:root{--bg-dark: #0a0e14;--bg-panel: #161b22;--bg-input: #0d1117;--primary: #00ff9d;--primary-dim: rgba(0, 255, 157, .1);--secondary: #00f0ff;--accent: #ff0055;--text-main: #e6edf3;--text-muted: #8b949e;--border-color: #30363d;--grade-s: #d946ef;--grade-a: #00ff9d;--grade-b: #38bdf8;--grade-c: #fbbf24;--grade-d: #ef4444;--font-mono: "JetBrains Mono", "Fira Code", Consolas, monospace;--font-sans: "Inter", system-ui, -apple-system, sans-serif}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--bg-dark);color:var(--text-main);font-family:var(--font-sans);line-height:1.6;-webkit-font-smoothing:antialiased}a{color:var(--primary);text-decoration:none;transition:opacity .2s}a:hover{opacity:.8}button{cursor:pointer;font-family:var(--font-mono)}.container{max-width:1200px;margin:0 auto;padding:2rem}.mono{font-family:var(--font-mono)}.grade-s{color:#00ff9d;text-shadow:0 0 10px rgba(0,255,157,.5)}.grade-a{color:#00f0ff}.grade-b{color:#ffbf00}.grade-c{color:#f90}@keyframes fadeIn{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.animate-in{animation:fadeIn .4s ease-out forwards}.flip-card-container{perspective:1000px;height:100%}.flip-card-inner{position:relative;width:100%;height:100%;text-align:center;transition:transform .6s cubic-bezier(.4,0,.2,1);transform-style:preserve-3d}.flip-card-container:hover .flip-card-inner{transform:rotateY(180deg)}.flip-card-front,.flip-card-back{position:absolute;width:100%;height:100%;-webkit-backface-visibility:hidden;backface-visibility:hidden;border-radius:12px;overflow:hidden}.flip-card-front{background:var(--bg-panel);border:1px solid var(--border-color);transition:border-color .3s ease,box-shadow .3s ease}.flip-card-container:hover .flip-card-front{border-color:var(--tier-dim);box-shadow:0 0 15px var(--tier-shadow)}.flip-card-back{background:var(--bg-input);border:1px solid var(--tier-main);color:var(--text-main);transform:rotateY(180deg);display:flex;flex-direction:column;justify-content:center;align-items:center;padding:1.5rem;box-shadow:0 0 35px var(--tier-shadow)}.flip-card-back h4{color:var(--tier-main)!important;border-bottom-color:var(--tier-dim)!important}