/**
 * Shared dark UI for classroom tools — palette and rhythm aligned with landing.html.
 */
*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  --edu-gray: #d9d9d9;
  --edu-teal: #3c6e71;
  --edu-teal-light: #4a8a8d;
  --edu-charcoal: #353535;
  --edu-white: #ffffff;

  --bg-1: #141414;
  --bg-2: #1a1f1f;
  --surface: rgba(45, 52, 52, 0.78);
  --surface-strong: rgba(53, 57, 57, 0.9);
  --surface-border: rgba(217, 217, 217, 0.12);
  --surface-border-strong: rgba(60, 110, 113, 0.42);
  --text: #f0f0f0;
  --muted: #a0a8a8;
  --accent: #5c9ea1;
  --accent-soft: rgba(60, 110, 113, 0.22);
  --danger: #d97878;
  --green: #6eb3a8;
  --yellow: #d4b876;
  --red: #c97a7a;
  --shadow-lg: 0 28px 80px rgba(0, 0, 0, 0.48);
  --shadow-md: 0 14px 36px rgba(0, 0, 0, 0.32);
}

html,
body {
  height: 100%;
  margin: 0;
}

body {
  font-family: "Montserrat", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-weight: 300;
  color: var(--text);
  background-color: var(--edu-charcoal);
  background-image:
    linear-gradient(to right, rgba(217, 217, 217, 0.055) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(217, 217, 217, 0.055) 1px, transparent 1px),
    radial-gradient(circle at 50% 58%, rgba(60, 110, 113, 0.2) 0%, rgba(60, 110, 113, 0.06) 42%, transparent 72%);
  background-size: 40px 40px, 40px 40px, 100% 100%;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}