/* ============================================================
   MEP Professionals' Society of Bangladesh — Design System
   Navy-dominant, engineering-grade, restrained discipline accents
   ============================================================ */

/* ---------- Tokens ---------- */
:root{
  /* Brand navy scale */
  --navy-900:#1c2937;
  --navy-800:#243343;
  --navy-700:#2c3e50;   /* primary brand */
  --navy-600:#3a4f63;
  --navy-500:#4d6377;

  /* Ink & neutrals (cool-toned) */
  --ink:#1f2b36;
  --slate:#56697a;
  --slate-2:#7e8e9c;
  --line:#e3e8ed;
  --line-2:#eef2f5;
  --bg:#ffffff;
  --bg-soft:#f6f8fa;
  --bg-softer:#f0f4f7;

  /* Discipline accents (shared chroma/lightness, varied hue) */
  --mech:#c07c2f;       --mech-ink:#8f5a1d;  --mech-soft:#f7efe3;  --mech-line:#ecdcc4;
  --elec:#2f7cb8;       --elec-ink:#225f90;  --elec-soft:#e9f1f8;  --elec-line:#cfe1ef;
  --plumb:#2a948a;      --plumb-ink:#1f6f68;  --plumb-soft:#e6f2f0; --plumb-line:#c8e4df;

  /* Type */
  --font-head:'Archivo','Helvetica Neue',Arial,sans-serif;
  --font-body:'IBM Plex Sans','Helvetica Neue',Arial,sans-serif;
  --font-mono:ui-monospace,'SF Mono','SFMono-Regular',Menlo,Consolas,monospace;

  /* Spacing / radius / shadow */
  --r-sm:7px; --r-md:12px; --r-lg:18px;
  --shadow-sm:0 1px 2px rgba(28,41,55,.05),0 1px 3px rgba(28,41,55,.06);
  --shadow-md:0 4px 14px rgba(28,41,55,.07),0 2px 6px rgba(28,41,55,.05);
  --shadow-lg:0 18px 50px -12px rgba(28,41,55,.20);
  --maxw:1200px;
}

/* ---------- Reset ---------- */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:84px;-webkit-text-size-adjust:100%}
body{
  font-family:var(--font-body);
  color:var(--ink);
  background:var(--bg);
  line-height:1.6;
  font-size:17px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;border:none;background:none}
ul{list-style:none}
::selection{background:var(--navy-700);color:#fff}

/* ---------- Typography ---------- */
h1,h2,h3,h4,h5{font-family:var(--font-head);color:var(--navy-800);line-height:1.12;letter-spacing:-.01em;font-weight:800}
h1{font-size:clamp(2.2rem,5vw,3.5rem)}
h2{font-size:clamp(1.7rem,3.2vw,2.5rem)}
h3{font-size:clamp(1.2rem,2vw,1.5rem);font-weight:700}
h4{font-size:1.05rem;font-weight:700}
p{text-wrap:pretty}
.lead{font-size:clamp(1.05rem,1.6vw,1.3rem);color:var(--slate);line-height:1.55;font-weight:400}

.eyebrow{
  font-family:var(--font-mono);
  font-size:.74rem;letter-spacing:.18em;text-transform:uppercase;
  color:var(--slate-2);font-weight:500;display:inline-flex;align-items:center;gap:.6em;
}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--slate-2);display:inline-block}
.eyebrow.center::before{display:none}

/* ---------- Layout ---------- */
.container{max-width:var(--maxw);margin:0 auto;padding:0 clamp(20px,4vw,40px)}
.container-wide{max-width:1340px;margin:0 auto;padding:0 clamp(20px,4vw,40px)}
section{position:relative}
.section{padding:clamp(64px,9vw,120px) 0}
.section-soft{background:var(--bg-soft)}
.section-navy{background:var(--navy-800);color:#fff}
.section-head{max-width:760px;margin-bottom:clamp(36px,5vw,60px)}
.section-head.center{margin-left:auto;margin-right:auto;text-align:center}
.section-head h2{margin:14px 0 0}
.section-head p{margin-top:16px}
.grid{display:grid;gap:24px}
.cols-2{grid-template-columns:repeat(2,1fr)}
.cols-3{grid-template-columns:repeat(3,1fr)}
.cols-4{grid-template-columns:repeat(4,1fr)}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.6em;
  font-family:var(--font-body);font-weight:600;font-size:.97rem;
  padding:13px 24px;border-radius:var(--r-sm);
  transition:transform .15s ease,background .2s ease,box-shadow .2s ease,color .2s ease;
  white-space:nowrap;
}
.btn:active{transform:translateY(1px)}
.btn-primary{background:var(--navy-700);color:#fff;box-shadow:var(--shadow-sm)}
.btn-primary:hover{background:var(--navy-800);box-shadow:var(--shadow-md)}
.btn-ghost{background:transparent;color:var(--navy-700);box-shadow:inset 0 0 0 1.5px var(--line)}
.btn-ghost:hover{box-shadow:inset 0 0 0 1.5px var(--navy-700);background:var(--bg-soft)}
.btn-on-navy{background:#fff;color:var(--navy-800)}
.btn-on-navy:hover{background:var(--bg-softer)}
.btn-ghost-navy{box-shadow:inset 0 0 0 1.5px rgba(255,255,255,.4);color:#fff}
.btn-ghost-navy:hover{box-shadow:inset 0 0 0 1.5px #fff;background:rgba(255,255,255,.08)}
.btn-lg{padding:16px 30px;font-size:1.03rem}
.btn .arrow{transition:transform .2s ease}
.btn:hover .arrow{transform:translateX(3px)}

/* ---------- Tags / badges ---------- */
.tag{
  display:inline-flex;align-items:center;gap:.4em;
  font-family:var(--font-mono);font-size:.7rem;font-weight:500;letter-spacing:.06em;
  text-transform:uppercase;padding:4px 9px;border-radius:5px;
  background:var(--bg-softer);color:var(--slate);
}
.tag-dot{width:7px;height:7px;border-radius:50%;background:var(--slate-2)}
.tag.m{background:var(--mech-soft);color:var(--mech-ink)}   .tag.m .tag-dot{background:var(--mech)}
.tag.e{background:var(--elec-soft);color:var(--elec-ink)}   .tag.e .tag-dot{background:var(--elec)}
.tag.p{background:var(--plumb-soft);color:var(--plumb-ink)} .tag.p .tag-dot{background:var(--plumb)}

/* ---------- Cards ---------- */
.card{
  background:#fff;border:1px solid var(--line);border-radius:var(--r-md);
  box-shadow:var(--shadow-sm);transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease;
}
.card:hover{box-shadow:var(--shadow-md)}
.card-pad{padding:26px}

/* corner-tick decoration */
.ticked{position:relative}
.ticked::before,.ticked::after{
  content:"";position:absolute;width:10px;height:10px;pointer-events:none;
}
.ticked::before{top:10px;left:10px;border-top:1.5px solid var(--line);border-left:1.5px solid var(--line)}
.ticked::after{bottom:10px;right:10px;border-bottom:1.5px solid var(--line);border-right:1.5px solid var(--line)}

/* ---------- Header ---------- */
.site-header{
  position:sticky;top:0;z-index:80;background:rgba(255,255,255,.92);
  backdrop-filter:saturate(180%) blur(12px);
  border-bottom:1px solid var(--line);
}
.header-inner{display:flex;align-items:center;gap:24px;height:84px}
.brand{display:flex;align-items:center;gap:12px;flex-shrink:0}
.brand img{height:54px;width:auto}
.brand .brand-text{display:none}
.main-nav{display:flex;align-items:center;gap:2px;margin-left:auto}
.main-nav a{
  font-size:.86rem;font-weight:500;color:var(--slate);padding:8px 11px;border-radius:6px;
  transition:color .15s ease,background .15s ease;white-space:nowrap;position:relative;
}
.main-nav a:hover{color:var(--navy-800);background:var(--bg-soft)}
.main-nav a.active{color:var(--navy-800);font-weight:600}
.main-nav a.active::after{
  content:"";position:absolute;left:11px;right:11px;bottom:1px;height:2px;border-radius:2px;
  background:var(--navy-700);
}
.header-cta{display:flex;align-items:center;gap:10px;flex-shrink:0}
.header-cta .btn{padding:10px 18px;font-size:.86rem}
.nav-toggle{display:none;width:42px;height:42px;border-radius:8px;align-items:center;justify-content:center;color:var(--navy-800)}
.nav-toggle:hover{background:var(--bg-soft)}
.nav-toggle svg{width:24px;height:24px}

/* mobile drawer */
.mobile-nav{
  position:fixed;inset:0 0 0 auto;width:min(86vw,360px);background:#fff;z-index:100;
  transform:translateX(100%);transition:transform .3s cubic-bezier(.4,0,.2,1);
  box-shadow:var(--shadow-lg);display:flex;flex-direction:column;padding:24px;overflow-y:auto;
}
.mobile-nav.open{transform:translateX(0)}
.mobile-nav .mn-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}
.mobile-nav a{padding:14px 12px;border-radius:8px;font-weight:500;color:var(--navy-800);border-bottom:1px solid var(--line-2)}
.mobile-nav a:hover{background:var(--bg-soft)}
.mobile-nav a.active{color:var(--navy-700);font-weight:700}
.nav-scrim{position:fixed;inset:0;background:rgba(28,41,55,.4);z-index:99;opacity:0;visibility:hidden;transition:.3s}
.nav-scrim.open{opacity:1;visibility:visible}

/* ---------- Footer ---------- */
.site-footer{background:var(--navy-900);color:#cdd6df}
.footer-top{padding:64px 0 48px;display:grid;grid-template-columns:1.4fr 1fr 1fr 1.2fr;gap:40px}
.site-footer .f-logo img{height:58px;margin-bottom:18px}
.site-footer p{font-size:.92rem;color:#9fb0bd;line-height:1.7}
.footer-col h5{font-family:var(--font-mono);font-size:.74rem;letter-spacing:.16em;text-transform:uppercase;color:#7e93a3;font-weight:500;margin-bottom:18px}
.footer-col a{display:block;font-size:.93rem;color:#c2cdd6;padding:6px 0;transition:color .15s,padding-left .15s}
.footer-col a:hover{color:#fff;padding-left:4px}
.f-contact li{font-size:.92rem;color:#9fb0bd;padding:5px 0;display:flex;gap:10px}
.f-contact li svg{width:16px;height:16px;flex-shrink:0;margin-top:4px;color:#6f8595}
.footer-bottom{border-top:1px solid rgba(255,255,255,.09);padding:22px 0;display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap}
.footer-bottom p{font-size:.84rem;color:#7e93a3}
.reg-note{font-family:var(--font-mono);font-size:.76rem;letter-spacing:.04em;color:#8ea0af}

/* ---------- Utilities ---------- */
.text-center{text-align:center}
.mono{font-family:var(--font-mono)}
.muted{color:var(--slate)}
.divider{height:1px;background:var(--line);border:0}
.reveal{opacity:0;transform:translateY(18px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  *{scroll-behavior:auto!important}
  .reveal{opacity:1;transform:none;transition:none}
}

/* ---------- Image placeholder ---------- */
.ph{
  background:
    repeating-linear-gradient(135deg,var(--bg-softer) 0 11px,#e8edf1 11px 22px);
  display:flex;align-items:center;justify-content:center;text-align:center;
  color:var(--slate-2);font-family:var(--font-mono);font-size:.72rem;letter-spacing:.04em;
  border:1px dashed var(--line);border-radius:var(--r-sm);padding:14px;
}
.ph span{background:rgba(255,255,255,.75);padding:4px 9px;border-radius:4px}

/* ---------- Responsive base ---------- */
@media (max-width:1080px){
  .main-nav{display:none}
  .nav-toggle{display:flex}
  .header-cta .btn-member{display:none}
  .footer-top{grid-template-columns:1fr 1fr}
}
@media (max-width:760px){
  body{font-size:16px}
  .cols-2,.cols-3,.cols-4{grid-template-columns:1fr}
  .footer-top{grid-template-columns:1fr;gap:30px;padding:48px 0 36px}
  .footer-bottom{flex-direction:column;align-items:flex-start}
}