html, body {
font: 15px/1.6 "Helvetica Neue", Helvetica, Arial, sans-serif;
color: #333;
/* mathy graph-paper background: fine grid + heavier every 5th line over a light gradient */

body {
font: 15px/1.6 "Helvetica Neue", Helvetica, Arial, sans-serif;
color: #333;
background: #dcdcdc;

/* subtle page gradient, common in early 2010s */

}
a { color: #800000; text-decoration: none; }
a:hover { text-decoration: underline; color: #0b6b3a; }

/* ===== Accessible skip link ===== */
.skip-link { position: absolute; left: -9999px; top: 0; padding: 6px 8px; background: #fff; border: 1px solid #999; border-radius: 3px; }
.skip-link:focus { left: 12px; top: 12px; z-index: 1000; }

/* ===== Header / Top nav (full-width bar, gradient) ===== */


.brand { color: #fff; font-weight: 700; }
.nav a {
color: #eaf2ff;
text-transform: uppercase; font-size: 12px; letter-spacing: .06em;
padding: 8px 10px; border-radius: 3px;
border-left: 1px solid rgba(255,255,255,.15);
}
.nav a:first-child { border-left: none; }
.nav a:hover { background: rgba(255,255,255,.12); }

/* ===== Layout ===== */
.main { padding: 24px 16px 40px; } /* space for fixed header */
.container { width: 720px; margin: 0 auto; }
.sheet {
background: #fff;
border: 2px solid #0b6b3a; border-radius: 4px;
box-shadow: 0 1px 2px rgba(0,0,0,.05);
padding: 0 24px 20px; /* no top padding so the nav sits right under the border */
}

/* ===== Sheet nav (attached to sheet) ===== */
.sheet-nav {
display: flex; align-items: center; justify-content: space-between;
margin: 0 0 12px 0;
padding: 0;
background: transparent;
border: 0;
box-shadow: none;
}
.sheet-nav .brand { color: #800000; font-weight: 700; }
.sheet-nav .links a {
color: #800000;
text-transform: uppercase; font-size: 12px; letter-spacing: .06em;
padding: 6px 8px;
}
.sheet-nav .links a:first-child { }
.sheet-nav .links a:hover { color: #0b6b3a; background: transparent; }

/* ===== Typography ===== */
h1, h2 { font-weight: 600; margin: 0 0 8px; }
h1 { font-size: 28px; line-height: 1.25; }
h2 { font-size: 20px; }
p { margin: 0 0 12px; color: #444; }
.muted { color: #666; }

/* ===== Sections ===== */
section { padding: 14px 0; border-top: 1px solid #eee; }
section:first-of-type { border-top: 0; }

/* ===== Buttons (gradient, small radius, light bevel) ===== */
.btn {
display: inline-block; font-weight: bold; text-decoration: none;
background: linear-gradient(#941a1a, #800000);
color: #fff; border: 1px solid #5c0000; border-radius: 3px;
padding: 8px 12px;
text-shadow: 0 -1px 0 rgba(0,0,0,.2);
box-shadow: inset 0 1px 0 rgba(255,255,255,.25), 0 1px 2px rgba(0,0,0,.1);
}
.btn:hover { filter: brightness(1.05); }

/* ===== Anchor targets for fixed header ===== */
:target { scroll-margin-top: 12px; }

/* ===== Footer ===== */
footer { text-align: center; color: #777; font-size: 13px; margin-top: 8px; }