/* ══════════════════════════════════════════════════════════
   GSTBill.app — Shared Design System
   Navy + Emerald palette, DM Sans, mobile-first
   ══════════════════════════════════════════════════════════ */

/* ── RESET ── */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%;scroll-behavior:smooth;}
body{-webkit-tap-highlight-color:rgba(11,37,69,.12);overflow-x:hidden;}
img,svg,video{max-width:100%;height:auto;display:block;}
button,input,select,textarea{font:inherit;color:inherit;}

/* ── BRAND VARIABLES ── */
:root{
  /* Primary brand */
  --navy:#0B2545;
  --navy-deep:#081A31;
  --navy-tint:#13315C;
  /* Emerald accent (replaces WhatsApp green) */
  --green:#059669;
  --green-dark:#047857;
  --green-mid:#10B981;
  --green-light:#D1FAE5;
  --green-pale:#ECFDF5;
  /* Support colors */
  --amber:#FEF3C7;
  --amber-mid:#FCD34D;
  --sky:#E0F2FE;
  --sky-mid:#38BDF8;
  --orange:#F97316;
  --dark:#111827;
  --mid:#6B7280;
  --soft:#9CA3AF;
  --white:#ffffff;
  --gray-bg:#F3F4F6;
  --gray-line:#E5E7EB;
  --gray-hairline:#F0F0F0;
  /* Elevation */
  --shadow-sm:0 1px 3px rgba(15,23,42,.06);
  --shadow-md:0 4px 16px rgba(15,23,42,.08);
  --shadow-lg:0 12px 40px rgba(15,23,42,.10);
  --shadow-brand:0 8px 24px rgba(5,150,105,.18);
  --radius:14px;
  --radius-sm:10px;
  --radius-lg:20px;
  --tap:44px; /* minimum touch target */
}

body{
  font-family:'DM Sans',system-ui,-apple-system,'Segoe UI',Roboto,sans-serif;
  background:#E7EAF0;
  min-height:100vh;
  display:flex;
  justify-content:center;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  color:var(--dark);
}

/* ── PAGE WRAPPER ── */
.page-wrapper{
  width:100%;max-width:900px;
  background:var(--white);
  border-radius:0;
  overflow:hidden;
  box-shadow:var(--shadow-lg);
  margin:0 auto;
  padding-bottom:env(safe-area-inset-bottom);
}

/* ── NAV ── */
nav.site-nav{
  position:sticky;top:0;z-index:100;
  background:rgba(255,255,255,.92);
  backdrop-filter:saturate(180%) blur(14px);
  -webkit-backdrop-filter:saturate(180%) blur(14px);
  padding:10px 16px;
  padding-top:calc(10px + env(safe-area-inset-top));
  display:flex;align-items:center;justify-content:space-between;
  gap:8px;
  border-bottom:1px solid var(--gray-hairline);
  min-height:var(--tap);
}
.nav-logo{
  display:flex;align-items:center;gap:10px;
  font-weight:800;font-size:17px;color:var(--navy);
  text-decoration:none;letter-spacing:-.01em;
}
.nav-logo-icon{
  width:32px;height:32px;border-radius:8px;
  background:var(--navy);
  display:flex;align-items:center;justify-content:center;
  box-shadow:0 2px 6px rgba(11,37,69,.25);
  flex-shrink:0;
}
.nav-links{display:flex;gap:22px;align-items:center;}
.nav-links a{
  font-size:14px;color:var(--mid);text-decoration:none;font-weight:500;
  padding:8px 4px;transition:color .15s;
}
.nav-links a:hover,.nav-links a:focus-visible{color:var(--navy);}
.nav-cta{
  font-size:13px;font-weight:600;
  padding:10px 18px;border-radius:999px;
  background:var(--navy);color:var(--white);
  text-decoration:none;transition:transform .15s, box-shadow .15s, background .15s;
  display:inline-flex;align-items:center;gap:6px;
  min-height:40px;white-space:nowrap;
}
.nav-cta:hover,.nav-cta:focus-visible{
  background:var(--navy-tint);transform:translateY(-1px);
  box-shadow:0 6px 18px rgba(11,37,69,.22);
}

/* Mobile menu toggle (checkbox-driven, no JS required) */
.nav-toggle{display:none;}
.nav-burger{
  display:none;
  width:var(--tap);height:var(--tap);
  align-items:center;justify-content:center;
  border-radius:10px;cursor:pointer;
  color:var(--navy);
  -webkit-tap-highlight-color:transparent;
}
.nav-burger:hover{background:var(--gray-bg);}
.nav-burger svg{width:22px;height:22px;}
.nav-burger .icon-close{display:none;}
.nav-toggle:checked ~ .nav-burger .icon-open{display:none;}
.nav-toggle:checked ~ .nav-burger .icon-close{display:block;}

/* ── CONTENT AREA ── */
.content-area{padding:28px 20px;}

/* ── TYPOGRAPHY (CONTENT PAGES) ── */
.content-area h1{
  font-size:clamp(24px,4.2vw,30px);font-weight:800;line-height:1.2;
  color:var(--navy);margin-bottom:10px;
  letter-spacing:-.02em;
}
.content-area h2{
  font-size:clamp(20px,3vw,24px);font-weight:700;line-height:1.25;
  color:var(--navy);margin:28px 0 12px;
  letter-spacing:-.01em;
}
.content-area h3{
  font-size:17px;font-weight:700;line-height:1.3;
  color:var(--green-dark);margin:22px 0 8px;
}
.content-area h4{
  font-size:15px;font-weight:700;color:var(--dark);
  margin:16px 0 8px;
}
.content-area p{
  font-size:15px;color:#374151;line-height:1.75;
  margin-bottom:14px;
}
.content-area a{
  color:var(--green-dark);text-decoration:underline;
  text-decoration-color:rgba(5,150,105,.35);
  text-underline-offset:3px;
  transition:all .15s;
}
.content-area a:hover,.content-area a:focus-visible{
  color:var(--green);text-decoration-color:var(--green);
}
.content-area strong{color:var(--navy);}
.content-area ul,.content-area ol{
  margin:0 0 16px 22px;
  font-size:15px;color:#374151;line-height:1.75;
}
.content-area li{margin-bottom:6px;}
.content-area li::marker{color:var(--green);}

/* ── BREADCRUMB ── */
.breadcrumb{font-size:12px;color:var(--mid);margin-bottom:14px;}
.breadcrumb a{color:var(--mid);text-decoration:none;}
.breadcrumb a:hover{color:var(--green);}

/* ── HERO BANNER (inner pages) ── */
.page-hero{
  padding:28px 20px 22px;
  background:
    radial-gradient(ellipse at 20% 50%,rgba(5,150,105,.10) 0%,transparent 60%),
    radial-gradient(ellipse at 80% 50%,rgba(11,37,69,.08) 0%,transparent 60%),
    var(--white);
  border-bottom:1px solid var(--gray-hairline);
}
.page-hero h1{
  font-size:clamp(26px,5vw,34px);font-weight:800;line-height:1.15;
  color:var(--navy);margin-bottom:10px;letter-spacing:-.02em;
}
.page-hero .subtitle{
  font-size:15px;color:var(--mid);line-height:1.6;
  max-width:560px;
}
.page-hero .breadcrumb{margin-bottom:12px;}

/* ── CARDS ── */
.card{
  background:var(--gray-bg);border-radius:var(--radius);
  padding:20px;margin-bottom:16px;transition:transform .2s;
}
.card:hover{transform:translateY(-1px);}
.card-green{background:var(--green-pale);border-radius:var(--radius);padding:20px;margin-bottom:16px;}
.card-amber{background:var(--amber);border-radius:var(--radius);padding:20px;margin-bottom:16px;}
.card-sky{background:var(--sky);border-radius:var(--radius);padding:20px;margin-bottom:16px;}

/* ── TABLES ── */
.content-area table{
  width:100%;border-collapse:collapse;
  margin:16px 0;font-size:13px;
  border-radius:var(--radius-sm);
  overflow:hidden;
}
.content-area thead th{
  background:var(--navy);color:var(--white);
  padding:11px 14px;text-align:left;
  font-weight:600;font-size:12px;letter-spacing:.02em;
}
.content-area tbody td{
  padding:11px 14px;border-bottom:1px solid var(--gray-hairline);
  color:#374151;
}
.content-area tbody tr:hover{background:var(--green-pale);}
.content-area tbody tr:last-child td{border-bottom:none;}

/* ── TABLE BOX ── */
.table-box{
  background:var(--white);
  border:1px solid var(--gray-line);
  padding:0;border-radius:var(--radius);
  margin:20px 0;overflow-x:auto;
  -webkit-overflow-scrolling:touch;
}
.table-box table{margin:0;}

/* ── HIGHLIGHT / CALLOUT ── */
.highlight-box{
  background:var(--green-pale);
  border-left:4px solid var(--green);
  padding:16px 20px;margin:20px 0;
  border-radius:0 var(--radius-sm) var(--radius-sm) 0;
  font-size:15px;color:#374151;line-height:1.7;
}
.highlight-box strong{color:var(--navy);}

/* ── CTA BOX ── */
.cta-box{
  background:linear-gradient(135deg,var(--navy) 0%,var(--navy-tint) 100%);
  border-radius:var(--radius);
  padding:26px 22px;margin:24px 0;
  text-align:center;color:var(--white);
  position:relative;overflow:hidden;
}
.cta-box::before{
  content:"";position:absolute;inset:0;
  background:radial-gradient(circle at 85% 20%,rgba(5,150,105,.35) 0%,transparent 55%);
  pointer-events:none;
}
.cta-box>*{position:relative;}
.cta-box h3,.cta-box h2{color:var(--white);margin-bottom:8px;}
.cta-box p{color:rgba(255,255,255,.85);font-size:14px;margin-bottom:16px;}
.cta-box .btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:12px 24px;border-radius:999px;
  background:var(--green);color:var(--white);
  font-size:14px;font-weight:700;text-decoration:none;
  transition:transform .15s, box-shadow .15s;
  border:none;cursor:pointer;min-height:var(--tap);
  box-shadow:var(--shadow-brand);
}
.cta-box .btn:hover,.cta-box .btn:focus-visible{
  transform:translateY(-2px);
  box-shadow:0 12px 28px rgba(5,150,105,.3);
}

/* ── FAQ ── */
.faq-section{margin:24px 0;}
.faq-section h2{margin-bottom:16px;}
.faq-item{
  padding:14px 0;border-bottom:1px solid var(--gray-hairline);
  cursor:pointer;
}
.faq-question{
  display:flex;justify-content:space-between;align-items:center;
  font-size:15px;font-weight:600;color:var(--navy);
  min-height:var(--tap);
}
.faq-icon{font-size:22px;color:var(--green);font-weight:300;flex-shrink:0;transition:transform .25s;}
.faq-item.active .faq-icon{transform:rotate(45deg);}
.faq-answer{
  max-height:0;overflow:hidden;
  transition:max-height .3s ease, padding .3s ease;
  font-size:14px;color:var(--mid);line-height:1.75;
}
.faq-item.active .faq-answer{max-height:800px;padding-top:10px;}

/* ── DOWNLOAD BUTTONS ── */
.download-btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:12px 22px;border-radius:999px;
  font-size:14px;font-weight:600;
  text-decoration:none;transition:all .15s;
  border:1px solid var(--gray-line);color:var(--navy);
  background:var(--white);min-height:var(--tap);
}
.download-btn:hover,.download-btn:focus-visible{
  border-color:var(--green);background:var(--green-pale);
  transform:translateY(-1px);text-decoration:none;
}
.download-btn.primary{
  background:var(--green);color:var(--white);border-color:var(--green);
  box-shadow:var(--shadow-brand);
}
.download-btn.primary:hover{background:var(--green-dark);}

/* ── INVOICE PREVIEW ── */
.invoice{
  background:var(--white);
  border:1px solid var(--gray-line);
  border-radius:var(--radius);
  padding:20px;margin:20px 0;font-size:12px;
}
.invoice-header{
  display:flex;justify-content:space-between;align-items:flex-start;
  margin-bottom:16px;padding-bottom:12px;
  border-bottom:2px solid var(--green);
}
.invoice-title{font-size:16px;font-weight:800;color:var(--navy);}
.invoice-subtitle{font-size:11px;color:var(--mid);}
.invoice-details{
  display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-bottom:16px;
}
.invoice-detail-item{font-size:11px;color:#374151;}
.invoice-detail-item strong{color:var(--navy);font-size:11px;}
.invoice-items{margin:16px 0;}
.invoice-item{
  display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:8px;
  padding:6px 0;font-size:11px;color:#374151;
  border-bottom:1px solid var(--gray-hairline);
}
.invoice-item.header{font-weight:700;color:var(--navy);border-bottom:2px solid var(--navy);}
.invoice-item.total{font-weight:700;color:var(--navy);border-top:2px solid var(--navy);border-bottom:none;}
.breakdown{margin-top:12px;}
.breakdown-item{display:flex;justify-content:space-between;font-size:11px;padding:3px 0;color:#374151;}
.breakdown-item.total{font-weight:700;color:var(--navy);border-top:1px solid var(--navy);padding-top:6px;}

/* ── BLOG LISTING ── */
.blog-grid{display:grid;grid-template-columns:1fr;gap:12px;}
.blog-card{
  background:var(--gray-bg);border-radius:var(--radius);
  padding:18px;transition:transform .2s, box-shadow .2s;
  text-decoration:none;display:block;
}
.blog-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-md);text-decoration:none;}
.blog-card h3{font-size:16px;color:var(--navy);margin:0 0 6px;}
.blog-card p{font-size:13px;color:var(--mid);margin:0;line-height:1.6;}

/* ── PRICING ── */
.pricing-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:16px 0;}
.pricing-card{border-radius:var(--radius);padding:20px;transition:transform .25s, box-shadow .25s;}
.pricing-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-md);}
.pricing-card.light{background:var(--gray-bg);color:var(--navy);}
.pricing-card.dark{background:var(--navy);color:var(--white);}
.plan-name{font-size:14px;font-weight:700;margin-bottom:2px;}
.plan-sub{font-size:10px;color:var(--mid);margin-bottom:12px;}
.pricing-card.dark .plan-sub{color:#9CA3AF;}
.price{margin-bottom:14px;}
.price-amount{font-size:28px;font-weight:800;}
.price-period{font-size:11px;color:var(--mid);}
.pricing-card.dark .price-period{color:#9CA3AF;}
.plan-features{list-style:none;margin:0 0 16px;padding:0;}
.plan-features li{font-size:11px;padding:3px 0;display:flex;align-items:center;gap:6px;}
.plan-features li::marker{content:none;}
.check-icon{width:14px;height:14px;flex-shrink:0;color:var(--green);}
.pricing-card.dark .check-icon{color:#34D399;}

/* ── FOOTER ── */
footer.site-footer{
  padding:24px 20px;
  border-top:1px solid var(--gray-hairline);
  padding-bottom:calc(24px + env(safe-area-inset-bottom));
}
.footer-top{
  display:flex;justify-content:space-between;align-items:flex-start;
  flex-wrap:wrap;gap:16px;margin-bottom:12px;
}
.footer-brand{max-width:280px;}
.footer-desc{font-size:12px;color:var(--mid);line-height:1.6;margin-top:8px;margin-bottom:10px;}
.footer-seo{font-size:10px;color:var(--soft);line-height:1.6;margin-bottom:10px;}
.social-row{display:flex;gap:8px;}
.social-icon{
  width:36px;height:36px;border-radius:10px;
  background:var(--gray-bg);
  display:flex;align-items:center;justify-content:center;
  color:var(--mid);transition:all .15s;cursor:pointer;
  text-decoration:none;
}
.social-icon:hover{background:var(--green-light);color:var(--green-dark);}
.social-icon svg{width:14px;height:14px;}
.footer-links{display:grid;grid-template-columns:1fr 1fr;gap:6px 24px;}
.footer-links a{font-size:12px;color:var(--mid);text-decoration:none;transition:color .15s;padding:4px 0;}
.footer-links a:hover{color:var(--green);}
.footer-bottom{
  text-align:center;padding-top:12px;
  border-top:1px solid var(--gray-hairline);
  font-size:11px;color:var(--soft);
}

/* ── ACCESSIBILITY ── */
:focus-visible{outline:3px solid rgba(5,150,105,.4);outline-offset:2px;border-radius:4px;}
@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important;}
}

/* ── ANIMATIONS ── */
@keyframes fadeUp{from{opacity:0;transform:translateY(20px);}to{opacity:1;transform:translateY(0);}}
@keyframes fadeIn{from{opacity:0;}to{opacity:1;}}

/* ── SCROLL REVEAL ── */
.sr{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s ease;}
.sr.visible{opacity:1;transform:none;}

/* ══════════════════════════════════════════════════════════
   RESPONSIVE — mobile-first overrides
   ══════════════════════════════════════════════════════════ */

/* Mobile ≤ 600px */
@media (max-width:600px){
  .page-wrapper{border-radius:0;}

  /* Hide desktop links — they move into the drawer */
  .nav-links{
    display:none;
    position:absolute;top:100%;left:0;right:0;
    background:var(--white);
    flex-direction:column;align-items:stretch;
    gap:0;padding:8px 12px 16px;
    border-bottom:1px solid var(--gray-hairline);
    box-shadow:var(--shadow-md);
  }
  .nav-links a{
    padding:14px 10px;font-size:15px;
    border-bottom:1px solid var(--gray-hairline);
    min-height:var(--tap);display:flex;align-items:center;
  }
  .nav-links a:last-child{border-bottom:none;}
  .nav-toggle:checked ~ .nav-links{display:flex;}
  .nav-burger{display:inline-flex;}
  .nav-cta{padding:8px 14px;font-size:12.5px;}

  .content-area{padding:22px 16px;}
  .page-hero{padding:22px 16px 18px;}
  .content-area h1,.page-hero h1{font-size:24px;}
  .content-area h2{font-size:20px;}
  .content-area p,.content-area ul,.content-area ol{font-size:15px;}

  .pricing-grid{grid-template-columns:1fr 1fr;}
  .invoice-details{grid-template-columns:1fr;}
  .footer-top{flex-direction:column;}
  .footer-links{grid-template-columns:1fr 1fr;}

  .cta-box{padding:22px 18px;}
  .cta-box .btn{width:100%;justify-content:center;}

  /* Prevent iOS auto-zoom on input focus */
  input,select,textarea{font-size:16px !important;}
}

/* Narrow Android (≤ 380px) */
@media (max-width:380px){
  .content-area{padding:18px 14px;}
  .page-hero{padding:18px 14px 14px;}
  .nav-logo{font-size:15px;}
  .nav-logo-icon{width:28px;height:28px;}
  .pricing-grid{grid-template-columns:1fr;}
  .footer-links{grid-template-columns:1fr;}
}

/* Tablet (601–899px) */
@media (min-width:601px) and (max-width:899px){
  .content-area{padding:32px 28px;}
  .page-hero{padding:32px 28px 26px;}
  .pricing-grid{grid-template-columns:1fr 1fr;}
  .blog-grid{grid-template-columns:1fr 1fr;gap:14px;}
}

/* Desktop ≥ 900px */
@media (min-width:900px){
  .page-wrapper{max-width:1100px;border-radius:0;box-shadow:none;}
  body{background:var(--white);}
  .content-area{padding:48px 72px;max-width:900px;margin:0 auto;}
  .page-hero{padding:48px 72px 36px;}
  .page-hero h1,.content-area h1{font-size:36px;}
  .content-area h2{font-size:26px;}
  .content-area p,.content-area ul,.content-area ol{font-size:16px;}
  .content-area table{font-size:14px;}
  .content-area thead th{font-size:13px;padding:13px 16px;}
  .content-area tbody td{padding:13px 16px;}
  nav.site-nav{padding:14px 64px;}
  footer.site-footer{padding:36px 64px;}
  .footer-top{gap:32px;}
  .footer-links{grid-template-columns:1fr 1fr 1fr;gap:8px 32px;}
  .pricing-grid{grid-template-columns:repeat(4,1fr);}
  .blog-grid{grid-template-columns:1fr 1fr;gap:16px;}
  .features-grid{gap:16px;}
  .faq-question{font-size:16px;}
  .faq-answer{font-size:15px;}
  .cta-box{padding:36px;}
  .cta-box p{font-size:15px;}
  .highlight-box{font-size:16px;}
}

/* Large desktop ≥ 1200px */
@media (min-width:1200px){
  .page-wrapper{max-width:1200px;}
  .content-area{padding:56px 88px;}
}