/* ==========================================================================
   STP MUET — Base Design System
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=IBM+Plex+Sans:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500;600&display=swap');

:root {
  /* ---- Brand ---- */
  --stp-primary: #006635;
  --stp-primary-bright: #12925A;   /* legible brightened primary for dark bg */
  --stp-secondary: #7BBF43;

  /* ---- Surfaces (dark, institutional — not pure black) ---- */
  --bg-0: #071510;               /* page background */
  --bg-1: #0C1E17;               /* section alt background */
  --bg-2: #10261D;               /* elevated card background */
  --bg-3: #163024;               /* hover/elevated-2 */

  /* ---- Text ---- */
  --text-0: #F2F6F1;             /* headings / high emphasis */
  --text-1: #C7D6CB;             /* body */
  --text-2: #8FA598;             /* muted / captions */
  --text-3: #5F7368;             /* faint / disabled */

  /* ---- Lines ---- */
  --line-1: rgba(123, 191, 67, 0.16);
  --line-2: rgba(123, 191, 67, 0.32);
  --line-bright: rgba(123, 191, 67, 0.55);

  /* ---- Feedback ---- */
  --success: #12925A;
  --error: #D96C5B;

  /* ---- Type ---- */
  --font-display: 'Space Grotesk', 'IBM Plex Sans', sans-serif;
  --font-body: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'IBM Plex Mono', 'SFMono-Regular', Consolas, monospace;

  /* ---- Scale ---- */
  --step--1: clamp(0.83rem, 0.8rem + 0.15vw, 0.9rem);
  --step-0:  clamp(1rem, 0.96rem + 0.2vw, 1.08rem);
  --step-1:  clamp(1.2rem, 1.13rem + 0.35vw, 1.4rem);
  --step-2:  clamp(1.5rem, 1.35rem + 0.7vw, 1.9rem);
  --step-3:  clamp(1.9rem, 1.6rem + 1.4vw, 2.6rem);
  --step-4:  clamp(2.4rem, 1.9rem + 2.4vw, 3.6rem);
  --step-5:  clamp(3rem, 2.2rem + 3.8vw, 5rem);

  /* ---- Layout ---- */
  --container: 1240px;
  --gutter: clamp(1.25rem, 4vw, 3rem);
  --radius-s: 4px;
  --radius-m: 8px;
  --radius-l: 14px;

  /* ---- Motion ---- */
  --ease: cubic-bezier(.22,.61,.36,1);
  --dur-fast: 160ms;
  --dur-med: 360ms;
  --dur-slow: 640ms;
}

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

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
html:focus-within { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg-0);
  color: var(--text-1);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  background-image:
    radial-gradient(ellipse 900px 500px at 12% -8%, rgba(0,102,53,0.28), transparent 60%),
    radial-gradient(ellipse 700px 500px at 100% 8%, rgba(123,191,67,0.10), transparent 55%);
  background-repeat: no-repeat;
}

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

a { color: inherit; text-decoration: none; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--text-0);
  line-height: 1.12;
  font-weight: 600;
  margin: 0 0 0.5em;
  letter-spacing: -0.01em;
}
h1 { font-size: var(--step-5); }
h2 { font-size: var(--step-4); }
h3 { font-size: var(--step-2); }
h4 { font-size: var(--step-1); }
p { margin: 0 0 1em; color: var(--text-1); }
p:last-child { margin-bottom: 0; }

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

section { position: relative; }

/* ---- Focus states (accessibility) ---- */
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--stp-secondary);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---- Skip link ---- */
.skip-link {
  position: absolute;
  left: 1rem;
  top: -60px;
  background: var(--stp-secondary);
  color: #06210F;
  font-family: var(--font-body);
  font-weight: 600;
  padding: 0.7rem 1.1rem;
  border-radius: var(--radius-s);
  z-index: 1000;
  transition: top var(--dur-fast) var(--ease);
}
.skip-link:focus { top: 1rem; }

/* ---- Eyebrow / label ---- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6em;
  font-family: var(--font-mono);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--stp-secondary);
  margin-bottom: 1rem;
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--stp-secondary);
  display: inline-block;
}

/* ---- Section heading block ---- */
.section-head {
  max-width: 700px;
  margin-bottom: clamp(2rem, 5vw, 3.5rem);
}
.section-head.center { margin-inline: auto; text-align: center; }
.section-head p { color: var(--text-2); font-size: var(--step-1); }

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.55em;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: var(--step--1);
  letter-spacing: 0.01em;
  padding: 0.85em 1.5em;
  border-radius: var(--radius-s);
  border: 1px solid transparent;
  cursor: pointer;
  transition: background var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease), transform var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
  white-space: nowrap;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: var(--stp-secondary);
  color: #06210F;
}
.btn-primary:hover { background: #8FD35A; }

.btn-outline {
  background: transparent;
  color: var(--text-0);
  border-color: var(--line-2);
}
.btn-outline:hover { border-color: var(--stp-secondary); background: rgba(123,191,67,0.07); }

.btn-ghost {
  background: transparent;
  color: var(--stp-secondary);
  padding-inline: 0;
}
.btn-ghost::after { content: "→"; transition: transform var(--dur-fast) var(--ease); }
.btn-ghost:hover::after { transform: translateX(3px); }

.btn-arrow::after { content: "↗"; font-size: 0.9em; }

/* ---- Cards ---- */
.card {
  background: var(--bg-2);
  border: 1px solid var(--line-1);
  border-radius: var(--radius-m);
  padding: clamp(1.4rem, 2.5vw, 2rem);
  position: relative;
  transition: border-color var(--dur-med) var(--ease), background var(--dur-med) var(--ease), transform var(--dur-med) var(--ease);
}
.card:hover { border-color: var(--line-2); background: var(--bg-3); }

/* corner-bracket motif — engineering/blueprint reference */
.card::before, .card::after {
  content: "";
  position: absolute;
  width: 12px; height: 12px;
  border: 1.5px solid var(--stp-secondary);
  opacity: 0;
  transition: opacity var(--dur-med) var(--ease);
}
.card::before { top: -1px; left: -1px; border-right: none; border-bottom: none; }
.card::after { bottom: -1px; right: -1px; border-left: none; border-top: none; }
.card:hover::before, .card:hover::after { opacity: 1; }

/* ---- Tag / pill ---- */
.tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-2);
  border: 1px solid var(--line-1);
  border-radius: 999px;
  padding: 0.3em 0.8em;
}

/* ---- Divider ---- */
.hr {
  height: 1px;
  background: var(--line-1);
  border: 0;
  margin: 0;
}

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

/* ---- Grid utilities ---- */
.grid { display: grid; gap: clamp(1rem, 2vw, 1.75rem); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 900px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 620px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

/* ---- Reveal-on-scroll (restrained) ---- */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity var(--dur-slow) var(--ease), transform var(--dur-slow) var(--ease);
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; }
}