/* ============ Tokens ============ */
:root{
  --bg: #f5f3ee;
  --bg-alt: #ffffff;
  --surface: #ffffff;
  --surface-2: #eeece5;
  --border: #ddd9cf;
  --text: #1b1d1f;
  --text-muted: #5b5e63;
  --accent: #c96a2e;
  --accent-strong: #a8501d;
  --accent-soft: #f2ddc9;
  --teal: #2c8f74;
  --danger: #c0392b;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow: 0 8px 30px rgba(20,18,14,0.08);
  --header-h: 68px;
  --font-display: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
}

[data-theme="dark"]{
  --bg: #12151a;
  --bg-alt: #0d0f13;
  --surface: #1a1e25;
  --surface-2: #20242c;
  --border: #2b303a;
  --text: #eceef1;
  --text-muted: #9aa1ac;
  --accent: #e8974b;
  --accent-strong: #f2ab68;
  --accent-soft: #3a2c1c;
  --teal: #4ac9a0;
  --shadow: 0 8px 30px rgba(0,0,0,0.4);
}

*,*::before,*::after{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:var(--font-body);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  transition:background .25s ease, color .25s ease;
  overflow-x:hidden;
}
h1,h2,h3{font-family:var(--font-display); margin:0 0 .5em; letter-spacing:-0.01em;}
p{margin:0 0 1em;}
a{color:inherit;}
img{max-width:100%;display:block;}
.skip-link{position:absolute;left:-999px;top:0;background:var(--accent);color:#fff;padding:10px 16px;z-index:2000;border-radius:0 0 8px 0;}
.skip-link:focus{left:0;}

/* ============ Buttons ============ */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.4em;
  border:1px solid transparent;border-radius:999px;
  padding:.65em 1.4em;font-weight:600;font-size:.95rem;cursor:pointer;
  font-family:var(--font-body);transition:transform .15s ease, box-shadow .15s ease, background .2s ease, opacity .2s;
  text-decoration:none;
}
.btn:active{transform:scale(.97);}
.btn-primary{background:var(--accent);color:#fff;}
.btn-primary:hover{background:var(--accent-strong);}
.btn-ghost{background:transparent;color:var(--text);border-color:var(--border);}
.btn-ghost:hover{background:var(--surface-2);}
.btn-outline-light{background:transparent;color:#fff;border-color:rgba(255,255,255,.5);}
.btn-outline-light:hover{background:rgba(255,255,255,.12);}
.btn-lg{padding:.85em 1.9em;font-size:1rem;}
.btn:disabled{opacity:.6;cursor:not-allowed;}
.btn-spinner{display:none;width:16px;height:16px;border:2px solid rgba(255,255,255,.4);border-top-color:#fff;border-radius:50%;animation:spin .7s linear infinite;}
.btn.loading .btn-spinner{display:inline-block;}
.btn.loading .btn-text{opacity:.7;}
@keyframes spin{to{transform:rotate(360deg);}}

/* ============ Cookie Banner ============ */
.cookie-banner{
  position:fixed;left:16px;right:16px;bottom:16px;max-width:640px;margin:0 auto;
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);
  padding:16px 20px;box-shadow:var(--shadow);z-index:1500;
  display:flex;flex-wrap:wrap;gap:12px;align-items:center;justify-content:space-between;
  transform:translateY(140%);transition:transform .4s ease;
}
.cookie-banner.show{transform:translateY(0);}
.cookie-banner p{margin:0;font-size:.88rem;color:var(--text-muted);flex:1 1 240px;}
.cookie-banner a{color:var(--accent);text-decoration:underline;}
.cookie-actions{display:flex;gap:8px;}

/* ============ Header ============ */
.site-header{
  position:sticky;top:0;z-index:1000;background:var(--bg-alt);
  border-bottom:1px solid var(--border);height:var(--header-h);
}
.header-inner{
  max-width:1280px;margin:0 auto;height:100%;padding:0 20px;
  display:flex;align-items:center;justify-content:space-between;gap:16px;
}
.brand{display:flex;align-items:center;gap:8px;text-decoration:none;color:var(--text);}
.brand-mark{color:var(--accent);display:flex;}
.brand-name{font-family:var(--font-display);font-weight:700;font-size:1.15rem;white-space:nowrap;}
.brand-dot{color:var(--accent);}

.main-nav ul{list-style:none;display:flex;gap:4px;margin:0;padding:0;align-items:center;}
.main-nav li{position:relative;}
.nav-link{
  background:none;border:none;color:var(--text);font:inherit;font-size:.92rem;font-weight:500;
  padding:10px 12px;border-radius:8px;cursor:pointer;display:flex;align-items:center;gap:4px;
  text-decoration:none;
}
.nav-link:hover{background:var(--surface-2);}
.chev{transition:transform .2s ease;}
.has-mega[aria-expanded="true"] .chev, .has-mega .nav-link[aria-expanded="true"] .chev{transform:rotate(180deg);}

.mega-panel{
  position:absolute;top:100%; /* required: not calc(100% + 8px) */
  left:0;min-width:520px;background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius-md);box-shadow:var(--shadow);
  padding:18px;display:none;grid-template-columns:1fr 1fr;gap:8px 24px;z-index:1100;
}
.has-mega.open .mega-panel{display:grid;}
.mega-col{display:flex;flex-direction:column;gap:2px;}
.mega-col a{
  padding:8px 10px;border-radius:8px;text-decoration:none;color:var(--text-muted);font-size:.88rem;
}
.mega-col a:hover{background:var(--surface-2);color:var(--text);}

.header-actions{display:flex;align-items:center;gap:6px;}
.icon-btn{
  background:none;border:1px solid var(--border);width:38px;height:38px;border-radius:999px;
  display:flex;align-items:center;justify-content:center;cursor:pointer;color:var(--text);
}
.icon-btn:hover{background:var(--surface-2);}
.icon-moon{display:none;}
[data-theme="dark"] .icon-sun{display:none;}
[data-theme="dark"] .icon-moon{display:block;}

.hamburger{display:none;flex-direction:column;gap:4px;background:none;border:none;cursor:pointer;padding:8px;}
.hamburger span{width:22px;height:2px;background:var(--text);border-radius:2px;transition:.25s;}

/* ============ Breadcrumb ============ */
.breadcrumb{background:var(--surface-2);border-bottom:1px solid var(--border);}
.breadcrumb-inner{
  max-width:1280px;margin:0 auto;padding:10px 20px;font-size:.82rem;color:var(--text-muted);
  display:flex;gap:8px;align-items:center;flex-wrap:wrap;
}
.breadcrumb-inner a{text-decoration:none;color:var(--text-muted);}
.breadcrumb-inner a:hover{color:var(--accent);}
.breadcrumb-inner [aria-current]{color:var(--text);font-weight:500;}

/* ============ Hero ============ */
.hero{padding:64px 20px 40px;background:linear-gradient(180deg, var(--surface-2), var(--bg));}
.hero-inner{max-width:1280px;margin:0 auto;display:grid;grid-template-columns:1.1fr .9fr;gap:48px;align-items:center;}
.eyebrow{display:inline-block;font-size:.78rem;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--accent);background:var(--accent-soft);padding:6px 12px;border-radius:999px;margin-bottom:14px;}
.hero h1{font-size:clamp(2.2rem,4.5vw,3.4rem);}
.hero-sub{font-size:1.08rem;color:var(--text-muted);max-width:52ch;}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap;margin:20px 0 18px;}
.hero-trust{display:flex;gap:16px;flex-wrap:wrap;font-size:.82rem;color:var(--text-muted);}

.disk-array{display:flex;flex-direction:column;gap:10px;}
.disk-row{display:flex;gap:6px;}
.disk-block{
  flex:1;height:34px;border-radius:6px;display:flex;align-items:center;justify-content:center;
  font-size:.65rem;font-weight:700;color:#fff;opacity:0;transform:translateY(6px);
  animation:blockIn .5s ease forwards;
}
@keyframes blockIn{to{opacity:1;transform:translateY(0);}}
.dot-data,.blk-data{background:var(--teal);}
.dot-parity,.blk-parity{background:var(--accent);}
.dot-mirror,.blk-mirror{background:#6f7de0;}
.dot{width:11px;height:11px;border-radius:3px;display:inline-block;margin-right:6px;}

/* ============ Reference strip ============ */
.ref-strip{background:var(--surface);border-top:1px solid var(--border);border-bottom:1px solid var(--border);}
.ref-inner{max-width:1280px;margin:0 auto;padding:22px 20px;}
.ref-label{font-size:.85rem;color:var(--text-muted);margin-bottom:10px;}
.ref-links{display:flex;flex-wrap:wrap;gap:8px;}
.ref-links a{
  font-size:.8rem;padding:6px 12px;border:1px solid var(--border);border-radius:999px;
  text-decoration:none;color:var(--text-muted);white-space:nowrap;
}
.ref-links a:hover{border-color:var(--accent);color:var(--accent);}

/* ============ Calculator ============ */
.calc-section{padding:64px 20px;}
.calc-inner{max-width:920px;margin:0 auto;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:36px;box-shadow:var(--shadow);}
.field-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-top:20px;}
.field{display:flex;flex-direction:column;gap:6px;}
.field label{font-size:.86rem;font-weight:600;}
.opt-label{font-weight:400;color:var(--text-muted);font-size:.8rem;}
.field input,.field select{
  padding:11px 14px;border-radius:var(--radius-sm);border:1px solid var(--border);
  background:var(--bg-alt);color:var(--text);font:inherit;font-size:.94rem;width:100%;
}
.field input:focus,.field select:focus,.field input:focus-visible{outline:2px solid var(--accent);outline-offset:1px;}
.input-with-unit{display:flex;gap:8px;}
.input-with-unit select{max-width:90px;}
.hint{font-size:.76rem;color:var(--text-muted);}
.error-msg{font-size:.78rem;color:var(--danger);min-height:1em;}
.field.invalid input, .field.invalid select{border-color:var(--danger);}
.range-row{display:flex;align-items:center;gap:12px;}
.range-row input[type="range"]{flex:1;}
.range-row span{font-size:.8rem;color:var(--text-muted);white-space:nowrap;min-width:150px;text-align:right;}

.form-actions{display:flex;gap:12px;margin-top:28px;flex-wrap:wrap;}
.form-note{font-size:.78rem;color:var(--text-muted);margin-top:16px;}

/* ============ Results ============ */
.result-section{padding:20px 20px 70px;}
.result-inner{max-width:1000px;margin:0 auto;}
.result-sub{color:var(--text-muted);}
.result-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:16px;margin:24px 0 36px;}
.result-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);padding:20px;}
.result-card .rc-label{font-size:.78rem;color:var(--text-muted);text-transform:uppercase;letter-spacing:.04em;margin-bottom:6px;}
.result-card .rc-value{font-family:var(--font-display);font-size:1.5rem;font-weight:700;}
.result-card .rc-sub{font-size:.78rem;color:var(--text-muted);margin-top:4px;}
.result-card.warn{border-color:var(--danger);}

.array-diagram-wrap{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);padding:28px;}
.diagram-legend{display:flex;gap:20px;font-size:.82rem;color:var(--text-muted);margin-top:16px;flex-wrap:wrap;}

.result-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:28px;}
.copy-toast{
  margin-top:12px;font-size:.85rem;color:var(--teal);opacity:0;transition:opacity .3s ease;height:1.2em;
}
.copy-toast.show{opacity:1;}

/* ============ SEO content ============ */
.seo-content{padding:20px 20px 60px;}
.seo-content-inner{max-width:820px;margin:0 auto;color:var(--text-muted);font-size:.98rem;}
.seo-content-inner h2{color:var(--text);}

/* ============ Features ============ */
.features{padding:60px 20px;background:var(--surface-2);}
.features-inner{max-width:1280px;margin:0 auto;}
.feature-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:20px;margin-top:28px;}
.feature-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);padding:24px;}
.feature-icon{font-size:1.6rem;margin-bottom:10px;}
.feature-card h3{font-size:1.05rem;}
.feature-card p{color:var(--text-muted);font-size:.9rem;margin:0;}

/* ============ How it works ============ */
.how-it-works{padding:64px 20px;}
.how-inner{max-width:900px;margin:0 auto;}
.how-steps{list-style:none;margin:28px 0 0;padding:0;display:flex;flex-direction:column;gap:22px;}
.how-steps li{display:flex;gap:18px;align-items:flex-start;}
.step-num{
  flex:none;width:36px;height:36px;border-radius:50%;background:var(--accent);color:#fff;
  display:flex;align-items:center;justify-content:center;font-weight:700;font-family:var(--font-display);
}
.how-steps h3{font-size:1.05rem;margin-bottom:.2em;}
.how-steps p{color:var(--text-muted);margin:0;}

/* ============ FAQ ============ */
.faq{padding:60px 20px;background:var(--surface-2);}
.faq-inner{max-width:820px;margin:0 auto;}
.faq-item{border-bottom:1px solid var(--border);}
.faq-q{
  width:100%;text-align:left;background:none;border:none;padding:18px 4px;font:inherit;font-weight:600;
  cursor:pointer;display:flex;justify-content:space-between;align-items:center;color:var(--text);
}
.faq-chev{transition:transform .2s ease;flex:none;margin-left:12px;}
.faq-q[aria-expanded="true"] .faq-chev{transform:rotate(180deg);}
.faq-a{max-height:0;overflow:hidden;transition:max-height .25s ease;}
.faq-a p{padding:0 4px 18px;color:var(--text-muted);margin:0;}

/* ============ CTA ============ */
.cta{padding:70px 20px;background:linear-gradient(135deg,var(--accent-strong),var(--accent));color:#fff;text-align:center;}
.cta-inner{max-width:700px;margin:0 auto;}
.cta h2{color:#fff;}
.cta p{color:rgba(255,255,255,.9);}
.cta-actions{display:flex;gap:14px;justify-content:center;flex-wrap:wrap;margin-top:20px;}

/* ============ Footer ============ */
.site-footer{background:var(--bg-alt);border-top:1px solid var(--border);padding:50px 20px 20px;}
.footer-inner{max-width:1280px;margin:0 auto;display:grid;grid-template-columns:260px 1fr;gap:40px;}
.footer-brand p{color:var(--text-muted);font-size:.88rem;}
.footer-cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:16px;}
.footer-col h4{font-size:.82rem;text-transform:uppercase;letter-spacing:.04em;color:var(--text-muted);margin:0 0 10px;}
.footer-col a{display:block;font-size:.85rem;text-decoration:none;color:var(--text);padding:4px 0;}
.footer-col a:hover{color:var(--accent);}
.footer-bottom{max-width:1280px;margin:30px auto 0;padding-top:20px;border-top:1px solid var(--border);font-size:.78rem;color:var(--text-muted);display:flex;flex-wrap:wrap;gap:16px;justify-content:space-between;align-items:center;}
.footer-legal{display:flex;gap:14px;flex-wrap:wrap;}
.footer-legal a{text-decoration:none;color:var(--text-muted);}
.footer-legal a:hover{color:var(--accent);}

/* ============ Responsive ============ */
@media (max-width: 960px){
  .hero-inner{grid-template-columns:1fr;gap:32px;}
  .field-grid{grid-template-columns:1fr;}
  .footer-inner{grid-template-columns:1fr;}
}

@media (max-width: 780px){
  .main-nav{
    position:fixed;top:var(--header-h);left:0;right:0;bottom:0;background:var(--bg-alt);
    padding:16px 20px;overflow-y:auto;transform:translateX(100%);transition:transform .3s ease;
    z-index:999;
  }
  .main-nav.open{transform:translateX(0);}
  .main-nav ul{flex-direction:column;align-items:stretch;gap:2px;width:100%;}
  .nav-link{width:100%;justify-content:space-between;}
  .mega-panel{position:static;min-width:0;box-shadow:none;border:none;padding:8px 0 8px 16px;grid-template-columns:1fr;}
  .hamburger{display:flex;}
  .hamburger.open span:nth-child(1){transform:translateY(6px) rotate(45deg);}
  .hamburger.open span:nth-child(2){opacity:0;}
  .hamburger.open span:nth-child(3){transform:translateY(-6px) rotate(-45deg);}
}

@media (max-width: 480px){
  html,body{max-width:100vw;overflow-x:hidden;}
  .header-inner{padding:0 14px;}
  .brand-name{font-size:1rem;}
  .hero{padding:44px 14px 30px;}
  .calc-inner{padding:22px;}
  .cookie-banner{left:10px;right:10px;bottom:10px;padding:14px;}
  .result-actions{flex-direction:column;}
  .result-actions .btn{width:100%;}
}

@media (prefers-reduced-motion: reduce){
  *{animation-duration:.01ms !important; animation-iteration-count:1 !important; transition-duration:.01ms !important; scroll-behavior:auto !important;}
}