:root{
    --bg:#f8f9fa;
    --nav:#343a40;
    --nav-2:#2b3a4a;
    --accent:#0d6efd;
    --accent-2:#7c4dff;
    --text:#212529;
}

html{
    scroll-behavior:smooth;
}

body{
    margin:0;
    font-family:system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
    color:var(--text);
    background:linear-gradient(180deg,var(--bg), #eef3f8 80%);
}

/* =========================
   Barra de navegación
========================= */
.navbar{
    position:fixed;
    top:0;
    left:0;
    right:0;
    height:64px;
    background:linear-gradient(90deg,var(--nav), var(--nav-2));
    color:#fff;
    display:flex;
    align-items:center;
    justify-content:space-between;
    padding:0 16px;
    box-shadow:0 2px 10px rgba(11,22,35,0.18);
    z-index:1000;
}

.brand{
    font-weight:700;
    font-size:1.05rem;
    letter-spacing:0.2px;
    color:var(--accent);
}

.nav-links{
    display:flex;
    gap:12px;
    align-items:center;
}

.nav-links a{
    color:#ddd;
    text-decoration:none;
    padding:8px 10px;
    border-radius:6px;
    transition:background .15s, color .15s, transform .12s;
    font-size:0.95rem;
}

.nav-links a:hover,
.nav-links a:focus{
    background:rgba(255,255,255,0.06);
    color:#fff;
    transform:translateY(-1px);
}

.nav-links a.active{
    color:#fff;
    background:linear-gradient(
            90deg,
            rgba(13,110,253,0.12),
            rgba(124,77,255,0.06)
    );
    box-shadow:inset 0 -3px 0 var(--accent);
}

/* =========================
   Contenido principal
========================= */
main{
    padding-top:104px; /* espacio por navbar fija */
    max-width:1000px;
    margin:0 auto;
    padding-left:16px;
    padding-right:16px;
}

/* =========================
   Secciones
========================= */
section{
    background:#fff;
    border-radius:8px;
    padding:24px;
    margin-bottom:20px;
    box-shadow:0 1px 3px rgba(0,0,0,0.06);
}

h1, h2{
    margin:0 0 12px 0;
    color:var(--accent);
}

p{
    margin:0 0 12px 0;
    line-height:1.5;
    color:#333;
}

ul, ol{
    margin-left:20px;
}

/* =========================
   Footer
========================= */
footer{
    text-align:center;
    padding:15px;
    color:white;
    margin-top:202px;
}

/* =========================
   Responsive
========================= */
@media (max-width:900px){
    main{
        max-width:95%;
    }
}