/* IPG homework pages — Google-style, light, readable on a laptop or phone. */
:root {
  --g-blue: #4285F4; --g-blue-d: #1a5fc4; --g-red: #EA4335; --g-red-d: #c0271a;
  --g-yellow: #FBBC04; --g-yellow-d: #b8860b; --g-green: #34A853; --g-green-d: #1e7e34;
  --bg: #f1f6ef; --surface: #ffffff; --border: #dadce0; --border-strong: #c4c9cf;
  --text: #1a1f2e; --text-dim: #4a5066; --text-muted: #6b7184;
  --font-display: 'Roboto', 'Plus Jakarta Sans', sans-serif;
  --mono: 'JetBrains Mono', Menlo, monospace;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--text); font: 15px/1.55 'Plus Jakarta Sans', system-ui, sans-serif; }
a { color: var(--g-blue-d); }

.hw-top { position: sticky; top: 0; z-index: 10; background: #fff; border-bottom: 1px solid #e3e7e2; }
.hw-top-in { max-width: 1060px; margin: 0 auto; padding: 10px 20px; display: flex; align-items: center; gap: 14px; }
.hw-top img { height: 30px; width: auto; display: block; }
.hw-top .sep { width: 1px; height: 28px; background: #d7dbd5; }
.hw-brand { font: 700 15px var(--font-display); }
.hw-brand em { font-style: normal; color: var(--g-red); }
.hw-nav { margin-left: auto; display: flex; gap: 6px; flex-wrap: wrap; }
.hw-nav a { text-decoration: none; font: 600 12.5px var(--font-display); padding: 6px 12px; border-radius: 999px; border: 1px solid var(--border); color: var(--text-dim); background: #fff; }
.hw-nav a.on { background: var(--g-blue); border-color: var(--g-blue); color: #fff; }

.hw-hero { max-width: 1060px; margin: 0 auto; padding: 34px 20px 8px; }
.hw-kicker { font: 600 12px var(--mono); letter-spacing: 1.2px; color: var(--g-red); text-transform: uppercase; }
.hw-hero h1 { font: 800 40px/1.08 var(--font-display); margin: 8px 0 10px; letter-spacing: -.5px; }
.hw-hero p { margin: 0; max-width: 760px; color: var(--text-dim); font-size: 16px; }
.hw-facts { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.hw-facts span { background: #fff; border: 1px solid #e3e7e2; border-radius: 999px; padding: 6px 12px; font-size: 13px; }
.hw-facts b { color: var(--text); }
.hw-lesson { margin-top: 16px; background: #fff; border-left: 4px solid var(--g-yellow); border-radius: 12px; padding: 12px 16px; box-shadow: 0 1px 2px rgba(60,64,67,.15); }
.hw-toc { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 14px; }
.hw-toc a { font: 600 12.5px var(--font-display); text-decoration: none; padding: 5px 11px; border-radius: 8px; background: #e8efe6; color: var(--text-dim); }

main#hw-main { max-width: 1060px; margin: 0 auto; padding: 0 20px 40px; }
.hw-sec { margin-top: 28px; background: #fff; border-radius: 16px; padding: 22px 22px 24px; box-shadow: 0 1px 2px rgba(60,64,67,.18), 0 1px 3px 1px rgba(60,64,67,.08); scroll-margin-top: 70px; }
.hw-eyebrow { font: 600 11.5px var(--mono); letter-spacing: 1px; text-transform: uppercase; color: var(--g-red); }
.hw-sec h2 { font: 800 26px/1.15 var(--font-display); margin: 4px 0 6px; }
.hw-intro { margin: 0 0 14px; color: var(--text-dim); font-size: 14px; }
.hw-sec .reveal { opacity: 1 !important; transform: none !important; }

.hw-steps { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 12px; }
.hw-step { display: flex; gap: 14px; padding: 14px 16px; border: 1px solid #e8eaed; border-left: 4px solid var(--c); border-radius: 12px; }
.hw-num { flex: 0 0 auto; width: 32px; height: 32px; border-radius: 50%; display: grid; place-items: center; background: var(--c); color: #fff; font: 700 15px var(--font-display); }
.hw-body { flex: 1; min-width: 0; }
.hw-body h3 { margin: 4px 0 4px; font: 700 16px var(--font-display); }
.hw-body p { margin: 0 0 8px; font-size: 14px; color: var(--text-dim); }
.hw-body code { font: 600 13px var(--mono); background: #f1f3f4; padding: 1px 5px; border-radius: 4px; }
.hw-prompt { position: relative; background: #f8f9fa; border: 1px solid #e3e5e8; border-radius: 10px; padding: 10px 12px 40px; margin: 6px 0 8px; }
.hw-prompt pre { margin: 0; white-space: pre-wrap; font: 13px/1.55 var(--mono); color: #202124; }
.hw-copy { position: absolute; right: 10px; bottom: 8px; border: 0; background: var(--g-blue); color: #fff; font: 600 12.5px var(--font-display); border-radius: 999px; padding: 6px 14px; cursor: pointer; }
.hw-open { display: inline-block; text-decoration: none; font: 600 13px var(--font-display); color: #fff; background: var(--g-green); border-radius: 999px; padding: 7px 16px; }

.hw-checks { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.hw-check { display: flex; gap: 10px; align-items: flex-start; padding: 10px 12px; border: 1px solid #e8eaed; border-radius: 10px; cursor: pointer; font-size: 14px; }
.hw-check input { width: 18px; height: 18px; margin: 1px 0 0; accent-color: var(--g-green); }
.hw-progress { margin: 12px 0 0; font: 700 14px var(--font-display); color: var(--g-green-d); }

.hw-stuck { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.hw-tip { border: 1px solid #e8eaed; border-top: 3px solid var(--c); border-radius: 10px; padding: 10px 12px; }
.hw-tip b { display: block; font: 700 14px var(--font-display); margin-bottom: 3px; }
.hw-tip p { margin: 0; font-size: 13.5px; color: var(--text-dim); }

.hw-foot { max-width: 1060px; margin: 0 auto; padding: 10px 20px 40px; display: flex; gap: 10px; flex-wrap: wrap; }
.hw-foot a { text-decoration: none; font: 600 14px var(--font-display); padding: 10px 18px; border-radius: 999px; background: #fff; border: 1px solid var(--border); color: var(--text); }
.hw-foot a.p { background: var(--g-blue); border-color: var(--g-blue); color: #fff; }

@media (max-width: 720px) {
  .hw-hero h1 { font-size: 30px; }
  .hw-checks, .hw-stuck { grid-template-columns: 1fr; }
  .hw-nav { display: none; }
  .hw-sec { padding: 18px 16px; }
}