:root{--bg-gradient-onyx: linear-gradient(to bottom right, hsl(240, 1%, 25%) 3%, hsl(0, 0%, 19%) 97%);--bg-gradient-jet: linear-gradient(to bottom right, hsla(240, 1%, 18%, 0.251) 0%, hsla(240, 2%, 11%, 0) 100%), hsl(240, 2%, 13%);--border-gradient-onyx: linear-gradient(to bottom right, hsl(0, 0%, 25%) 0%, hsla(0, 0%, 25%, 0) 50%);--text-gradient-yellow: linear-gradient(to right, hsl(45, 100%, 72%), hsl(35, 100%, 68%));--jet: hsl(0, 0%, 22%);--onyx: hsl(240, 1%, 17%);--eerie-black-1: hsl(240, 2%, 13%);--smoky-black: hsl(0, 0%, 7%);--white-2: hsl(0,0%,98%);--orange-yellow-crayola: hsl(45,100%,72%);--vegas-gold: hsl(45,54%,58%);--ff-poppins: 'Poppins', sans-serif;--fs-1: 26px;--fs-2: 20px;--fs-3: 17px;--fs-4: 16px;--radius-12:12px;--radius-20:20px;--shadow-1: -4px 8px 24px hsla(0,0%,0%,0.25);}*{box-sizing:border-box}body{margin:0;background:var(--smoky-black);color:var(--white-2);font-family:var(--ff-poppins);line-height:1.7}.container{max-width:1000px;margin:32px auto;padding:20px}.card{background:var(--border-gradient-onyx);border-radius:var(--radius-20);padding:2px;box-shadow:var(--shadow-1)}.card-inner{background:var(--bg-gradient-jet);border-radius:inherit;padding:20px}.title{background:var(--text-gradient-yellow);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;font-size:var(--fs-1);margin:0 0 8px}.subtitle{color:#cfcfcf;font-size:var(--fs-4);margin:0 0 16px}.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:16px}.btn{color:var(--orange-yellow-crayola);border:1px solid var(--orange-yellow-crayola);padding:8px 14px;border-radius:10px;text-decoration:none;transition:transform .2s ease, box-shadow .2s ease}.btn:hover{background:var(--orange-yellow-crayola);color:#111;transform:translateY(-1px);box-shadow:0 8px 24px rgba(0,0,0,.25)}.back{display:inline-block;margin-top:20px}.topic-icon{width:44px;height:44px;border-radius:10px;background:#fff;padding:8px;object-fit:contain;margin-right:10px;vertical-align:middle}

/* Attractive section cards */
.section-card{background:var(--border-gradient-onyx);border-radius:var(--radius-20);padding:2px;margin:16px 0;box-shadow:var(--shadow-1)}
.section-card>.inner{background:var(--bg-gradient-jet);border-radius:inherit;padding:16px}

/* Gradient underlined headlines */
.headline{font-size:var(--fs-2);font-weight:600;margin:0 0 10px;position:relative;display:inline-block}
.headline::after{content:"";position:absolute;left:0;bottom:-4px;width:100%;height:3px;background:var(--text-gradient-yellow);border-radius:999px;opacity:.8}

/* Check lists */
.list-check{list-style:none;padding:0;margin:0}
.list-check li{position:relative;padding-left:28px;margin:6px 0}
.list-check li::before{content:"✓";position:absolute;left:0;top:0;color:#111;background:var(--text-gradient-yellow);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;font-weight:700}

/* Zebra tables */
table.zebra{width:100%;border-collapse:collapse}
table.zebra th,table.zebra td{border:1px solid rgba(255,255,255,0.08);padding:8px 10px;vertical-align:top}
table.zebra th{background:rgba(255,183,77,0.08);text-align:left}
table.zebra tbody tr:nth-child(odd){background:rgba(255,255,255,0.02)}

/* Small helper */
.muted{color:#bdbdbd;font-size:12px}

/* Shared meta/kicker and two-column grid */
.kicker{letter-spacing:.08em;text-transform:uppercase;color:#ffdd9b;font-weight:600;font-size:12px;margin-bottom:6px}
.meta{color:#cfcfcf;font-size:14px;margin:6px 0 16px}
.two-col{display:grid;grid-template-columns:1fr;gap:14px}
@media(min-width:980px){.two-col{grid-template-columns:1.05fr .95fr}}

/* Zoomable diagrams - consistent sizing */
.diagram-card{background:var(--border-gradient-onyx);border-radius:var(--radius-20);padding:2px;box-shadow:var(--shadow-1)}
.diagram-card .zoom-toolbar{display:flex;gap:8px;align-items:center;justify-content:flex-end;margin:8px}
.diagram-card .btn{padding:6px 10px}
.zoom-wrap{position:relative;border-radius:12px;border:1px solid rgba(255,255,255,0.06);overflow:auto;background:rgba(255,255,255,0.02);height:clamp(260px,55vh,800px)!important;display:flex;align-items:flex-start;justify-content:center}
.zoom-stage{display:inline-block;width:max-content;transform-origin:top center;transform:scale(var(--z,1));transition:transform .15s ease}
.zoom-indicator{color:#bdbdbd;font-size:12px;margin-left:auto}
.diagram-img{display:block;max-width:none;height:auto;border-radius:8px}

/* YouTube thumbnail style */
.yt-thumb{position:relative;border-radius:12px;overflow:hidden;border:1px solid rgba(255,255,255,0.06);background:#0b0b0b;display:block;margin-top:12px}
.yt-thumb img{display:block;width:100%;height:auto}
.yt-play{position:absolute;inset:0;display:flex;align-items:center;justify-content:center}
.yt-play span{background:rgba(255,255,255,0.9);border-radius:999px;width:60px;height:60px;display:flex;align-items:center;justify-content:center;color:#111;font-weight:700}

/* Subtle polish */
.card:hover .card-inner{transition:transform .2s ease;}
.card:hover{box-shadow:0 10px 30px rgba(0,0,0,.28)}