:root{--primary-color: #5e35b1;--secondary-color: #03a9f4;--accent-color: #ff4081;--text-color: #f1f1f1;--bg-color: #121212;--card-bg-color: #1e1e1e;--card-shadow: 0 4px 20px rgba(0, 0, 0, .3);--header-bg-color: rgba(18, 18, 18, .9);--section-padding: 5rem 0;--font-family: "Poppins", sans-serif;--primary-rgb: 94, 53, 177;--secondary-rgb: 3, 169, 244;--accent-rgb: 255, 64, 129;--bg-rgb: 18, 18, 18;--space-bg-gradient: linear-gradient(to bottom, #0b0b1a, #121224, #16172a);--space-dust-color: rgba(58, 27, 94, .1);--nebula-glow: rgba(94, 53, 177, .15)}:root[data-font=vi]{--font-family: "Kanit", sans-serif}:root[data-theme=light]{--primary-color: #5e35b1;--secondary-color: #03a9f4;--accent-color: #ff4081;--text-color: #333333;--bg-color: #030714;--card-bg-color: rgba(31, 31, 45, .7);--card-shadow: 0 4px 20px rgba(0, 0, 0, .2);--header-bg-color: rgba(15, 15, 30, .85);--primary-rgb: 94, 53, 177;--secondary-rgb: 3, 169, 244;--accent-rgb: 255, 64, 129;--bg-rgb: 3, 7, 20}[data-theme=dark]{--primary-color: #7c4dff;--secondary-color: #00bcd4;--accent-color: #ff5252;--text-color: #f1f1f1;--bg-color: #121212;--card-bg-color: #1e1e1e;--card-shadow: 0 4px 20px rgba(0, 0, 0, .3);--header-bg-color: rgba(18, 18, 18, .9);--primary-rgb: 124, 77, 255;--secondary-rgb: 0, 188, 212;--accent-rgb: 255, 82, 82;--bg-rgb: 18, 18, 18}*{margin:0;padding:0;box-sizing:border-box}html{scroll-behavior:smooth}body{font-family:var(--font-family);background:var(--space-bg-gradient);color:var(--text-color);line-height:1.6;overflow-x:hidden;transition:background-color .3s ease,color .3s ease,font-family .3s ease;min-height:100vh}a{text-decoration:none;color:var(--primary-color)}.container{max-width:1200px;margin:0 auto;padding:0 1.5rem}.btn{display:inline-block;padding:12px 28px;background-color:var(--primary-color);color:#fff;border:none;border-radius:30px;font-weight:600;cursor:pointer;transition:all .3s ease;box-shadow:0 4px 15px #5e35b14d}.btn:hover{transform:translateY(-2px);box-shadow:0 6px 20px #5e35b166}.btn:active{transform:translateY(1px)}.btn-secondary{background-color:var(--secondary-color);box-shadow:0 4px 15px #03a9f44d}.btn-secondary:hover{box-shadow:0 6px 20px #03a9f466}.btn-outline{background-color:transparent;border:2px solid var(--primary-color);color:var(--primary-color);box-shadow:none}.btn-outline:hover{background-color:var(--primary-color);color:#fff}.section-title{font-size:2.5rem;margin-bottom:1.5rem;font-weight:700;text-align:center;position:relative}.section-title:after{content:"";display:block;width:100px;height:5px;background:linear-gradient(to right,var(--primary-color),var(--secondary-color));margin:.5rem auto;border-radius:5px}.section-subtitle{text-align:center;margin-bottom:3rem;font-size:1.2rem;color:var(--text-color);opacity:.8;max-width:700px;margin-left:auto;margin-right:auto}.fade-in{opacity:0;transform:translateY(30px);transition:opacity .8s ease,transform .8s ease}.fade-in.visible{opacity:1;transform:translateY(0)}@media (max-width: 768px){.section-title{font-size:2rem}.btn{padding:10px 20px}}