/* css as of 13/5/26 */

:root {
    --bg: #050508;
    --text: #f3f4f6;
    --muted: #9ca3af;
    --muter: #6b7280;
    --border: #272a33;
    --box: #0f1a2e;
    --box-border: #1e3a5f;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { min-height: 100%; }
body {
    font-family: "Inter", system-ui, sans-serif;
    color: var(--text);
    background: #000000;
}
a { color: inherit; text-decoration: none; }
.bg-grid {
    position: fixed;
    inset: 0;
    background-image:
    linear-gradient(to right, #151821 1px, transparent 1px),
    linear-gradient(to bottom, #151821 1px, transparent 1px);
    background-size: 72px 72px;
    opacity: 0.35;
    pointer-events: none;
    z-index: -2;
}
.bg-fade {
    position: fixed;
    inset: 0;
    background: radial-gradient(circle at top, #050711 0, #000000 55%);
    box-shadow: inset 0 0 160px #000000;
    pointer-events: none;
    z-index: -1;
}
.shell {
    min-height: 100vh;
    display: grid;
    grid-template-columns: 180px 1fr;
}
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: 180px;
    height: 100vh;
    border-right: 1px solid var(--border);
    background: linear-gradient(to bottom, #050711, #050508);
    overflow-y: auto;
    padding: 1rem;
    z-index: 20;
}
.sidebar-title {
    font-size: 0.7rem;
    font-weight: 500;
    text-transform: lowercase;
    letter-spacing: 0.1em;
    color: var(--text);
    margin-bottom: 1rem;
}
.sidebar-back {
    font-size: 0.7rem;
    color: var(--muter);
    display: block;
    margin-bottom: 1.2rem;
    transition: color 0.15s;
}
.sidebar-back:hover {
    color: var(--muted);
}
.nav-item {
    padding: 0.5rem 0.8rem;
    border-left: 2px solid transparent;
    cursor: pointer;
    font-size: 0.7rem;
    color: var(--muted);
    text-transform: lowercase;
    transition: all 0.15s;
    margin-bottom: 0.3rem;
    display: block;
}
.nav-item:hover {
    color: var(--text);
    background: rgba(96, 212, 255, 0.08);
}
.nav-item.active {
    color: var(--text);
    border-left-color: #60d4ff;
    background: rgba(96, 212, 255, 0.08);
}
.content {
    grid-column: 2;
    overflow-y: auto;
    padding: 2rem 1.5rem;
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}
.topic-num {
    font-size: 0.7rem;
    color: var(--muter);
    text-transform: lowercase;
    letter-spacing: 0.1em;
    margin-bottom: 0.5rem;
}
.title {
    font-size: 1.8rem;
    font-weight: 400;
    color: var(--text);
    margin-bottom: 1.5rem;
    text-transform: lowercase;
}
.concept {
    border: 1px solid var(--box-border);
    background: var(--box);
    border-radius: 10px;
    padding: 1.2rem;
    margin-bottom: 1.8rem;
    display: flex;
    gap: 1rem;
}
.atom {
    width: 32px;
    height: 32px;
    flex-shrink: 0;
    border-radius: 999px;
    border: 1px solid #60d4ff;
    background: radial-gradient(circle at 50% 35%, #1a3a4a, #050508);
    position: relative;
}
.atom::before,
.atom::after {
    content: "";
    position: absolute;
    inset: 6px;
    border-radius: 50%;
    border: 0.5px solid rgba(96, 212, 255, 0.5);
    border-left: transparent;
    border-bottom: transparent;
    animation: rot 3s linear infinite;
}
.atom::after {
    border-top: transparent;
    border-right: transparent;
    animation: rot-rev 3s linear infinite;
}
.atom-dot {
    position: absolute;
    width: 4px;
    height: 4px;
    background: #60d4ff;
    border-radius: 999px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 1;
}
@keyframes rot { to { transform: rotate(360deg); } }
@keyframes rot-rev { to { transform: rotate(-360deg); } }
.concept h3 {
    font-size: 0.9rem;
    font-weight: 600;
    color: #60d4ff;
    margin-bottom: 0.5rem;
    text-transform: lowercase;
}
.concept p {
    font-size: 0.82rem;
    color: var(--muted);
    line-height: 1.6;
    text-transform: lowercase;
}
.concept ul {
    margin: 0.6rem 0 0 1rem;
    font-size: 0.8rem;
    color: var(--muted);
    line-height: 1.6;
    text-transform: lowercase;
}
.concept li { margin-bottom: 0.3rem; }
.section { margin-bottom: 1.8rem; }
.section h2 {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text);
    margin-bottom: 0.7rem;
    text-transform: lowercase;
}
.section h3 {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text);
    margin-bottom: 0.6rem;
    text-transform: lowercase;
    margin-top: 1rem;
}
.section p {
    font-size: 0.82rem;
    color: var(--muted);
    line-height: 1.7;
    margin-bottom: 0.6rem;
}
.section ul {
    margin-left: 1.2rem;
    font-size: 0.8rem;
    color: var(--muted);
    line-height: 1.7;
    text-transform: lowercase;
}
.section li { margin-bottom: 0.4rem; }
code {
    font-family: monospace;
    background: rgba(15, 23, 42, 0.9);
    padding: 0.15rem 0.4rem;
    border-radius: 3px;
    font-size: 0.75em;
    color: #a1e0ff;
}
strong { color: var(--text); font-weight: 600; }
.section img {
    max-width: 60%;
    height: auto;
    display: block;
    padding: 2em;
    margin: 3rem auto;
    border-radius: 8px;
    border: 1px solid var(--box-border);
}

/* tables */
table {
width: 100%;
border-collapse: collapse;
margin: 1rem 0 1.6rem;
font-size: 0.78rem;
color: var(--text);
}

thead {
border-bottom: 1px solid var(--border);
}

thead th {
text-align: left;
font-weight: 500;
color: var(--muted);
padding: 0.6rem 0.4rem;
text-transform: lowercase;
letter-spacing: 0.04em;
}

tbody tr {
transition: background 0.12s ease;
}

tbody tr:hover {
background: rgba(96, 212, 255, 0.04);
}

tbody td {
padding: 0.5rem 0.4rem;
border-bottom: 1px solid var(--border);
vertical-align: middle;
}

/* narrow number column */
table td:first-child,
table th:first-child {
width: 48px;
color: var(--muter);
}

/* inline code inside tables */
table code {
font-size: 0.72rem;
padding: 0.12rem 0.35rem;
background: rgba(15, 23, 42, 0.85);
border: 1px solid var(--box-border);
}

/* optional: subtle rounding illusion */
table tbody tr:last-child td {
border-bottom: none;
}

/* vertical column dividers */
thead th:not(:last-child),
tbody td:not(:last-child) {
border-right: 1px solid #222222;
}