/* ==========================================================================
   BD-Calculator — Shared Design System
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+Bengali:wght@500;600;700&family=Hind+Siliguri:wght@400;500;600;700&family=Tiro+Bangla&display=swap');

:root{
  --color-bg: #F7F5F0;
  --color-bg-soft: #F1EDE3;
  --color-card: #FFFFFF;
  --color-ink: #1A1A1A;
  --color-ink-soft: #4A4A45;
  --color-primary: #0B6E4F;
  --color-primary-dark: #084F39;
  --color-primary-soft: #E4F1EC;
  --color-gold: #C9A227;
  --color-gold-soft: #FBF3DC;
  --color-border: #DDD7C7;
  --color-danger: #B3422E;

  --font-display: 'Noto Serif Bengali', serif;
  --font-body: 'Hind Siliguri', sans-serif;
  --font-num: 'Tiro Bangla', serif;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-card: 0 2px 10px rgba(26,26,26,0.06), 0 1px 2px rgba(26,26,26,0.04);
  --shadow-raised: 0 8px 28px rgba(11,110,79,0.14);
  --max-width: 1080px;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  background:var(--color-bg);
  color:var(--color-ink);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block;}
a{color:inherit;text-decoration:none;}
ul{list-style:none;margin:0;padding:0;}
h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:700;
  line-height:1.35;
  margin:0 0 .6em;
  color:var(--color-primary-dark);
}
p{margin:0 0 1.1em;}
.container{max-width:var(--max-width);margin:0 auto;padding:0 20px;}

/* Skip link */
.skip-link{
  position:absolute;left:-999px;top:0;background:var(--color-primary);color:#fff;
  padding:10px 16px;border-radius:0 0 8px 0;z-index:200;
}
.skip-link:focus{left:0;}

/* ---------------- Header ---------------- */
.site-header{
  background:var(--color-card);
  border-bottom:1px solid var(--color-border);
  position:sticky;top:0;z-index:100;
}
.header-inner{
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 20px;max-width:var(--max-width);margin:0 auto;gap:16px;
}
.logo{
  display:flex;align-items:center;gap:10px;font-family:var(--font-display);
  font-weight:700;font-size:1.4rem;color:var(--color-primary-dark);flex-shrink:0;
}
.logo .logo-mark{
  width:38px;height:38px;border-radius:9px;
  background:linear-gradient(155deg,var(--color-primary) 0%,var(--color-primary-dark) 100%);
  display:flex;align-items:center;justify-content:center;flex-shrink:0;
  box-shadow:0 3px 8px rgba(11,110,79,.3);
}
.logo .logo-mark svg{width:21px;height:21px;}
.logo .logo-text-bn{font-size:.62rem;font-weight:500;color:var(--color-ink-soft);display:block;font-family:var(--font-body);letter-spacing:.02em;}

.main-nav{display:flex;align-items:center;gap:26px;}
.main-nav a{
  font-size:.97rem;font-weight:600;color:var(--color-ink-soft);
  position:relative;padding:6px 0;white-space:nowrap;
}
.main-nav a:hover, .main-nav a.active{color:var(--color-primary-dark);}
.main-nav a.active::after{
  content:"";position:absolute;left:0;right:0;bottom:-2px;height:2px;background:var(--color-gold);
}
.nav-toggle{
  display:none;background:none;border:2px solid var(--color-border);border-radius:8px;
  width:42px;height:42px;cursor:pointer;flex-shrink:0;
}
.nav-toggle span{display:block;width:20px;height:2px;background:var(--color-ink);margin:4px auto;border-radius:2px;}

/* ---------------- Buttons ---------------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:13px 26px;border-radius:999px;font-weight:700;font-size:.97rem;
  cursor:pointer;border:none;transition:transform .15s ease, box-shadow .15s ease;
}
.btn-primary{background:var(--color-primary);color:#fff;box-shadow:var(--shadow-raised);}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 12px 30px rgba(11,110,79,.22);}
.btn-ghost{background:transparent;color:var(--color-primary-dark);border:1.5px solid var(--color-border);}
.btn-ghost:hover{border-color:var(--color-primary);}

/* ---------------- Hero ---------------- */
.hero{
  padding:64px 20px 48px;background:
    radial-gradient(circle at 85% -10%, rgba(201,162,39,0.14), transparent 55%),
    radial-gradient(circle at 0% 110%, rgba(11,110,79,0.10), transparent 50%);
}
.hero-inner{max-width:var(--max-width);margin:0 auto;text-align:center;}
.eyebrow{
  display:inline-flex;align-items:center;gap:8px;
  background:var(--color-gold-soft);color:#8a6c10;border:1px solid #ecd9a0;
  font-size:.83rem;font-weight:700;padding:6px 16px;border-radius:999px;margin-bottom:22px;
}
.hero h1{font-size:clamp(1.9rem,4.2vw,2.9rem);max-width:780px;margin:0 auto .5em;}
.hero .lede{
  max-width:620px;margin:0 auto 30px;color:var(--color-ink-soft);font-size:1.08rem;
}
.hero-stats{display:flex;gap:34px;justify-content:center;flex-wrap:wrap;margin-top:36px;}
.hero-stat strong{display:block;font-family:var(--font-display);font-size:1.6rem;color:var(--color-primary-dark);}
.hero-stat span{font-size:.86rem;color:var(--color-ink-soft);}

/* ---------------- Calculator Grid ---------------- */
.section{padding:54px 0;}
.section-head{text-align:center;max-width:640px;margin:0 auto 38px;}
.section-head h2{font-size:clamp(1.5rem,3vw,2rem);}
.section-head p{color:var(--color-ink-soft);}

.calc-grid{
  display:grid;grid-template-columns:repeat(auto-fill,minmax(252px,1fr));gap:18px;
}
.calc-card{
  background:var(--color-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);
  padding:24px 22px;box-shadow:var(--shadow-card);transition:transform .18s ease, box-shadow .18s ease, border-color .18s ease;
  display:flex;flex-direction:column;gap:14px;position:relative;overflow:hidden;
}
.calc-card::before{
  content:"";position:absolute;top:0;left:0;width:5px;height:0;background:var(--color-gold);
  transition:height .25s ease;
}
.calc-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-raised);border-color:var(--color-primary);}
.calc-card:hover::before{height:100%;}
.calc-icon{
  width:50px;height:50px;border-radius:12px;background:var(--color-primary-soft);
  display:flex;align-items:center;justify-content:center;flex-shrink:0;
}
.calc-icon svg{width:26px;height:26px;stroke:var(--color-primary-dark);}
.calc-card h3{font-size:1.08rem;margin-bottom:.25em;}
.calc-card p{font-size:.89rem;color:var(--color-ink-soft);margin-bottom:0;flex-grow:1;}
.calc-card .calc-go{
  font-size:.85rem;font-weight:700;color:var(--color-primary-dark);
  display:inline-flex;align-items:center;gap:5px;
}
.calc-card .calc-go svg{width:14px;height:14px;transition:transform .18s ease;}
.calc-card:hover .calc-go svg{transform:translateX(4px);}
.calc-card .calc-tag{
  position:absolute;top:14px;right:14px;font-size:.68rem;font-weight:700;
  background:var(--color-gold-soft);color:#8a6c10;padding:3px 9px;border-radius:999px;
}

.category-label{
  font-size:.8rem;font-weight:700;color:var(--color-primary-dark);text-transform:uppercase;
  letter-spacing:.06em;margin:34px 0 16px;display:flex;align-items:center;gap:10px;
}
.category-label::after{content:"";flex-grow:1;height:1px;background:var(--color-border);}
.category-label:first-child{margin-top:0;}

/* ---------------- Trust strip ---------------- */
.trust-strip{
  background:var(--color-primary-dark);color:#fff;padding:30px 20px;
}
.trust-inner{
  max-width:var(--max-width);margin:0 auto;display:flex;flex-wrap:wrap;gap:24px;
  justify-content:space-between;align-items:center;
}
.trust-item{display:flex;align-items:center;gap:10px;font-size:.92rem;font-weight:600;color:#EAF4EF;}
.trust-item svg{width:20px;height:20px;flex-shrink:0;stroke:var(--color-gold);}

/* ---------------- Calculator page layout ---------------- */
.breadcrumb{
  font-size:.84rem;color:var(--color-ink-soft);padding:16px 0;
}
.breadcrumb a{color:var(--color-primary-dark);font-weight:600;}
.breadcrumb span{margin:0 6px;color:#bbb;}

.article-head{padding:8px 0 18px;}
.article-head .eyebrow{margin-bottom:16px;}
.article-head h1{font-size:clamp(1.6rem,3.6vw,2.3rem);}
.article-meta{
  display:flex;align-items:center;gap:14px;margin-top:18px;flex-wrap:wrap;
  font-size:.86rem;color:var(--color-ink-soft);
}
.article-meta .author-chip{display:flex;align-items:center;gap:8px;}
.article-meta .author-chip img{width:30px;height:30px;border-radius:50%;object-fit:cover;}
.article-meta .author-chip strong{color:var(--color-ink);}

.article-body{
  font-size:1.04rem;color:#2b2b27;
}
.article-body h2{font-size:1.35rem;margin-top:1.4em;}
.article-body h3{font-size:1.12rem;margin-top:1.2em;}
.article-body ul, .article-body ol{margin:0 0 1.1em;padding-left:1.4em;}
.article-body li{margin-bottom:.4em;}
.article-body{padding:18px 0;}

/* document-style calculator frame */
.calc-frame{
  background:var(--color-card);
  border:1px solid var(--color-border);
  border-radius:var(--radius-lg);
  box-shadow:var(--shadow-card);
  margin:30px 0 38px;
  position:relative;
  overflow:hidden;
}
.calc-frame::before{
  content:"";position:absolute;inset:0;border-radius:var(--radius-lg);
  background-image:
    linear-gradient(var(--color-border) 1px, transparent 1px);
  background-size:100% 100%;
  opacity:0;
  pointer-events:none;
}
.calc-frame-tag{
  position:absolute;top:0;right:24px;background:var(--color-gold);color:#3a2e08;
  font-size:.74rem;font-weight:700;padding:5px 14px;border-radius:0 0 8px 8px;
  letter-spacing:.03em;
}
.calc-frame-corner{
  position:absolute;top:14px;left:14px;width:22px;height:22px;
  border-top:2px solid var(--color-gold);border-left:2px solid var(--color-gold);
  border-radius:4px 0 0 0;opacity:.7;
}
.calc-frame-corner.br{
  top:auto;left:auto;bottom:14px;right:14px;
  border-top:none;border-left:none;
  border-bottom:2px solid var(--color-gold);border-right:2px solid var(--color-gold);
  border-radius:0 0 4px 0;
}
.calc-frame-inner{padding:38px 28px 30px;}
.calc-frame-head{text-align:center;margin-bottom:26px;}
.calc-frame-head h2{font-size:1.35rem;margin-bottom:.2em;}
.calc-frame-head p{color:var(--color-ink-soft);font-size:.92rem;margin:0;}

.calc-form{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:18px;
}
.field{display:flex;flex-direction:column;gap:7px;}
.field label{font-size:.88rem;font-weight:700;color:var(--color-ink);}
.field .hint{font-size:.78rem;color:var(--color-ink-soft);font-weight:400;}
.field input, .field select{
  border:1.5px solid var(--color-border);border-radius:var(--radius-sm);
  padding:12px 14px;font-size:1rem;font-family:var(--font-body);background:#FCFBF8;
  color:var(--color-ink);width:100%;transition:border-color .15s ease, box-shadow .15s ease;
}
.field input:focus, .field select:focus{
  outline:none;border-color:var(--color-primary);box-shadow:0 0 0 3px rgba(11,110,79,.13);
}
.field-actions{grid-column:1/-1;display:flex;gap:12px;margin-top:6px;flex-wrap:wrap;}

.calc-result{
  margin-top:28px;padding:24px 22px;border-radius:var(--radius-md);
  background:var(--color-primary-soft);border:1.5px dashed var(--color-primary);
  display:none;
}
.calc-result.show{display:block;animation:fadeUp .35s ease;}
@keyframes fadeUp{from{opacity:0;transform:translateY(8px);}to{opacity:1;transform:translateY(0);}}
.calc-result-title{
  font-size:.85rem;font-weight:700;color:var(--color-primary-dark);text-transform:uppercase;
  letter-spacing:.04em;margin-bottom:14px;display:flex;align-items:center;gap:8px;
}
.calc-result-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:16px;}
.result-box{background:#fff;border-radius:var(--radius-sm);padding:14px 16px;border:1px solid var(--color-border);}
.result-box .label{font-size:.8rem;color:var(--color-ink-soft);margin-bottom:4px;}
.result-box .value{font-family:var(--font-num);font-size:1.32rem;font-weight:700;color:var(--color-primary-dark);}
.result-box.highlight{background:var(--color-gold-soft);border-color:#e8d28f;}
.result-box.highlight .value{color:#8a6c10;}
.result-note{font-size:.84rem;color:var(--color-ink-soft);margin-top:14px;margin-bottom:0;}

.calc-table-wrap{margin-top:20px;overflow-x:auto;max-height:360px;overflow-y:auto;border-radius:var(--radius-sm);border:1px solid var(--color-border);}
table.calc-table{width:100%;border-collapse:collapse;font-size:.9rem;background:#fff;}
table.calc-table th{
  position:sticky;top:0;background:var(--color-primary-dark);color:#fff;
  padding:10px 12px;text-align:right;font-weight:600;
}
table.calc-table th:first-child, table.calc-table td:first-child{text-align:right;}
table.calc-table td{padding:9px 12px;text-align:right;border-bottom:1px solid var(--color-border);font-family:var(--font-num);white-space:nowrap;}
table.calc-table tr:nth-child(even){background:#FAF8F2;}

.error-text{color:var(--color-danger);font-size:.86rem;margin-top:10px;display:none;font-weight:600;}
.error-text.show{display:block;}

/* ---------------- Author block ---------------- */
.author-block{
  display:flex;gap:18px;background:var(--color-card);border:1px solid var(--color-border);
  border-radius:var(--radius-lg);padding:24px;margin:40px 0;box-shadow:var(--shadow-card);
  align-items:flex-start;
}
.author-block img{
  width:74px;height:74px;border-radius:50%;object-fit:cover;flex-shrink:0;
  border:3px solid var(--color-primary-soft);
}
.author-block .author-name-row{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:4px;}
.author-block h4{margin:0;font-size:1.05rem;}
.author-block .verified{
  font-size:.68rem;font-weight:700;background:var(--color-primary-soft);color:var(--color-primary-dark);
  padding:2px 9px;border-radius:999px;display:inline-flex;align-items:center;gap:4px;
}
.author-block p{font-size:.92rem;color:var(--color-ink-soft);margin:0;}

/* ---------------- Related posts ---------------- */
.related-posts{margin:40px 0;}
.related-posts h3{font-size:1.15rem;margin-bottom:16px;}
.related-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:18px;}
.related-card{
  display:flex;gap:14px;background:var(--color-card);border:1px solid var(--color-border);
  border-radius:var(--radius-md);padding:14px;align-items:center;transition:border-color .15s ease, transform .15s ease;
}
.related-card:hover{border-color:var(--color-primary);transform:translateY(-2px);}
.related-card img{width:64px;height:64px;border-radius:10px;object-fit:cover;flex-shrink:0;}
.related-card h4{font-size:.95rem;margin:0 0 4px;color:var(--color-ink);}
.related-card span{font-size:.8rem;color:var(--color-primary-dark);font-weight:600;}

/* ---------------- Comments ---------------- */
.comments-block{
  margin:40px 0;background:var(--color-card);border:1px solid var(--color-border);
  border-radius:var(--radius-lg);padding:28px 24px;box-shadow:var(--shadow-card);
}
.comments-block h3{font-size:1.15rem;margin-bottom:4px;}
.comments-block .comment-sub{font-size:.88rem;color:var(--color-ink-soft);margin-bottom:20px;}
.comment-form{display:flex;flex-direction:column;gap:12px;margin-bottom:26px;}
.comment-form .row2{display:grid;grid-template-columns:1fr 1fr;gap:12px;}
.comment-form input, .comment-form textarea{
  border:1.5px solid var(--color-border);border-radius:var(--radius-sm);
  padding:11px 14px;font-family:var(--font-body);font-size:.96rem;background:#FCFBF8;width:100%;
}
.comment-form textarea{resize:vertical;min-height:90px;}
.comment-form input:focus, .comment-form textarea:focus{outline:none;border-color:var(--color-primary);box-shadow:0 0 0 3px rgba(11,110,79,.13);}
.comment-list{display:flex;flex-direction:column;gap:16px;}
.comment-item{display:flex;gap:12px;padding-top:16px;border-top:1px solid var(--color-border);}
.comment-item:first-child{border-top:none;padding-top:0;}
.comment-avatar{
  width:40px;height:40px;border-radius:50%;background:var(--color-primary);color:#fff;
  display:flex;align-items:center;justify-content:center;font-weight:700;flex-shrink:0;font-family:var(--font-display);
}
.comment-body strong{font-size:.92rem;}
.comment-body .comment-date{font-size:.76rem;color:var(--color-ink-soft);margin-left:8px;}
.comment-body p{margin:4px 0 0;font-size:.92rem;color:#3a3a35;}
.comment-empty{font-size:.9rem;color:var(--color-ink-soft);font-style:italic;}

/* ---------------- Footer ---------------- */
.site-footer{background:var(--color-primary-dark);color:#D9E9E0;margin-top:60px;}
.footer-top{padding:52px 20px 36px;max-width:640px;margin:0 auto;
  display:flex;flex-direction:column;align-items:center;text-align:center;}
.footer-col h5{color:#fff;font-family:var(--font-display);font-size:1rem;margin-bottom:14px;}
.footer-col p{font-size:.96rem;line-height:1.8;color:#C7DED2;margin-bottom:0;max-width:560px;}
.footer-col ul{display:flex;flex-direction:column;gap:9px;}
.footer-col a{font-size:.88rem;color:#CFE3D8;}
.footer-col a:hover{color:#fff;}
.footer-logo{display:flex;align-items:center;gap:10px;margin-bottom:18px;justify-content:center;}
.footer-logo .logo-mark{
  width:38px;height:38px;border-radius:9px;background:rgba(255,255,255,.12);
  display:flex;align-items:center;justify-content:center;
}
.footer-logo .logo-mark svg{width:20px;height:20px;stroke:var(--color-gold);}
.footer-logo strong{font-family:var(--font-display);color:#fff;font-size:1.3rem;}
.footer-bottom{
  border-top:1px solid rgba(255,255,255,.12);padding:18px 20px;text-align:center;
  font-size:.83rem;color:#A9C5B7;
}
.footer-bottom a{color:#CFE3D8;font-weight:600;}

/* ---------------- Static page ---------------- */
.static-page{padding:40px 0 70px;}
.static-page h1{font-size:clamp(1.7rem,3.6vw,2.3rem);}
.static-page .updated{font-size:.85rem;color:var(--color-ink-soft);margin-bottom:30px;}
.static-page h2{font-size:1.25rem;margin-top:1.6em;}
.static-page ul{padding-left:1.4em;list-style:disc;margin-bottom:1.1em;}
.static-page li{margin-bottom:.4em;}

.about-author-card{
  display:flex;gap:24px;background:var(--color-card);border:1px solid var(--color-border);
  border-radius:var(--radius-lg);padding:28px;margin:28px 0;box-shadow:var(--shadow-card);
  align-items:flex-start;flex-wrap:wrap;
}
.about-author-card img{width:120px;height:120px;border-radius:50%;object-fit:cover;border:4px solid var(--color-primary-soft);}
.about-author-card .info{flex:1;min-width:220px;}

/* ---------------- Responsive ---------------- */
@media (max-width:760px){
  .nav-toggle{display:block;}
  .main-nav{
    position:fixed;top:68px;left:0;right:0;bottom:0;background:var(--color-card);
    flex-direction:column;align-items:flex-start;padding:24px;gap:4px;
    transform:translateX(100%);transition:transform .25s ease;overflow-y:auto;z-index:99;
  }
  .main-nav.open{transform:translateX(0);}
  .main-nav a{width:100%;padding:13px 4px;border-bottom:1px solid var(--color-border);font-size:1.05rem;}
  .hero{padding:42px 16px 34px;}
  .hero-stats{gap:22px;}
  .calc-form{grid-template-columns:1fr;}
  .comment-form .row2{grid-template-columns:1fr;}
  .about-author-card{flex-direction:column;align-items:center;text-align:center;}
  .author-block{flex-direction:column;text-align:center;align-items:center;}
  .calc-frame-inner{padding:28px 18px 24px;}
}
@media (max-width:480px){
  .calc-result-grid{grid-template-columns:1fr 1fr;}
}

@media (prefers-reduced-motion: reduce){
  *{animation-duration:0.01ms !important;transition-duration:0.01ms !important;}
}