width:720px}

/* Calculator card */
.calc-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:26px;margin:22px 0}
.calc-card h2{font-size:1.2rem;margin-bottom:14px}
.mode-toggle{display:inline-flex;background:var(--card);border:1px solid var(--border);border-radius:999px;padding:4px;margin-bottom:18px}
.mode-toggle button{border:0;background:transparent;padding:8px 18px;border-radius:999px;font-size:.9rem;font-weight:600;color:var(--muted);cursor:pointer;font-family:var(--font)}
.mode-toggle button.active{background:var(--blue-600);color:#fff}
.field{margin-bottom:14px}
.field label{display:block;font-weight:600;font-size:.9rem;margin-bottom:6px}
.field .hint{font-weight:400;font-size:.8rem;color:var(--muted)}
.field input[type=number],.field input[type=text],.field select{width:100%;padding:11px 12px;border:1px solid var(--border);border-radius:8px;font-size:1rem;font-family:var(--font);background:var(--input-bg);color:var(--ink)}
.field input:focus,.field select:focus{outline:2px solid var(--blue-100);border-color:var(--blue-500)}
.field-row{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.btn{display:inline-block;background:var(--blue-600);color:#fff;border:0;border-radius:8px;padding:12px 26px;font-size:1rem;font-weight:700;cursor:pointer;font-family:var(--font)}
.btn:hover{background:var(--blue-700)}
.btn-secondary{background:var(--surface);color:var(--link);border:1px solid var(--border)}
.btn-secondary:hover{background:var(--blue-50)}
.result{display:none;background:var(--blue-50);border:1px solid var(--blue-100);border-radius:var(--radius);padding:20px;margin-top:18px}
.result.show{display:block}
.result .big{font-size:2rem;font-weight:800;color:var(--blue-700);letter-spacing:-.5px}
.result table{width:100%;border-collapse:collapse;margin-top:12px;font-size:.94rem}
.result table td{padding:8px 4px;border-top:1px solid var(--blue-100)}
.result table td:last-child{text-align:right;font-weight:600}
.result .note{font-size:.82rem;color:var(--muted);margin-top:10px}
.error{color:var(--danger-text);font-size:.85rem;margin-top:6px;display:none}

/* Steps */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:26px 0}
.step{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:18px}
.step .n{display:inline-flex;align-items:center;justify-content:center;width:30px;height:30px;border-radius:50%;background:var(--blue-600);color:#fff;font-weight:700;margin-bottom:10px}
.step h3{font-size:1rem;margin-bottom:6px}
.step p{font-size:.9rem;color:var(--muted)}

/* SEO text */
.seo-text{max-width:760px;margin:30px 0}
.seo-text h2{font-size:1.35rem;margin:26px 0 10px;letter-spacing:-.3px}
.seo-text h3{font-size:1.08rem;margin:18px 0 8px}
.seo-text p,.seo-text li{color:var(--text-soft);margin-bottom:10px}
.seo-text ul{padding-left:20px}

/* FAQ */
.faq{max-width:760px;margin:26px 0}
.faq h2{font-size:1.35rem;margin-bottom:12px}
.faq details{background:var(--surface);border:1px solid var(--border);border-radius:10px;margin-bottom:10px;overflow:hidden}
.faq summary{padding:14px 16px;font-weight:600;cursor:pointer;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(--blue-600);font-weight:700;flex-shrink:0}
.faq details[open] summary::after{content:"–"}
.faq details .a{padding:0 16px 16px;color:var(--text-soft);font-size:.95rem}

/* Related */
.related{margin:30px 0 10px}
.related h2{font-size:1.35rem;margin-bottom:14px}

/* Intro */
.intro{max-width:760px;margin:34px auto;color:var(--text-soft)}
.intro h2{font-size:1.4rem;margin-bottom:10px}

/* Footer */
.site-footer{background:#0b2a5b;color:#dbeafe;margin-top:48px;padding:44px 0 26px}
.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:24px;margin-bottom:26px}
.site-footer h4{color:#fff;font-size:.95rem;margin-bottom:10px}
.site-footer a{color:#bfdbfe;font-size:.88rem;display:block;margin-bottom:7px}
.site-footer a:hover{color:#fff}
.footer-bottom{border-top:1px solid rgba(255,255,255,.15);padding-top:18px;font-size:.84rem;color:#93c5fd;display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px}

/* QR */
.qr-output{display:none;text-align:center;margin-top:18px}
.qr-output.show{display:block}
.qr-output img{background:#fff;padding:12px;border:1px solid var(--border);border-radius:8px}

/* Dynamic rows (GPA) */
.course-row{display:grid;grid-template-columns:2fr 1fr 1fr auto;gap:8px;margin-bottom:8px;align-items:center}
.course-row input,.course-row select{padding:10px;border:1px solid var(--border);border-radius:8px;font-size:.95rem;font-family:var(--font);width:100%;background:var(--input-bg);color:var(--ink)}
.row-del{background:var(--danger-bg);border:0;color:var(--danger-text);border-radius:8px;padding:10px 12px;cursor:pointer;font-weight:700}

@media(max-width:640px){
  .hero h1{font-size:1.8rem}
  .tool-hero h1{font-size:1.55rem}
  /* Mobile header: centered brand + nav, icon-only theme toggle top-right */
  .header-inner{flex-direction:column;align-items:center;text-align:center;position:relative;padding:14px 0 12px}
  .brand{align-items:center}
  .main-nav{justify-content:center;width:100%;gap:8px}
  .main-nav a{background:var(--card);border:1px solid var(--border);border-radius:999px;padding:8px 15px;font-size:.88rem;font-weight:600;color:var(--ink)}
  .main-nav a:hover{background:var(--blue-50);border-color:var(--blue-100);color:var(--blue-700);text-decoration:none}
  .theme-toggle{position:absolute;top:14px;right:0;padding:8px 11px}
  .theme-toggle .tt-tx{display:none}
  .theme-toggle .tt-ic{font-size:1.05rem}
  .steps{grid-template-columns:1fr}
  .field-row{grid-template-columns:1fr}
  .course-row{grid-template-columns:1fr 1fr}
  .result .big{font-size:1.6rem}
  .main-nav a{padding:7px 9px;font-size:.85rem}
  /* Mobile hardening: no horizontal overflow, graceful stacking */
  .cat-head{flex-wrap:wrap;gap:4px}
  .mode-toggle{display:flex;flex-wrap:wrap}
  .mode-toggle button{flex:1 1 auto}
  .breadcrumb{overflow-wrap:anywhere}
  .result table{font-size:.86rem}
  .result table td{padding:7px 3px}
  .calc-card{padding:20px 16px}
  .tool-card{padding:18px}
  .ad-slot{margin-left:16px;margin-right:16px}
  .footer-grid{grid-template-columns:1fr 1fr}
}