:root {
    --bg-dark: #000000;
    --panel-bg: #000000;
    --primary-red: #ff1e1e;
    --glow-red: rgba(255, 30, 30, 0.5);
    --text-main: #f0f0f0;
    --text-muted: #888;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Inter', 'Segoe UI', sans-serif; }
body { background-color: var(--bg-dark); color: var(--text-main); line-height: 1.8; background-size: cover; background-position: center; background-attachment: fixed; overflow-x: hidden; min-height: 100vh; transition: background-color 0.3s; }

::-webkit-scrollbar { width: 12px; }
::-webkit-scrollbar-track { background: #000; }
::-webkit-scrollbar-thumb { background: #333; border-radius: 6px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-red); }

.nav { background: rgba(0, 0, 0, 0.9); backdrop-filter: blur(10px); height: 80px; display: flex; align-items: center; padding: 0 40px; border-bottom: 2px solid var(--primary-red); position: fixed; top: 0; width: 100%; z-index: 1000; box-shadow: 0 4px 30px rgba(0,0,0,0.8); }
.nav b { font-size: 1.5rem; letter-spacing: 4px; color: var(--primary-red); text-shadow: 0 0 15px var(--glow-red); }

.container { display: block; margin-top: 80px; width: 100%; }

.sidebar { background: rgba(5, 5, 5, 0.95); border-right: 1px solid #222; padding: 40px 20px; display: flex; flex-direction: column; gap: 15px; position: fixed; width: 320px; height: calc(100vh - 80px); top: 80px; left: 0; z-index: 100; overflow-y: auto; }
.sidebar a { display: block; color: var(--text-muted); padding: 20px 25px; text-decoration: none; font-weight: 800; font-size: 1.1rem; border-radius: 12px; transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1); letter-spacing: 2px; text-transform: uppercase; background: transparent; cursor: pointer; }
.sidebar a:hover, .sidebar a.active { color: #fff; background: rgba(255, 30, 30, 0.1); padding-left: 35px; box-shadow: inset 4px 0 0 var(--primary-red); }

.content-area { padding: 60px 80px; margin-left: 320px; width: calc(100% - 320px); max-width: 1600px; min-height: calc(100vh - 80px); animation: fadeUp 0.8s ease-out; }
@keyframes fadeUp { 0% { opacity: 0; transform: translateY(30px); } 100% { opacity: 1; transform: translateY(0); } }

.box { background: var(--panel-bg); border: 1px solid #2a2a35; border-radius: 16px; padding: 50px 60px; margin-bottom: 20px; box-shadow: 0 20px 50px rgba(0,0,0,0.8); position: relative; overflow: hidden; }
.box::before { content: ''; position: absolute; top: 0; left: 0; width: 6px; height: 100%; background: var(--primary-red); box-shadow: 0 0 20px var(--primary-red); }

.explanation-box { background: rgba(255, 30, 30, 0.03); border: 1px dashed #444; border-left: 6px solid #880000; border-radius: 0 0 16px 16px; padding: 30px 60px; margin-top: 0px; margin-bottom: 60px; }
.explanation-box h3 { color: var(--primary-red); font-size: 1.5rem; margin-bottom: 15px; letter-spacing: 1px; }

h1 { font-size: 3.5rem; font-weight: 900; letter-spacing: -2px; margin-bottom: 40px; text-transform: uppercase; color: #fff; text-shadow: 2px 2px 10px rgba(0,0,0,0.8); line-height: 1.2; }
h2 { color: var(--primary-red); font-size: 2rem; font-weight: 800; margin-bottom: 25px; letter-spacing: -1px; }
p { font-size: 1.15rem; margin-bottom: 20px; color: #ccc; text-align: justify; line-height: 1.7; }

.slider-container { margin-bottom: 30px; }
.slider-container label { display: block; font-size: 1.2rem; font-weight: bold; margin-bottom: 15px; color: #fff; }
input[type="range"] { -webkit-appearance: none; width: 100%; height: 8px; background: #222; border-radius: 5px; outline: none; transition: 0.2s; }
input[type="range"]::-webkit-slider-thumb { -webkit-appearance: none; appearance: none; width: 25px; height: 25px; border-radius: 50%; background: var(--primary-red); cursor: pointer; box-shadow: 0 0 15px var(--primary-red); }
select { background: #111; color: #fff; padding: 15px; font-size: 1.2rem; border: 2px solid var(--primary-red); border-radius: 8px; width: 100%; cursor: pointer; outline: none; margin-bottom: 20px; }

.formula { background: #000; padding: 20px; border-left: 4px solid var(--primary-red); font-family: monospace; font-size: 1.4rem; color: #fff; margin-bottom: 30px; text-align: center; letter-spacing: 2px; }

.support-link { display: block; background: #111; border: 2px solid #333; padding: 30px; border-radius: 12px; text-decoration: none; color: #fff; transition: 0.3s; margin-bottom: 20px; cursor: pointer; width: 100%; text-align: left; }
.support-link:hover { border-color: var(--primary-red); transform: translateY(-5px); box-shadow: 0 10px 30px rgba(255,30,30,0.2); }
.support-link h3 { color: var(--primary-red); font-size: 2rem; margin-bottom: 10px; }