/* ===== Asphalt Calculator — Global Stylesheet ===== */
:root{
  --color-bg:#ffffff;
  --color-surface:#f7f7f5;
  --color-surface-alt:#eeece4;
  --color-text:#1a1a1a;
  --color-text-muted:#555;
  --color-border:#dcd9d0;
  --color-primary:#d35400;
  --color-primary-dark:#a8420a;
  --color-accent:#2c3e50;
  --color-success:#1f8a4c;
  --radius:8px;
  --shadow-sm:0 1px 2px rgba(0,0,0,.06);
  --shadow-md:0 4px 12px rgba(0,0,0,.08);
  --max-width:1100px;
  --font-body:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --font-heading:Georgia,"Times New Roman",serif;
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.65;
  color:var(--color-text);
  background:var(--color-bg);
}

img{max-width:100%;height:auto;display:block}
a{color:var(--color-primary-dark);text-decoration:none}
a:hover,a:focus{text-decoration:underline}

h1,h2,h3,h4,h5,h6{
  font-family:var(--font-heading);
  line-height:1.25;
  color:var(--color-accent);
  margin:1.6em 0 .6em;
}
h1{font-size:2rem;margin-top:.4em}
h2{font-size:1.55rem;border-bottom:2px solid var(--color-surface-alt);padding-bottom:.3em}
h3{font-size:1.2rem}
h4{font-size:1.05rem;color:var(--color-text)}
p,ul,ol,table{margin:.6em 0 1em}
ul,ol{padding-left:1.4em}
li{margin:.25em 0}

/* ===== Header ===== */
.site-header{
  background:var(--color-accent);
  color:#fff;
  border-bottom:3px solid var(--color-primary);
}
.header-inner{
  max-width:var(--max-width);
  margin:0 auto;
  padding:.9rem 1rem;
  display:flex;
  align-items:center;
  justify-content:space-between;
  flex-wrap:wrap;
  gap:.8rem;
}
.brand{
  font-family:var(--font-heading);
  font-size:1.25rem;
  font-weight:700;
  color:#fff;
}
.brand:hover{text-decoration:none;color:#f4d03f}
.brand-mark{
  display:inline-block;width:28px;height:28px;background:var(--color-primary);
  border-radius:4px;margin-right:.5rem;vertical-align:middle;position:relative;
}
.brand-mark::after{
  content:"";position:absolute;left:5px;right:5px;top:12px;height:3px;
  background:repeating-linear-gradient(90deg,#fff 0 4px,transparent 4px 8px);
}

/* ===== Nav ===== */
.main-nav ul{
  list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:.2rem;
}
.main-nav a{
  display:block;padding:.5rem .8rem;color:#fff;border-radius:4px;font-size:.95rem;
}
.main-nav a:hover,.main-nav a:focus,.main-nav a.active{
  background:rgba(255,255,255,.12);text-decoration:none;
}

.lang-switch{font-size:.85rem}
.lang-switch a{color:#f4d03f;margin:0 .25rem}

/* ===== Layout ===== */
main{display:block}
.container{max-width:var(--max-width);margin:0 auto;padding:1.5rem 1rem 3rem}
.hero{
  background:linear-gradient(135deg,#2c3e50 0%,#1a252f 100%);
  color:#fff;padding:2.5rem 1rem;text-align:center;
}
.hero h1{color:#fff;font-size:2.2rem;margin:.2em auto;max-width:800px}
.hero p{max-width:720px;margin:0 auto;font-size:1.1rem;opacity:.92}

/* ===== Calculator Tool ===== */
.calc-wrap{
  background:var(--color-surface);
  border:1px solid var(--color-border);
  border-radius:var(--radius);
  padding:1.5rem;
  margin:1.5rem 0 2rem;
  box-shadow:var(--shadow-md);
}
.calc-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:1.5rem;
}
.calc-form label{
  display:block;font-weight:600;margin:.8rem 0 .3rem;font-size:.95rem;
}
.calc-form input,.calc-form select{
  width:100%;padding:.6rem .7rem;border:1px solid var(--color-border);
  border-radius:4px;font-size:1rem;font-family:inherit;background:#fff;
}
.calc-form input:focus,.calc-form select:focus{
  outline:2px solid var(--color-primary);outline-offset:1px;border-color:var(--color-primary);
}
.unit-row{display:flex;gap:.5rem;align-items:center;margin-bottom:1rem}
.unit-row label{margin:0;font-weight:500;font-size:.9rem}
.btn{
  display:inline-block;background:var(--color-primary);color:#fff;border:none;
  padding:.75rem 1.4rem;border-radius:4px;font-size:1rem;font-weight:600;
  cursor:pointer;font-family:inherit;
}
.btn:hover,.btn:focus{background:var(--color-primary-dark);text-decoration:none;color:#fff}
.btn-secondary{
  background:transparent;color:var(--color-primary-dark);
  border:2px solid var(--color-primary-dark);
}
.btn-secondary:hover{background:var(--color-primary-dark);color:#fff}
.btn-row{margin-top:1.2rem;display:flex;gap:.6rem;flex-wrap:wrap}

.calc-results{
  background:#fff;border:1px solid var(--color-border);border-radius:var(--radius);
  padding:1.2rem;
}
.calc-results h3{margin-top:0;color:var(--color-primary-dark)}
.result-item{
  display:flex;justify-content:space-between;align-items:baseline;
  padding:.6rem 0;border-bottom:1px dashed var(--color-border);
}
.result-item:last-child{border-bottom:none}
.result-label{font-size:.95rem;color:var(--color-text-muted)}
.result-value{font-size:1.3rem;font-weight:700;color:var(--color-accent);font-family:var(--font-heading)}
.result-value.highlight{color:var(--color-primary);font-size:1.6rem}
.calc-note{font-size:.85rem;color:var(--color-text-muted);margin-top:1rem;padding-top:.8rem;border-top:1px solid var(--color-border)}

/* ===== Tables ===== */
table{border-collapse:collapse;width:100%;margin:1rem 0;font-size:.95rem}
th,td{padding:.6rem .8rem;text-align:left;border-bottom:1px solid var(--color-border)}
th{background:var(--color-surface-alt);font-weight:700}
tbody tr:nth-child(even){background:var(--color-surface)}

/* ===== Callouts ===== */
.callout{
  background:#fff8e1;border-left:4px solid #f4a020;padding:.9rem 1rem;
  border-radius:0 var(--radius) var(--radius) 0;margin:1.2rem 0;
}
.callout-info{background:#e3f2fd;border-left-color:#1976d2}
.callout-success{background:#e8f5e9;border-left-color:var(--color-success)}
.callout strong{display:block;margin-bottom:.3em}

/* ===== FAQ ===== */
.faq details{
  background:var(--color-surface);border:1px solid var(--color-border);
  border-radius:var(--radius);padding:.8rem 1rem;margin:.6rem 0;
}
.faq summary{
  cursor:pointer;font-weight:600;font-family:var(--font-heading);font-size:1.05rem;
  color:var(--color-accent);
}
.faq details[open] summary{margin-bottom:.6rem}

/* ===== Cards / Related ===== */
.card-grid{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));
  gap:1rem;margin:1rem 0;
}
.card{
  background:#fff;border:1px solid var(--color-border);border-radius:var(--radius);
  padding:1.1rem;transition:box-shadow .15s,transform .15s;
}
.card:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}
.card h3{margin-top:0;font-size:1.1rem}
.card p{font-size:.9rem;color:var(--color-text-muted);margin:.4rem 0}

/* ===== Footer ===== */
.site-footer{
  background:#1a252f;color:#cfd6dc;padding:2rem 1rem 1rem;margin-top:3rem;
  font-size:.9rem;
}
.footer-inner{
  max-width:var(--max-width);margin:0 auto;
  display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:1.5rem;
}
.footer-col h4{color:#fff;font-size:1rem;margin:0 0 .6rem;font-family:var(--font-body)}
.footer-col ul{list-style:none;padding:0;margin:0}
.footer-col li{margin:.3rem 0}
.footer-col a{color:#cfd6dc}
.footer-col a:hover{color:#f4d03f}
.footer-bottom{
  max-width:var(--max-width);margin:1.5rem auto 0;padding-top:1rem;
  border-top:1px solid #2c3e50;text-align:center;font-size:.85rem;color:#8a96a0;
}

/* ===== Author / Meta ===== */
.page-meta{
  font-size:.85rem;color:var(--color-text-muted);margin:.5rem 0 1rem;
  padding:.5rem 0;border-top:1px solid var(--color-border);border-bottom:1px solid var(--color-border);
}
.page-meta span{margin-right:1rem}

/* ===== 404 ===== */
.error-page{text-align:center;padding:3rem 1rem}
.error-page h1{font-size:5rem;margin:.2em 0;color:var(--color-primary)}
.error-page p{font-size:1.1rem}

/* ===== Responsive ===== */
@media (max-width: 760px){
  .header-inner{flex-direction:column;align-items:flex-start}
  .main-nav ul{width:100%}
  .main-nav a{padding:.55rem .6rem;font-size:.9rem}
  .calc-grid{grid-template-columns:1fr}
  .hero h1{font-size:1.6rem}
  .hero p{font-size:1rem}
  h1{font-size:1.65rem}
  h2{font-size:1.3rem}
  .container{padding:1rem .8rem 2rem}
}

/* ===== Skip link / a11y ===== */
.skip-link{
  position:absolute;left:-9999px;top:auto;width:1px;height:1px;overflow:hidden;
}
.skip-link:focus{
  position:static;width:auto;height:auto;background:#fff;color:#000;
  padding:.5rem 1rem;display:inline-block;
}

/* ===== Print ===== */
@media print{
  .site-header,.site-footer,.btn,.btn-row{display:none}
  .calc-wrap{border:none;background:none;box-shadow:none}
}