/* =============================================
   ToolHub Lite — Core Stylesheet
   Philosophy: system fonts, no framework, minimal
   CSS payload for maximum PageSpeed score.
   ============================================= */

:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-text: #1a1a2e;
  --color-text-light: #5b6072;
  --color-bg: #ffffff;
  --color-bg-alt: #f6f8fb;
  --color-border: #e5e8ef;
  --color-success: #16a34a;
  --radius: 10px;
  --max-width: 1120px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  font-size: 16px;
}

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

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- Header ---------- */
.site-header {
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  background: var(--color-bg);
  z-index: 100;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  padding-bottom: 14px;
}
.site-branding a {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--color-text);
  text-decoration: none;
}
.site-branding span { color: var(--color-primary); }

.primary-nav ul {
  list-style: none;
  display: flex;
  gap: 24px;
  margin: 0;
  padding: 0;
}
.primary-nav a {
  color: var(--color-text);
  font-weight: 500;
  font-size: 0.95rem;
}
.primary-nav a:hover { color: var(--color-primary); text-decoration: none; }

.menu-toggle { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; }

@media (max-width: 760px) {
  .primary-nav { display: none; }
  .primary-nav.is-open { display: block; width: 100%; }
  .primary-nav.is-open ul { flex-direction: column; gap: 4px; padding: 12px 0; }
  .menu-toggle { display: block; }
  .site-header .container { flex-wrap: wrap; }
}

/* ---------- Hero / Page header ---------- */
.page-hero {
  background: linear-gradient(180deg, var(--color-bg-alt) 0%, var(--color-bg) 100%);
  padding: 48px 0 32px;
  text-align: center;
}
.page-hero h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  margin: 0 0 12px;
}
.page-hero p {
  color: var(--color-text-light);
  max-width: 640px;
  margin: 0 auto;
  font-size: 1.05rem;
}
.breadcrumbs {
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-bottom: 10px;
}
.breadcrumbs a { color: var(--color-text-light); }

/* ---------- Tool grid (archive / homepage) ---------- */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 18px;
  padding: 40px 0;
}
.tool-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  background: var(--color-bg);
  transition: box-shadow .15s ease, transform .15s ease;
}
.tool-card:hover {
  box-shadow: 0 6px 20px rgba(20, 30, 60, 0.08);
  transform: translateY(-2px);
}
.tool-card .tool-icon { font-size: 1.8rem; margin-bottom: 8px; }
.tool-card h3 { margin: 0 0 6px; font-size: 1.05rem; }
.tool-card h3 a { color: var(--color-text); text-decoration: none; }
.tool-card p { margin: 0; font-size: 0.9rem; color: var(--color-text-light); }

.category-label {
  display: inline-block;
  background: var(--color-bg-alt);
  color: var(--color-primary);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 24px;
}

/* ---------- Tool app shell ---------- */
.tool-app {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  background: var(--color-bg-alt);
  margin: 20px 0 40px;
}
.tool-app .drop-zone {
  border: 2px dashed #c3cade;
  border-radius: var(--radius);
  padding: 40px 20px;
  text-align: center;
  cursor: pointer;
  background: var(--color-bg);
  transition: border-color .15s ease, background .15s ease;
}
.tool-app .drop-zone.is-dragover {
  border-color: var(--color-primary);
  background: #eef4ff;
}
.tool-app .drop-zone p { margin: 6px 0; color: var(--color-text-light); }
.tool-app input[type="file"] { display: none; }

.btn {
  display: inline-block;
  background: var(--color-primary);
  color: #fff;
  border: none;
  padding: 12px 22px;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s ease;
}
.btn:hover { background: var(--color-primary-dark); text-decoration: none; }
.btn:disabled { background: #a9b3c7; cursor: not-allowed; }
.btn-secondary {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text);
}
.btn-secondary:hover { background: var(--color-bg-alt); }

.file-list { list-style: none; padding: 0; margin: 16px 0; text-align: left; }
.file-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 12px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  margin-bottom: 6px;
  font-size: 0.9rem;
}
.file-list .remove-file { color: #dc2626; cursor: pointer; font-weight: 700; }

.result-box {
  margin-top: 20px;
  padding: 16px;
  border-radius: 8px;
  background: #ecfdf3;
  border: 1px solid #b7ebc6;
  display: none;
}
.result-box.is-visible { display: block; }
.result-box.is-error { background: #fef2f2; border-color: #fecaca; }

.form-row { margin-bottom: 16px; text-align: left; }
.form-row label { display: block; font-weight: 600; font-size: 0.9rem; margin-bottom: 6px; }
.form-row input, .form-row select {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 0.95rem;
  font-family: inherit;
}
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 600px) { .form-grid { grid-template-columns: 1fr; } }

.output-value {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--color-primary);
  margin: 4px 0;
}
.output-label { font-size: 0.85rem; color: var(--color-text-light); }
.output-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 16px; margin-top: 16px; }
.output-card { background: #fff; border: 1px solid var(--color-border); border-radius: 8px; padding: 14px 16px; }

.privacy-note {
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-top: 14px;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ---------- Content / article ---------- */
.content-area { padding: 20px 0 60px; }
.tool-description h2 { font-size: 1.3rem; margin-top: 40px; }
.faq-item { border-bottom: 1px solid var(--color-border); padding: 16px 0; }
.faq-item h3 { margin: 0 0 8px; font-size: 1rem; }
.faq-item p { margin: 0; color: var(--color-text-light); }

.related-tools ul { list-style: none; padding: 0; display: flex; flex-wrap: wrap; gap: 10px; }
.related-tools a {
  display: inline-block;
  background: var(--color-bg-alt);
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 0.85rem;
  color: var(--color-text);
}

/* ---------- Footer ---------- */
.site-footer {
  background: #101425;
  color: #c6cbdb;
  padding: 40px 0 20px;
  margin-top: 40px;
}
.site-footer a { color: #e5e8ef; }
.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 24px;
  margin-bottom: 24px;
}
.footer-grid h4 { color: #fff; font-size: 0.9rem; margin: 0 0 10px; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: 6px; font-size: 0.85rem; }
.footer-bottom {
  border-top: 1px solid #232a44;
  padding-top: 16px;
  font-size: 0.8rem;
  text-align: center;
  color: #8b91ac;
}

/* Accessibility */
.skip-link {
  position: absolute;
  left: -9999px;
  background: #000;
  color: #fff;
  padding: 10px 16px;
  z-index: 999;
}
.skip-link:focus { left: 10px; top: 10px; }