/* ==========================================================
   CalcLabHub — Base Stylesheet
   Project: calclabhub.com
   ========================================================== */

:root {
  --color-bg: #ffffff;
  --color-surface: #f8fafc;
  --color-surface-2: #f1f5f9;
  --color-text: #0f172a;
  --color-text-2: #475569;
  --color-text-muted: #94a3b8;
  --color-border: #e2e8f0;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-soft: #dbeafe;
  --color-success: #10b981;
  --color-warn: #f59e0b;
  --color-danger: #ef4444;

  --cat-finance: #047857;
  --cat-finance-soft: #ecfdf5;
  --cat-math: #1d4ed8;
  --cat-math-soft: #dbeafe;
  --cat-converters: #b45309;
  --cat-converters-soft: #fef3c7;
  --cat-ai: #6d28d9;
  --cat-ai-soft: #ede9fe;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.06);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}
img, svg { max-width: 100%; display: block; }
a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  width: 100%;
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 1rem;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}
.site-header__inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 60px; gap: 1rem;
}
.site-header__brand {
  display: flex; align-items: center; gap: 0.6rem;
  font-weight: 700; color: var(--color-text); font-size: 1.05rem;
}
.site-header__brand:hover { text-decoration: none; }
.site-header__brand-mark {
  display: inline-flex; align-items: center; justify-content: center;
  width: 34px; height: 34px; border-radius: 8px;
  background: linear-gradient(135deg, #2563eb, #6d28d9);
  color: #fff; font-weight: 800; font-size: 0.95rem;
  letter-spacing: -0.02em;
}
.site-header__nav { display: flex; gap: 1rem; font-size: 0.92rem; flex-wrap: wrap; }
.site-header__nav a { color: var(--color-text-2); font-weight: 500; }
.site-header__nav a:hover { color: var(--color-primary); text-decoration: none; }

/* ---------- Hero (homepage) ---------- */
.hero {
  padding: 3.5rem 0 2rem;
  text-align: center;
  background: radial-gradient(ellipse at top, var(--color-primary-soft) 0%, transparent 60%);
}
.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3rem);
  margin: 0 0 0.6rem;
  letter-spacing: -0.02em;
}
.hero__sub {
  font-size: 1.15rem;
  color: var(--color-text-2);
  max-width: 700px;
  margin: 0 auto 1.5rem;
}
.hero__cta {
  display: flex; gap: 0.7rem; justify-content: center; flex-wrap: wrap;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 0.7rem 1.4rem;
  border-radius: var(--radius-md);
  font-weight: 600; font-size: 0.95rem;
  cursor: pointer;
  border: 1px solid transparent;
  text-align: center;
  transition: all 0.15s ease;
  font-family: inherit;
}
.btn--primary { background: var(--color-primary); color: #fff; }
.btn--primary:hover { background: var(--color-primary-hover); text-decoration: none; }
.btn--secondary { background: var(--color-surface); color: var(--color-text); border-color: var(--color-border); }
.btn--secondary:hover { border-color: var(--color-primary); color: var(--color-primary); }
.btn--lg { padding: 0.85rem 1.6rem; font-size: 1rem; }

/* ---------- Category Grid ---------- */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}
.cat-card {
  display: flex; align-items: center; gap: 1rem;
  padding: 1.3rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none; color: inherit;
  transition: all 0.15s ease;
}
.cat-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}
.cat-card__icon {
  width: 50px; height: 50px;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-md);
  font-size: 1.5rem; font-weight: 700;
}
.cat-finance    .cat-card__icon { background: var(--cat-finance-soft); color: var(--cat-finance); }
.cat-math       .cat-card__icon { background: var(--cat-math-soft); color: var(--cat-math); }
.cat-converters .cat-card__icon { background: var(--cat-converters-soft); color: var(--cat-converters); }
.cat-ai         .cat-card__icon { background: var(--cat-ai-soft); color: var(--cat-ai); }
.cat-card__title { margin: 0 0 0.2rem; font-size: 1.05rem; font-weight: 700; }
.cat-card__desc { margin: 0; font-size: 0.85rem; color: var(--color-text-2); }
.cat-card__count {
  display: inline-block;
  font-size: 0.72rem; font-weight: 700;
  margin-top: 0.4rem;
  padding: 0.15rem 0.5rem;
  border-radius: 99px;
  color: var(--color-text-muted);
  background: var(--color-surface-2);
}
.cat-finance    .cat-card__count { background: var(--cat-finance-soft); color: var(--cat-finance); }
.cat-math       .cat-card__count { background: var(--cat-math-soft); color: var(--cat-math); }
.cat-converters .cat-card__count { background: var(--cat-converters-soft); color: var(--cat-converters); }
.cat-ai         .cat-card__count { background: var(--cat-ai-soft); color: var(--cat-ai); }
.cat-text       .cat-card__count { background: var(--cat-text-soft); color: var(--cat-text); }
.cat-health     .cat-card__count { background: var(--cat-health-soft); color: var(--cat-health); }

/* ---------- Section heads ---------- */
.section-head {
  display: flex; align-items: baseline; justify-content: space-between;
  margin: 2.5rem 0 1rem;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 0.5rem;
  gap: 1rem; flex-wrap: wrap;
}
.section-head h2 { margin: 0; font-size: 1.4rem; }
.section-head p { margin: 0; color: var(--color-text-2); font-size: 0.95rem; }

/* ---------- Tool grid & cards ---------- */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}
.tool-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.3rem;
  transition: all 0.15s ease;
  text-decoration: none; color: inherit;
  display: flex; flex-direction: column;
}
.tool-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}
.tool-card__icon {
  width: 40px; height: 40px;
  display: flex; align-items: center; justify-content: center;
  background: var(--color-primary-soft);
  color: var(--color-primary);
  border-radius: var(--radius-md);
  font-size: 1.3rem; font-weight: 700;
  margin-bottom: 0.7rem;
}
.tool-card__title { margin: 0 0 0.3rem; font-size: 1.05rem; font-weight: 700; }
.tool-card__desc { color: var(--color-text-2); font-size: 0.9rem; margin: 0; flex: 1; }
.tool-card__cta {
  margin-top: 0.8rem;
  color: var(--color-primary); font-weight: 600; font-size: 0.9rem;
}

/* ---------- Tool page layout ---------- */
.tool-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 1.75rem;
  margin: 1.5rem 0;
}
@media (max-width: 900px) {
  .tool-layout { grid-template-columns: 1fr; }
  .tool-sidebar { order: -1; display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; }
}
@media (max-width: 600px) {
  .tool-sidebar { grid-template-columns: 1fr; }
}
.tool-main { min-width: 0; }
.tool-sidebar { display: flex; flex-direction: column; gap: 1rem; }

.tool-intro {
  margin-bottom: 1rem;
}
.tool-intro h1 {
  font-size: clamp(1.7rem, 4vw, 2.1rem);
  margin: 0 0 0.5rem;
  letter-spacing: -0.02em;
}
.tool-intro p { font-size: 1.02rem; color: var(--color-text-2); margin: 0; }

.cat-tag {
  display: inline-block;
  font-size: 0.78rem; font-weight: 700;
  padding: 0.2rem 0.6rem;
  border-radius: 99px;
  margin-bottom: 0.5rem;
}
.cat-tag.cat-finance    { background: var(--cat-finance-soft); color: var(--cat-finance); }
.cat-tag.cat-math       { background: var(--cat-math-soft); color: var(--cat-math); }
.cat-tag.cat-converters { background: var(--cat-converters-soft); color: var(--cat-converters); }
.cat-tag.cat-ai         { background: var(--cat-ai-soft); color: var(--cat-ai); }

/* ---------- Card ---------- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.4rem;
  margin: 1rem 0;
}

/* ---------- Form ---------- */
.tool-form {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}
.field { display: flex; flex-direction: column; gap: 0.3rem; }
.field--full { grid-column: 1 / -1; }
.field__label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
}
.field__hint { font-size: 0.78rem; color: var(--color-text-muted); }
.input, .select {
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-family: inherit;
  background: var(--color-bg);
  color: var(--color-text);
  width: 100%;
  transition: border-color 0.15s ease;
}
.input:focus, .select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-soft);
}
.input-group {
  display: flex; align-items: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-bg);
}
.input-group:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-soft);
}
.input-group .input { border: 0; box-shadow: none; }
.input-group__suffix {
  padding: 0 0.75rem;
  font-size: 0.85rem;
  color: var(--color-text-2);
  background: var(--color-surface-2);
  border-left: 1px solid var(--color-border);
  align-self: stretch;
  display: flex; align-items: center;
}
.tool-form__actions {
  grid-column: 1 / -1;
  display: flex; gap: 0.6rem; flex-wrap: wrap;
}

/* ---------- Result ---------- */
.tool-result {
  margin-top: 1rem;
  padding: 1.25rem;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-primary-soft), #f0fdf4);
  border: 1px solid var(--color-primary);
}
.tool-result__primary {
  font-size: 2rem;
  font-weight: 800;
  color: var(--color-primary);
  margin: 0.4rem 0 0.8rem;
  letter-spacing: -0.02em;
}
.tool-result__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.6rem;
  margin: 0;
}
.tool-result__item {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  padding: 0.7rem 0.9rem;
}
.tool-result__item dt {
  font-size: 0.78rem;
  color: var(--color-text-2);
  margin-bottom: 0.2rem;
}
.tool-result__item dd {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 0;
}
.result-row {
  display: flex; justify-content: space-between;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--color-border);
}
.result-row:last-child { border-bottom: 0; }
.result-row strong { color: var(--color-text); }
.result-row span { color: var(--color-text-2); font-family: var(--font-mono); }
.swatch {
  width: 100%;
  height: 120px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

/* ---------- Article (long-form content) ---------- */
.article-content h2 {
  font-size: 1.4rem;
  margin: 1.75rem 0 0.6rem;
}
.article-content h3 {
  font-size: 1.15rem;
  margin: 1.25rem 0 0.4rem;
}
.article-content p { margin: 0 0 0.9rem; }
.article-content ul, .article-content ol {
  padding-left: 1.5rem;
  margin: 0 0 0.9rem;
}
.article-content li { margin: 0.3rem 0; }
.article-content strong { color: var(--color-text); }
.article-content code {
  background: var(--color-surface-2);
  padding: 0.1rem 0.4rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.92em;
}

/* ---------- FAQ ---------- */
.faq { display: grid; gap: 0.6rem; margin-top: 0.6rem; }
.faq__item {
  background: var(--color-surface-2);
  border-radius: var(--radius-md);
  padding: 0.8rem 1rem;
}
.faq__q { margin: 0 0 0.3rem; font-weight: 600; font-size: 0.95rem; }
.faq__a { margin: 0; color: var(--color-text-2); font-size: 0.92rem; }

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  font-size: 0.85rem;
  color: var(--color-text-2);
  margin: 1rem 0;
}
.breadcrumb a { color: var(--color-text-2); }
.breadcrumb a:hover { color: var(--color-primary); }
.breadcrumb span { margin: 0 0.3rem; opacity: 0.5; }

/* ---------- Ad slots ---------- */
/* ADS HIDDEN BY DEFAULT — keep markup, hide visuals.
   To enable (e.g. when integrating AdSense / Ezoic / Mediavine):
     1. Delete the `.ad-slot{display:none!important}` line below
     2. Uncomment the original .ad-slot block that follows
*/
.ad-slot { display: none !important; }

/* ----- ORIGINAL AD-SLOT STYLES (commented out) -----
.ad-slot {
  margin: 1rem 0;
  padding: 0.8rem;
  background: var(--color-surface-2);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-md);
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.78rem;
  min-height: 80px;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 0.3rem;
}
.ad-slot::before {
  content: "Advertisement";
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}
.ad-slot::after {
  content: attr(data-size);
  font-size: 0.7rem;
  opacity: 0.7;
}
.ad-top        { min-height: 100px; }
.ad-inarticle  { min-height: 100px; }
.ad-sidebar    { min-height: 270px; }
.ad-sidebar-tall { min-height: 620px; }
.ad-footer     { min-height: 100px; }
.ad-mobile     { min-height: 110px; display: none; }
@media (max-width: 768px) {
  .ad-mobile { display: flex; }
}
----- END ORIGINAL AD-SLOT STYLES ----- */

/* ---------- Footer ---------- */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  margin-top: 3rem;
  padding: 2rem 0 1rem;
}
.site-footer__inner {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 2rem;
}
.site-footer h4 { margin: 0 0 0.5rem; font-size: 0.95rem; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin: 0.3rem 0; }
.site-footer a { color: var(--color-text-2); font-size: 0.9rem; }
.site-footer a:hover { color: var(--color-primary); }
.site-footer__bottom {
  text-align: center;
  padding-top: 1.5rem;
  margin-top: 1.5rem;
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

/* ---------- Utilities ---------- */
.text-muted { color: var(--color-text-muted); }
.text-center { text-align: center; }
.hidden { display: none !important; }
.mt-0 { margin-top: 0 !important; }
.mb-1 { margin-bottom: 0.5rem !important; }
.mb-2 { margin-bottom: 1rem !important; }

/* ---------- Scientific Calculator special ---------- */
.sci-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.4rem;
  max-width: 480px;
  margin: 1rem auto;
}
.sci-btn {
  padding: 1rem 0.5rem;
  font-size: 1.05rem;
  font-weight: 600;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text);
  cursor: pointer;
  font-family: inherit;
  transition: background 0.1s ease;
}
.sci-btn:hover { background: var(--color-surface); }
.sci-btn--op  { background: var(--color-primary-soft); color: var(--color-primary); }
.sci-btn--eq  { background: var(--color-primary); color: #fff; }
.sci-btn--fn  { background: var(--color-surface-2); }
.sci-display {
  grid-column: 1 / -1;
  padding: 1rem;
  background: var(--color-surface-2);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: 1.5rem;
  text-align: right;
  min-height: 70px;
  display: flex; flex-direction: column; justify-content: center;
  border: 1px solid var(--color-border);
  margin-bottom: 0.4rem;
}
.sci-display__secondary { font-size: 0.9rem; color: var(--color-text-muted); }

/* ---------- Currency converter ---------- */
.cur-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr auto;
  gap: 0.6rem;
  align-items: end;
  margin-bottom: 0.6rem;
}
@media (max-width: 600px) {
  .cur-row { grid-template-columns: 1fr 1fr; }
  .cur-row .swap { grid-column: span 2; }
}
.swap {
  width: 40px; height: 40px;
  border-radius: 99px;
  background: var(--color-primary);
  color: #fff;
  border: 0;
  font-size: 1.2rem;
  cursor: pointer;
}

/* ---------- Image-to-Base64 etc ---------- */
.dropzone {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  text-align: center;
  background: var(--color-surface);
  transition: all 0.18s ease;
  cursor: pointer;
}
.dropzone:hover { border-color: var(--color-primary); background: var(--color-primary-soft); }
.dropzone strong { color: var(--color-primary); }

/* ---------- Tool index/category page ---------- */
.cat-page-hero {
  padding: 2.5rem 0 1rem;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 1.5rem;
}
.cat-page-hero h1 {
  margin: 0.4rem 0 0.4rem;
  font-size: clamp(1.8rem, 4vw, 2.3rem);
}
.cat-page-hero p {
  color: var(--color-text-2);
  font-size: 1.02rem;
  max-width: 720px;
  margin: 0;
}

/* ---------- Blog grid ---------- */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}
.blog-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.3rem;
  text-decoration: none; color: inherit;
  transition: all 0.15s ease;
  display: flex; flex-direction: column;
}
.blog-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}
.blog-card__title { margin: 0 0 0.4rem; font-size: 1.02rem; }
.blog-card__desc { margin: 0 0 0.7rem; color: var(--color-text-2); font-size: 0.88rem; flex: 1; }
.blog-card__cta { color: var(--color-primary); font-weight: 600; font-size: 0.85rem; }

/* ---------- Why grid (homepage) ---------- */
.why-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}
.why-item {
  display: flex; gap: 0.8rem; align-items: flex-start;
}
.why-check {
  width: 28px; height: 28px;
  flex-shrink: 0;
  border-radius: 99px;
  background: var(--color-success);
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 0.85rem;
}
.why-item h3 { margin: 0 0 0.2rem; font-size: 0.98rem; }
.why-item p { margin: 0; color: var(--color-text-2); font-size: 0.88rem; }

/* ---------- Ad inline (footer sticky on mobile) ---------- */
@media (max-width: 768px) {
  .hero { padding: 2rem 0 1.5rem; }
  .hero__cta .btn { width: 100%; }
}