/*
  Decisive Web Design — One-Page Light/Dark Theme
  - Drop-in stylesheet for the provided single-page index.html
  - Uses CSS variables for easy brand swapping
  - Includes: sticky glass header, mobile overlay nav, animated hero,
    grid sections, cards, forms, footer, and motion-safe fallbacks
*/

:root{
  /* ===== Brand tokens — update these to match your palette ===== */
  --brand-1:#0F172A;  /* primary text on light */
  --brand-2:#334155;  /* secondary text */
  --accent-1:#6EE7F2; /* CTA gradient start */
  --accent-2:#10B981; /* CTA gradient end */
  --bg-1:#F8FAFC;     /* page bg (light) */
  --bg-2:#FFFFFF;     /* surface (light) */
  --line:#E2E8F0;     /* hairlines */

  --radius-xl:1.2rem;
  --radius-md:.8rem;
  --shadow-1:0 10px 30px rgba(0,0,0,.08);
  --shadow-2:0 20px 60px rgba(0,0,0,.12);
  --speed-fast:160ms;
}

/* Dark mode overrides */
body.dark{
  --brand-1:#E5E7EB;
  --brand-2:#9CA3AF;
  --accent-1:#7DD3FC;
  --accent-2:#34D399;
  --bg-1:#0B1020;
  --bg-2:#0F172A;
  --line:#1F2A44;
}

/* ===== Base ===== */
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  background:var(--bg-1);
  color:var(--brand-1);
  font:16px/1.55 system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,Helvetica,Arial,"Apple Color Emoji","Segoe UI Emoji";
  letter-spacing:.2px;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}

h1,h2,h3{line-height:1.1;letter-spacing:-.02em;margin:0 0 .5rem 0}
h2{font-size:clamp(28px,3.4vw,40px)}
h3{font-size:clamp(18px,2.2vw,22px)}
p{margin:.25rem 0 1rem 0;color:var(--brand-2)}

.container{max-width:1200px;margin:0 auto;padding:0 22px}
.section{padding:72px 22px}

/* ===== Header / Nav ===== */
.header{
  position:sticky;top:0;z-index:50;
  display:flex;align-items:center;gap:20px;
  padding:14px 22px;
  backdrop-filter:saturate(180%) blur(12px);
  background:linear-gradient(to bottom, rgba(255,255,255,.65), rgba(255,255,255,.25));
  border-bottom:1px solid var(--line);
}
body.dark .header{background:linear-gradient(to bottom, rgba(11,16,32,.65), rgba(11,16,32,.25))}
.logo img{height:38px;width:auto}

.nav ul{list-style:none;display:flex;gap:22px;margin:0;padding:0}
.nav a{opacity:.9;font-weight:600}
.nav a:hover{opacity:1}

.actions{display:flex;gap:10px;margin-left:auto}
#mode-toggle{
  border:1px solid var(--line);
  background:var(--bg-2);
  color:var(--brand-1);
  padding:8px 12px;border-radius:999px;cursor:pointer;
  box-shadow:var(--shadow-1);
  transition:transform var(--speed-fast) ease;
}
#mode-toggle:hover{transform:translateY(-1px)}

/* Mobile Menu Button (hidden on desktop) */
#mobile-menu{display:none;border:1px solid var(--line);background:var(--bg-2);color:inherit;padding:8px 12px;border-radius:999px;cursor:pointer}

/* ===== Mobile Overlay Nav ===== */
@media (max-width: 768px){
  .nav{display:none}
  #mobile-menu{display:inline-flex}
  body.nav-open .nav{
    display:block;position:fixed;inset:72px 16px 16px 16px;z-index:60;
    background:rgba(3,6,20,.9);backdrop-filter:blur(10px);
    border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow-2);
    padding:18px;
  }
  body.dark.nav-open .nav{background:rgba(3,6,20,.9)}
  body.nav-open .nav ul{flex-direction:column;gap:12px}
  body.nav-open .nav a{color:#E5E7EB;font-size:18px}
}

/* ===== Hero ===== */
.hero{
  position:relative;min-height:clamp(72vh,88vh,100vh);
  display:grid;place-items:center;overflow:hidden;isolation:isolate;
}
/* Animated gradient background */
.hero::before{
  content:"";position:absolute;inset:-20%;z-index:-2;filter:blur(40px);
  background:
    radial-gradient(60% 60% at 20% 20%, rgba(110,231,242,.35) 0%, transparent 60%),
    radial-gradient(50% 50% at 80% 30%, rgba(52,211,153,.30) 0%, transparent 60%),
    linear-gradient(120deg, rgba(125,211,252,.15), rgba(16,185,129,.10));
  animation:gradientShift 16s ease-in-out infinite alternate;
}
/* Subtle grid overlay */
.hero::after{
  content:"";position:absolute;inset:0;z-index:-1;opacity:.06;
  background-image:linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size:40px 40px;
}
@keyframes gradientShift{0%{transform:translate3d(-4%,-2%,0) scale(1.05)}100%{transform:translate3d(4%,2%,0) scale(1.12)}}

.hero-content{text-align:center;padding:0 20px}
.hero h1{margin:0 0 10px 0;font-size:clamp(40px,7vw,84px)}
.hero p{margin:0 auto 26px;max-width:52ch;font-size:clamp(16px,2.2vw,20px);color:var(--brand-2)}

/* CTA */
.cta-btn{
  display:inline-block;padding:14px 22px;border-radius:var(--radius-xl);
  background:linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color:#051014;font-weight:800;box-shadow:var(--shadow-2);
  transform:translateY(0);transition:transform var(--speed-fast) ease, filter var(--speed-fast) ease;
}
.cta-btn:hover{transform:translateY(-2px);filter:saturate(115%)}

/* ===== Grid / Cards ===== */
.grid{display:grid;gap:22px}
.grid-3{grid-template-columns:repeat(3,1fr)}
@media (max-width: 1024px){.grid-3{grid-template-columns:1fr 1fr}}
@media (max-width: 640px){.grid-3{grid-template-columns:1fr}}

.card{
  background:var(--bg-2);border:1px solid var(--line);
  border-radius:var(--radius-md);box-shadow:var(--shadow-1);padding:22px;
}
figure.card{padding:0}
figure.card figcaption{padding:12px 16px;color:var(--brand-2)}

/* ===== Forms ===== */
input,textarea{width:100%;padding:12px 14px;border-radius:12px;border:1px solid var(--line);background:var(--bg-2);color:var(--brand-1)}
input:focus,textarea:focus{outline:none;box-shadow:0 0 0 3px rgba(125,211,252,.35)}
label{font-weight:600;color:var(--brand-1)}
button[type="submit"].cta-btn{border:none;cursor:pointer}

/* ===== Footer ===== */
footer{text-align:center;padding:32px 22px;border-top:1px solid var(--line);opacity:.85}

/* ===== Motion Safety ===== */
@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{animation:none!important;transition:none!important}
}