/* NetEngToolkit design system — professional, minimal, technical. */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;

  --radius: 8px;
  --radius-sm: 5px;
  --max-width: 1120px;

  --color-bg: #f7f8fa;
  --color-surface: #ffffff;
  --color-surface-alt: #f1f3f5;
  --color-border: #e1e4e8;
  --color-text: #1a1f27;
  --color-text-muted: #5b6472;
  --color-primary: #0a5cad;
  --color-primary-hover: #084a8a;
  --color-primary-contrast: #ffffff;
  --color-success: #157a3d;
  --color-success-bg: #e7f6ec;
  --color-error: #b3261e;
  --color-error-bg: #fdecea;
  --color-warning: #8a5a00;
  --color-warning-bg: #fff6e0;
  --color-code-bg: #0f1620;
  --color-code-text: #d7e3f4;
  --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.06);
  --shadow-md: 0 2px 8px rgba(16, 24, 40, 0.08);
}

:root[data-theme="dark"] {
  --color-bg: #0d1117;
  --color-surface: #151b23;
  --color-surface-alt: #1c232d;
  --color-border: #2a323d;
  --color-text: #e6edf3;
  --color-text-muted: #9aa5b1;
  --color-primary: #4c9be8;
  --color-primary-hover: #6fb0ee;
  --color-primary-contrast: #06111d;
  --color-success: #4fbd7a;
  --color-success-bg: #10271a;
  --color-error: #f0776d;
  --color-error-bg: #2a1414;
  --color-warning: #e0b34d;
  --color-warning-bg: #2a2210;
  --color-code-bg: #05090e;
  --color-code-text: #c9d8ec;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 2px 10px rgba(0, 0, 0, 0.5);
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}

* { box-sizing: border-box; }
html { scroll-padding-top: 80px; }
body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
code, pre, .mono { font-family: var(--font-mono); }

.skip-link {
  position: absolute; left: -9999px; top: 0; background: var(--color-primary);
  color: var(--color-primary-contrast); padding: 10px 16px; z-index: 1000; border-radius: 0 0 6px 0;
}
.skip-link:focus { left: 0; }

/* ---------- Header ---------- */
.site-header {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  position: sticky; top: 0; z-index: 100;
}
.site-header__inner {
  max-width: var(--max-width); margin: 0 auto; padding: 14px 20px;
  display: flex; align-items: center; gap: 24px; justify-content: space-between;
}
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: 1.05rem; color: var(--color-text); }
.brand__mark {
  width: 28px; height: 28px; border-radius: 6px; background: var(--color-primary);
  color: var(--color-primary-contrast); display: flex; align-items: center; justify-content: center;
  font-family: var(--font-mono); font-weight: 700; font-size: 0.85rem;
}
.brand:hover { text-decoration: none; }
.main-nav { display: flex; gap: 4px; align-items: center; flex-wrap: wrap; }
.main-nav a {
  color: var(--color-text-muted); padding: 8px 12px; border-radius: var(--radius-sm); font-size: 0.92rem; font-weight: 500;
}
.main-nav a:hover, .main-nav a[aria-current="page"] { background: var(--color-surface-alt); color: var(--color-text); text-decoration: none; }
.header-actions { display: flex; align-items: center; gap: 8px; }

.theme-toggle {
  border: 1px solid var(--color-border); background: var(--color-surface); color: var(--color-text);
  border-radius: var(--radius-sm); padding: 7px 10px; cursor: pointer; font-size: 0.85rem; display: flex; gap: 6px; align-items: center;
}
.theme-toggle:hover { background: var(--color-surface-alt); }

/* ---------- Layout ---------- */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }
main { padding: 32px 0 64px; }
.breadcrumb { font-size: 0.85rem; color: var(--color-text-muted); margin-bottom: 16px; }
.breadcrumb a { color: var(--color-text-muted); }
.breadcrumb a:hover { color: var(--color-primary); }

h1 { font-size: 1.9rem; margin: 0 0 6px; letter-spacing: -0.01em; }
h2 { font-size: 1.3rem; margin: 32px 0 12px; }
h3 { font-size: 1.05rem; margin: 20px 0 8px; }
.lede { color: var(--color-text-muted); font-size: 1.02rem; max-width: 70ch; margin: 0 0 24px; }

/* ---------- Cards ---------- */
.card {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 24px; margin-bottom: 24px; box-shadow: var(--shadow-sm);
}
.card > h2:first-child, .card > h3:first-child { margin-top: 0; }

/* ---------- Forms ---------- */
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 0.88rem; font-weight: 600; margin-bottom: 6px; }
.field .hint { font-size: 0.8rem; color: var(--color-text-muted); margin-top: 4px; }
input[type="text"], input[type="number"], input[type="url"], select, textarea {
  width: 100%; padding: 10px 12px; border: 1px solid var(--color-border); border-radius: var(--radius-sm);
  background: var(--color-bg); color: var(--color-text); font-size: 0.95rem; font-family: var(--font-mono);
}
select { font-family: var(--font-sans); }
input:focus, select:focus, textarea:focus, button:focus, a:focus {
  outline: 3px solid var(--color-primary); outline-offset: 1px;
}
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 640px) { .field-row { grid-template-columns: 1fr; } }
.unit-row { display: grid; grid-template-columns: 2fr 1fr; gap: 8px; }

.btn {
  display: inline-flex; align-items: center; gap: 6px; border: 1px solid transparent; border-radius: var(--radius-sm);
  padding: 10px 18px; font-size: 0.92rem; font-weight: 600; cursor: pointer; font-family: var(--font-sans);
}
.btn-primary { background: var(--color-primary); color: var(--color-primary-contrast); }
.btn-primary:hover { background: var(--color-primary-hover); }
.btn-secondary { background: var(--color-surface); border-color: var(--color-border); color: var(--color-text); }
.btn-secondary:hover { background: var(--color-surface-alt); }
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 4px; }

/* ---------- Results ---------- */
.results { display: none; }
.results.is-visible { display: block; }
.result-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; margin: 16px 0; }
.result-item { background: var(--color-surface-alt); border-radius: var(--radius-sm); padding: 12px 14px; border: 1px solid var(--color-border); }
.result-item .label { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.04em; color: var(--color-text-muted); margin-bottom: 4px; }
.result-item .value { font-family: var(--font-mono); font-size: 1rem; word-break: break-word; }

table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
th, td { text-align: left; padding: 9px 10px; border-bottom: 1px solid var(--color-border); }
th { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.03em; color: var(--color-text-muted); }
.table-scroll { overflow-x: auto; }

.alert { border-radius: var(--radius-sm); padding: 12px 14px; font-size: 0.9rem; margin: 12px 0; border: 1px solid; }
.alert-error { background: var(--color-error-bg); color: var(--color-error); border-color: var(--color-error); }
.alert-success { background: var(--color-success-bg); color: var(--color-success); border-color: var(--color-success); }
.alert-warning { background: var(--color-warning-bg); color: var(--color-warning); border-color: var(--color-warning); }
.alert-info { background: var(--color-surface-alt); color: var(--color-text-muted); border-color: var(--color-border); }
[role="status"] { min-height: 1.2em; }

.badge {
  display: inline-block; font-size: 0.72rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.03em;
  padding: 3px 8px; border-radius: 999px; background: var(--color-surface-alt); color: var(--color-text-muted); border: 1px solid var(--color-border);
}
.copy-btn { position: relative; }
.copy-btn[data-copied="true"]::after {
  content: "Copied!"; position: absolute; top: -28px; left: 0; background: var(--color-success); color: #fff;
  font-size: 0.75rem; padding: 3px 8px; border-radius: 4px;
}

/* ---------- Homepage ---------- */
.hero { text-align: center; padding: 56px 0 40px; }
.hero h1 { font-size: 2.4rem; }
.hero .lede { margin: 0 auto 28px; }
.search-box { max-width: 520px; margin: 0 auto 8px; position: relative; }
.search-box input {
  width: 100%; padding: 13px 16px; font-family: var(--font-sans); font-size: 1rem;
  border-radius: 999px; border: 1px solid var(--color-border);
}

/* ---------- Tool grid / directory ---------- */
.tool-category { margin-bottom: 36px; }
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.tool-card {
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 18px; display: flex; flex-direction: column; gap: 6px; box-shadow: var(--shadow-sm);
}
.tool-card__icon { font-size: 1.4rem; }
.tool-card h3 { margin: 4px 0 0; font-size: 1.02rem; }
.tool-card p { margin: 0; color: var(--color-text-muted); font-size: 0.88rem; flex-grow: 1; }
.tool-card .btn { align-self: flex-start; margin-top: 8px; }
.tool-card[hidden] { display: none; }

.related-tools { display: flex; flex-wrap: wrap; gap: 8px; }
.related-tools a {
  border: 1px solid var(--color-border); border-radius: 999px; padding: 6px 14px; font-size: 0.85rem; color: var(--color-text);
}
.related-tools a:hover { background: var(--color-surface-alt); text-decoration: none; }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--color-border); background: var(--color-surface); margin-top: 40px; }
.site-footer__inner {
  max-width: var(--max-width); margin: 0 auto; padding: 28px 20px; display: flex; justify-content: space-between;
  flex-wrap: wrap; gap: 16px; color: var(--color-text-muted); font-size: 0.85rem;
}
.footer-links { display: flex; gap: 16px; flex-wrap: wrap; }
.footer-links a { color: var(--color-text-muted); }

.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

::selection { background: var(--color-primary); color: var(--color-primary-contrast); }