/* ============================================================
   SheetSense Dark — shared design system
   Used by: index.html, about/index.html, contact.html
   (bracket/ keeps a synced copy of the token block; retro/ is independent)
   ============================================================ */

:root {
  /* Canvas */
  --bg-0: #0A0C10;
  --bg-1: #11141B;
  --bg-2: #181D27;
  --border: #232A36;
  --border-strong: #303948;

  /* Text */
  --text-1: #E8EBF1;
  --text-2: #9AA3B5;
  --text-3: #5E6878;

  /* Accent */
  --accent: #3DE8C6;
  --accent-hover: #7CF2DC;
  --accent-dim: rgba(61, 232, 198, 0.10);
  --accent-border: rgba(61, 232, 198, 0.35);

  /* Reserved */
  --gold: #E5B53C;
  --danger: #F0645C;

  /* Shape */
  --r-sm: 6px;
  --r-md: 10px;

  /* Type */
  --font-display: 'Space Grotesk', 'Inter', -apple-system, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, monospace;

  /* Motion */
  --t-fast: 120ms cubic-bezier(0.25, 0.1, 0.25, 1);
  --t-med: 240ms cubic-bezier(0.22, 1, 0.36, 1);
}

/* ---------- Reset / base ---------- */

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg-0);
  color: var(--text-2);
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

h1, h2, h3 {
  font-family: var(--font-display);
  color: var(--text-1);
  line-height: 1.25;
  font-weight: 700;
}

h1 { font-size: 40px; line-height: 1.1; }
h2 { font-size: 28px; }
h3 { font-size: 20px; }
h4 { color: var(--text-1); font-size: 16px; font-weight: 600; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

::selection { background: var(--accent-dim); color: var(--text-1); }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}

/* ---------- Mono utilities ---------- */

.mono-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
}

.section-index {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 12px;
}

/* ---------- Nav ---------- */

nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
  height: 60px;
  background: rgba(10, 12, 16, 0.92);
  border-bottom: 1px solid var(--border);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-1);
}
.nav-logo:hover { color: var(--text-1); }
.nav-logo img { width: 28px; height: 28px; }
.nav-logo span {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.06em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}
.nav-links a {
  display: block;
  padding: 8px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-2);
  border-radius: var(--r-sm);
  transition: color var(--t-fast), background var(--t-fast);
}
.nav-links a:hover { color: var(--text-1); background: var(--bg-2); }
.nav-links a.active {
  color: var(--text-1);
  box-shadow: inset 0 -2px 0 var(--accent);
  border-radius: 0;
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
}
.hamburger span {
  width: 22px;
  height: 2px;
  background: var(--text-1);
  transition: transform var(--t-med), opacity var(--t-fast);
}
.hamburger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

@media (max-width: 768px) {
  .hamburger { display: flex; }
  .nav-links {
    position: fixed;
    top: 60px; left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--bg-0);
    border-bottom: 1px solid var(--border);
    padding: 8px 16px 16px;
    display: none;
  }
  .nav-links.active { display: flex; }
  .nav-links a { padding: 12px 14px; }
  .nav-links a.active { box-shadow: inset 2px 0 0 var(--accent); }
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 22px;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 600;
  color: var(--bg-0);
  background: var(--accent);
  border: 1px solid var(--accent);
  border-radius: var(--r-sm);
  cursor: pointer;
  transition: background var(--t-fast), border-color var(--t-fast);
}
.btn:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: var(--bg-0); }

.btn-ghost {
  background: transparent;
  color: var(--text-1);
  border: 1px solid var(--border-strong);
}
.btn-ghost:hover { background: var(--bg-2); border-color: var(--accent-border); color: var(--text-1); }

/* ---------- Cards ---------- */

.card {
  background: var(--bg-1);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  padding: 24px;
  transition: border-color var(--t-fast), background var(--t-fast);
}
.card:hover { border-color: var(--accent-border); }

/* ---------- Stats ---------- */

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
}

.stat-card {
  background: var(--bg-1);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  padding: 24px;
  text-align: center;
}

.stat-number {
  font-family: var(--font-mono);
  font-size: 40px;
  font-weight: 600;
  color: var(--accent);
  line-height: 1.1;
}
.stat-number .stat-suffix { color: var(--text-3); font-size: 28px; }

.stat-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-top: 8px;
}

/* ---------- Forms ---------- */

.form-row { display: flex; gap: 16px; }
.form-group { margin-bottom: 16px; flex: 1; }
.form-group.half { flex: 1; }

.form-group label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 8px;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 11px 14px;
  font-family: var(--font-body);
  font-size: 16px; /* >=16px so iOS Safari doesn't zoom on focus */
  color: var(--text-1);
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  transition: border-color var(--t-fast);
}
.form-group input::placeholder,
.form-group textarea::placeholder { color: var(--text-3); }
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.form-group select { appearance: none; }
.form-group textarea { min-height: 130px; resize: vertical; }

.response-note {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-top: 16px;
  text-align: center;
}

@media (max-width: 600px) {
  .form-row { flex-direction: column; gap: 0; }
}

/* ---------- Footer ---------- */

footer {
  border-top: 1px solid var(--border);
  padding: 32px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-3);
}
footer a {
  color: var(--text-2);
  display: inline-block;
  padding: 8px 4px;
  margin: -4px 0;
}
footer a:hover { color: var(--accent); }

/* ---------- Layout helpers ---------- */

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 32px;
}

@media (max-width: 600px) {
  .container { padding: 0 20px; }
  h1 { font-size: 32px; }
  h2 { font-size: 24px; }
}