/* =============================================================================
   ON Energy — IP Internal Tooling
   Brand Theme Stylesheet
   -----------------------------------------------------------------------------
   Consumed by index.html and every tool page in this repository. Link via:
     <link rel="stylesheet" href="/assets/css/on-energy-theme.css">

   Palette, typography, and scale are derived from the ON Energy brand
   guidelines. Dark mode is the default; light mode activates via
   prefers-color-scheme: light.
   ============================================================================= */

:root {
  /* -------------------------------------------------------------------
     Primary palette
     ------------------------------------------------------------------- */
  --on-black:         #080808;
  --on-off-white:     #EEEEEE;
  --on-silver:        #AFAFAF;
  --on-harvest-bolt:  #C0B400;
  --on-golden-volt:   #FFF313;

  /* -------------------------------------------------------------------
     Secondary grey scale
     ------------------------------------------------------------------- */
  --on-deep-dark-grey: #202020;
  --on-dark-charcoal:  #282828;
  --on-graphite:       #383838;
  --on-charcoal:       #484848;
  --on-slate:          #585858;
  --on-steel:          #686868;
  --on-mid-grey:       #7D7D7D;
  --on-stone-grey:     #888888;
  --on-cloud-grey:     #989898;
  --on-pale-grey:      #B8B8B8;
  --on-light-grey:     #C8C8C8;
  --on-mist-grey:      #D8D8D8;
  --on-aluminium:      #E8E8E8;

  /* -------------------------------------------------------------------
     Typography
     ------------------------------------------------------------------- */
  --font-sans: "Univers Next", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "Monument Grotesk Mono", "SF Mono", Monaco, Consolas, monospace;

  /* Type scale — Body : H3 : H2 : H1 = 1 : 2 : 3 : 4 */
  --fs-body:  16px;
  --fs-h3:    32px;
  --fs-h2:    48px;
  --fs-h1:    64px;
  --fs-mono:  12px;
  --fs-lead:  18px;

  --lh-tight: 1.1;
  --lh-body:  1.6;

  --tracking-heading:  -0.04em;
  --tracking-body:     -0.02em;
  --tracking-mono:     0.05em;
  --tracking-mono-tight: 0.02em;

  /* -------------------------------------------------------------------
     Semantic tokens — dark mode (default)
     ------------------------------------------------------------------- */
  --color-bg:              var(--on-black);
  --color-surface:         var(--on-deep-dark-grey);
  --color-surface-raised:  var(--on-dark-charcoal);
  --color-border:          var(--on-graphite);
  --color-border-strong:   var(--on-charcoal);
  --color-text:            var(--on-off-white);
  --color-text-muted:      var(--on-pale-grey);
  --color-text-subtle:     var(--on-mid-grey);
  --color-accent:          var(--on-golden-volt);
  --color-accent-hover:    var(--on-harvest-bolt);
  --color-accent-muted:    var(--on-harvest-bolt);

  /* -------------------------------------------------------------------
     Layout
     ------------------------------------------------------------------- */
  --container-max: 1120px;
  --container-pad: 32px;
  --radius:        2px;
  --hairline:      1px;

  --dur-fast: 150ms;
  --dur-med:  200ms;
  --ease:     cubic-bezier(0.2, 0.0, 0.2, 1);
}

@media (prefers-color-scheme: light) {
  :root {
    --color-bg:             var(--on-off-white);
    --color-surface:        #FFFFFF;
    --color-surface-raised: var(--on-aluminium);
    --color-border:         var(--on-mist-grey);
    --color-border-strong:  var(--on-light-grey);
    --color-text:           var(--on-black);
    --color-text-muted:     var(--on-slate);
    --color-text-subtle:    var(--on-steel);
    --color-accent:         var(--on-harvest-bolt);
    --color-accent-hover:   var(--on-black);
    --color-accent-muted:   var(--on-harvest-bolt);
  }
}

/* =============================================================================
   Reset & base
   ============================================================================= */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: 400;
  line-height: var(--lh-body);
  letter-spacing: var(--tracking-body);
  color: var(--color-text);
  background: var(--color-bg);
  text-align: left;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
}

img,
svg {
  max-width: 100%;
  display: block;
}

::selection {
  background: var(--on-harvest-bolt);
  color: var(--on-black);
}

/* =============================================================================
   Typography
   ============================================================================= */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 300;
  line-height: var(--lh-tight);
  letter-spacing: var(--tracking-heading);
  color: var(--color-text);
}

h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }
h4 { font-size: 24px; }
h5 { font-size: 20px; }
h6 { font-size: var(--fs-body); }

p {
  letter-spacing: var(--tracking-body);
  color: var(--color-text-muted);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease);
}

a:hover,
a:focus-visible {
  color: var(--color-accent-hover);
}

a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: var(--radius);
}

/* Technical metadata / labels — always monospace, always uppercase */
.mono,
.eyebrow,
.meta,
.label {
  font-family: var(--font-mono);
  font-size: var(--fs-mono);
  font-weight: 400;
  letter-spacing: var(--tracking-mono);
  text-transform: uppercase;
  color: var(--color-text-subtle);
}

/* =============================================================================
   Layout primitives
   ============================================================================= */

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 72px var(--container-pad) 120px;
}

.rule {
  height: var(--hairline);
  background: var(--color-border);
  border: 0;
  margin: 48px 0;
}

/* =============================================================================
   Site header
   ============================================================================= */

.site-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 24px;
  padding-bottom: 20px;
  margin-bottom: 72px;
  border-bottom: var(--hairline) solid var(--color-border);
}

.site-header .brand {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text);
}

.site-header .brand .sep {
  color: var(--color-accent);
  margin: 0 4px;
}

.site-header .status {
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: var(--tracking-mono);
  color: var(--color-text-subtle);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.site-header .status::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(192, 180, 0, 0.15);
}

/* =============================================================================
   Hero
   ============================================================================= */

.hero {
  margin-bottom: 96px;
}

.hero .eyebrow {
  display: inline-block;
  color: var(--color-accent);
  margin-bottom: 24px;
  letter-spacing: 0.08em;
}

.hero h1 {
  max-width: 20ch;
  margin-bottom: 28px;
}

.hero .lead {
  max-width: 62ch;
  font-size: var(--fs-lead);
  line-height: 1.55;
  color: var(--color-text-muted);
}

/* =============================================================================
   Section header
   ============================================================================= */

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 20px;
  margin-bottom: 36px;
  border-bottom: var(--hairline) solid var(--color-border);
}

.section-header h2 {
  font-size: var(--fs-h3);
}

.section-header .count {
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: var(--tracking-mono);
  color: var(--color-text-subtle);
}

/* =============================================================================
   Tool grid + cards
   ============================================================================= */

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 20px;
}

.tool-card {
  display: flex;
  flex-direction: column;
  min-height: 260px;
  padding: 32px;
  background: var(--color-surface);
  border: var(--hairline) solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  position: relative;
  overflow: hidden;
  transition:
    border-color var(--dur-med) var(--ease),
    background-color var(--dur-med) var(--ease),
    transform var(--dur-med) var(--ease);
}

.tool-card::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 2px;
  background: var(--color-accent);
  opacity: 0;
  transition: opacity var(--dur-med) var(--ease);
}

.tool-card:hover,
.tool-card:focus-visible {
  border-color: var(--color-border-strong);
  background: var(--color-surface-raised);
  transform: translateY(-1px);
}

.tool-card:hover::before,
.tool-card:focus-visible::before {
  opacity: 1;
}

.tool-card .tool-meta {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 28px;
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: var(--tracking-mono);
  color: var(--color-text-subtle);
}

.tool-card .tool-category {
  color: var(--color-accent);
}

.tool-card h3 {
  font-size: 24px;
  font-weight: 300;
  letter-spacing: var(--tracking-heading);
  line-height: 1.15;
  margin-bottom: 12px;
  color: var(--color-text);
}

.tool-card p {
  font-size: 15px;
  line-height: 1.55;
  color: var(--color-text-muted);
  flex-grow: 1;
  margin-bottom: 28px;
  max-width: 42ch;
}

.tool-card .tool-link {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
}

.tool-card .tool-link::after {
  content: "→";
  display: inline-block;
  transition: transform var(--dur-med) var(--ease);
}

.tool-card:hover .tool-link::after,
.tool-card:focus-visible .tool-link::after {
  transform: translateX(6px);
}

/* =============================================================================
   Footer
   ============================================================================= */

.site-footer {
  margin-top: 120px;
  padding-top: 24px;
  border-top: var(--hairline) solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 24px;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: var(--tracking-mono);
  color: var(--color-text-subtle);
}

.site-footer .notice {
  color: var(--color-text-subtle);
}

/* =============================================================================
   Utilities
   ============================================================================= */

.accent-text    { color: var(--color-accent); }
.muted          { color: var(--color-text-muted); }
.subtle         { color: var(--color-text-subtle); }
.text-mono      { font-family: var(--font-mono); }
.uppercase      { text-transform: uppercase; letter-spacing: var(--tracking-mono); }
.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0);
  white-space: nowrap; border: 0;
}

/* =============================================================================
   Responsive
   ============================================================================= */

@media (max-width: 900px) {
  :root {
    --fs-h1: 52px;
    --fs-h2: 40px;
    --fs-h3: 28px;
  }
  .container { padding: 56px 24px 96px; }
  .site-header { margin-bottom: 56px; }
  .hero        { margin-bottom: 72px; }
}

@media (max-width: 640px) {
  :root {
    --fs-h1: 40px;
    --fs-h2: 32px;
    --fs-h3: 22px;
    --fs-lead: 16px;
  }
  .container { padding: 40px 20px 72px; }
  .site-header,
  .site-footer,
  .section-header {
    flex-direction: column;
    align-items: flex-start;
  }
  .tool-grid { gap: 16px; }
  .tool-card { padding: 24px; min-height: 220px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}