:root {
    --pc-bg: #020f1c;
    --pc-bg-2: #0a1a2e;
    --pc-surface: rgba(14, 28, 48, 0.72);
    --pc-border: rgba(44, 146, 242, 0.18);
    --pc-accent: #2c92f2;
    --pc-accent-2: #af6cf3;
    --pc-text: #e8eef7;
    --pc-muted: #8b9cb3;
    --pc-warn: #f59e0b;
    --pc-danger: #ef4444;
    --pc-radius: 18px;
    --pc-font: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    min-height: 100vh;
    font-family: var(--pc-font);
    color: var(--pc-text);
    background: var(--pc-bg);
    overflow-x: hidden;
    line-height: 1.65;
}

.pc-bg {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    background:
        radial-gradient(ellipse 80% 50% at 20% -10%, rgba(44, 146, 242, 0.22), transparent 55%),
        radial-gradient(ellipse 60% 40% at 90% 10%, rgba(175, 108, 243, 0.16), transparent 50%),
        linear-gradient(180deg, #020f1c 0%, #061525 50%, #020a12 100%);
}

.pc-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(60px);
    opacity: 0.45;
    animation: pc-float 14s ease-in-out infinite;
}

.pc-orb-1 { width: 280px; height: 280px; background: #2c92f2; top: 8%; left: -4%; }
.pc-orb-2 { width: 220px; height: 220px; background: #af6cf3; top: 42%; right: -6%; animation-delay: -5s; }
.pc-orb-3 { width: 160px; height: 160px; background: #0ea5e9; bottom: 12%; left: 30%; animation-delay: -9s; }

@keyframes pc-float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(18px, -22px) scale(1.06); }
}

.pc-stars {
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(1px 1px at 10% 20%, rgba(255,255,255,0.5), transparent),
        radial-gradient(1px 1px at 30% 65%, rgba(255,255,255,0.35), transparent),
        radial-gradient(1.5px 1.5px at 55% 15%, rgba(255,255,255,0.45), transparent),
        radial-gradient(1px 1px at 72% 78%, rgba(255,255,255,0.3), transparent),
        radial-gradient(1px 1px at 88% 35%, rgba(255,255,255,0.4), transparent);
    animation: pc-twinkle 8s ease-in-out infinite alternate;
}

@keyframes pc-twinkle {
    from { opacity: 0.55; }
    to { opacity: 1; }
}

.pc-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    width: 0;
    z-index: 200;
    background: linear-gradient(90deg, var(--pc-accent), var(--pc-accent-2));
    box-shadow: 0 0 12px rgba(44, 146, 242, 0.6);
    transition: width 0.1s linear;
}

.pc-header {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 14px 20px;
    background: rgba(2, 15, 28, 0.82);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--pc-border);
}

.pc-back {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 16px;
    border-radius: 999px;
    border: 1px solid var(--pc-border);
    background: rgba(44, 146, 242, 0.1);
    color: var(--pc-accent);
    text-decoration: none;
    font-size: 14px;
    transition: background 0.2s, transform 0.2s;
}

.pc-back:hover {
    background: rgba(44, 146, 242, 0.2);
    transform: translateX(-2px);
}

.pc-lang {
    display: flex;
    padding: 4px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--pc-border);
}

.pc-lang-btn {
    border: none;
    background: transparent;
    color: var(--pc-muted);
    font-size: 13px;
    font-weight: 600;
    padding: 7px 14px;
    border-radius: 999px;
    cursor: pointer;
    transition: all 0.25s;
    letter-spacing: 0.03em;
}

.pc-lang-btn.active {
    background: linear-gradient(135deg, var(--pc-accent), #1d6fd4);
    color: #fff;
    box-shadow: 0 4px 14px rgba(44, 146, 242, 0.35);
}

.pc-wrap {
    position: relative;
    z-index: 1;
    max-width: 820px;
    margin: 0 auto;
    padding: 28px 20px 64px;
}

.pc-hero {
    text-align: center;
    padding: 36px 20px 40px;
    margin-bottom: 28px;
    border-radius: calc(var(--pc-radius) + 6px);
    background: var(--pc-surface);
    border: 1px solid var(--pc-border);
    backdrop-filter: blur(12px);
    animation: pc-fade-up 0.7s ease both;
}

.pc-hero-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 18px;
    border-radius: 22px;
    display: grid;
    place-items: center;
    font-size: 30px;
    color: #fff;
    background: linear-gradient(135deg, var(--pc-accent), var(--pc-accent-2));
    box-shadow: 0 12px 32px rgba(44, 146, 242, 0.35);
    animation: pc-pulse-icon 3s ease-in-out infinite;
}

@keyframes pc-pulse-icon {
    0%, 100% { transform: scale(1); box-shadow: 0 12px 32px rgba(44, 146, 242, 0.35); }
    50% { transform: scale(1.04); box-shadow: 0 16px 40px rgba(175, 108, 243, 0.4); }
}

.pc-hero h1 {
    margin: 0 0 10px;
    font-size: clamp(26px, 5vw, 34px);
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #fff 30%, #93c5fd 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.pc-hero-sub {
    margin: 0;
    color: var(--pc-muted);
    font-size: 15px;
}

.pc-hero-meta {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin-top: 20px;
}

.pc-pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 12px;
    color: var(--pc-muted);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.pc-pill i { color: var(--pc-accent); font-size: 11px; }

.pc-toc {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 24px;
    animation: pc-fade-up 0.7s 0.1s ease both;
}

.pc-toc a {
    padding: 7px 12px;
    border-radius: 10px;
    font-size: 12px;
    color: var(--pc-muted);
    text-decoration: none;
    border: 1px solid transparent;
    transition: all 0.2s;
}

.pc-toc a:hover {
    color: var(--pc-accent);
    border-color: var(--pc-border);
    background: rgba(44, 146, 242, 0.08);
}

.pc-section {
    margin-bottom: 18px;
    padding: 22px 24px;
    border-radius: var(--pc-radius);
    background: var(--pc-surface);
    border: 1px solid var(--pc-border);
    backdrop-filter: blur(10px);
    opacity: 0;
    transform: translateY(18px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.pc-section.is-visible {
    opacity: 1;
    transform: translateY(0);
}

.pc-section h2 {
    margin: 0 0 14px;
    font-size: 18px;
    font-weight: 600;
    color: #fff;
    display: flex;
    align-items: center;
    gap: 10px;
}

.pc-section h2 .pc-num {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    display: grid;
    place-items: center;
    font-size: 13px;
    font-weight: 700;
    color: var(--pc-accent);
    background: rgba(44, 146, 242, 0.15);
    flex-shrink: 0;
}

.pc-section p {
    margin: 0 0 12px;
    color: rgba(232, 238, 247, 0.88);
    font-size: 15px;
}

.pc-section p:last-child { margin-bottom: 0; }

.pc-section ul {
    margin: 8px 0 12px;
    padding-left: 20px;
    color: rgba(232, 238, 247, 0.88);
    font-size: 15px;
}

.pc-section li { margin: 6px 0; }

.pc-section strong { color: #fff; }

.pc-callout {
    margin: 16px 0 0;
    padding: 14px 16px;
    border-radius: 12px;
    font-size: 14px;
    line-height: 1.55;
}

.pc-callout-warn {
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.28);
    color: #fcd34d;
}

.pc-callout-info {
    background: rgba(44, 146, 242, 0.1);
    border: 1px solid rgba(44, 146, 242, 0.25);
    color: #93c5fd;
}

.pc-callout-danger {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.28);
    color: #fca5a5;
    animation: pc-glow-warn 4s ease-in-out infinite;
}

@keyframes pc-glow-warn {
    0%, 100% { box-shadow: 0 0 0 rgba(239, 68, 68, 0); }
    50% { box-shadow: 0 0 20px rgba(239, 68, 68, 0.15); }
}

.pc-infogrid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 12px;
    margin-top: 14px;
}

.pc-infocard {
    padding: 14px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.07);
}

.pc-infocard-label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--pc-muted);
    margin-bottom: 4px;
}

.pc-infocard-value {
    font-size: 14px;
    font-weight: 600;
    color: #fff;
}

.pc-contact {
    text-align: center;
    padding: 28px 24px;
    border-radius: var(--pc-radius);
    background: linear-gradient(145deg, rgba(44, 146, 242, 0.12), rgba(175, 108, 243, 0.08));
    border: 1px solid var(--pc-border);
    margin-top: 8px;
}

.pc-contact i {
    font-size: 32px;
    color: var(--pc-accent);
    margin-bottom: 12px;
}

.pc-contact h3 {
    margin: 0 0 8px;
    font-size: 18px;
}

.pc-contact a {
    color: var(--pc-accent);
    text-decoration: none;
}

.pc-contact a:hover { text-decoration: underline; }

.pc-footer {
    text-align: center;
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid var(--pc-border);
    font-size: 12px;
    color: var(--pc-muted);
}

.pc-related {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin: 28px 0 8px;
}

.pc-related-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: 999px;
    border: 1px solid var(--pc-border);
    background: rgba(44, 146, 242, 0.1);
    color: var(--pc-accent);
    text-decoration: none;
    font-size: 13px;
    transition: background 0.2s, transform 0.2s;
}

.pc-related-link:hover {
    background: rgba(44, 146, 242, 0.2);
    transform: translateY(-1px);
}

.pc-section a {
    color: var(--pc-accent);
    text-decoration: none;
}

.pc-section a:hover { text-decoration: underline; }

.pc-license-block {
    margin: 14px 0;
    padding: 14px 16px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.07);
}

.pc-license-block h3 {
    margin: 0 0 6px;
    font-size: 15px;
    color: #fff;
}

.pc-license-block p {
    margin: 0;
    font-size: 13px;
    color: var(--pc-muted);
}

@keyframes pc-fade-up {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
}

.pc-content-fade {
    animation: pc-content-swap 0.35s ease;
}

@keyframes pc-content-swap {
    from { opacity: 0; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 600px) {
    .pc-wrap { padding: 16px 14px 48px; }
    .pc-section { padding: 18px 16px; }
    .pc-hero { padding: 28px 16px 32px; }
    .pc-toc { gap: 6px; }
    .pc-toc a { font-size: 11px; padding: 6px 10px; }
}