body{margin:0}:root{--bg-color:#fff;--text-color:#333;--primary-color:#07f;--secondary-color:#05c;--section-bg:#f9f9f9}.dark-mode{--bg-color:#121212;--text-color:#f1f1f1;--primary-color:#bb86fc;--secondary-color:#3700b3;--section-bg:#1e1e1e}.app-container{background-color:var(--bg-color);color:var(--text-color);min-height:100vh;font-family:Arial,sans-serif;transition:background-color .3s,color .3s}header{background:var(--section-bg);z-index:1000;justify-content:space-between;align-items:center;padding:20px 50px;display:flex;position:sticky;top:0}.logo{font-size:24px;font-weight:700}nav ul{align-items:center;gap:20px;margin:0;padding:0;list-style:none;display:flex}nav a{color:var(--text-color);text-decoration:none}section{text-align:center;padding:60px 50px}section:nth-child(2n){background-color:var(--section-bg)}button,.btn{background:var(--primary-color);color:#fff;cursor:pointer;border:none;border-radius:5px;padding:10px 20px;text-decoration:none;transition:background .3s;display:inline-block}button:hover,.btn:hover{background:var(--secondary-color)}.skills-container,.projects-container{flex-wrap:wrap;justify-content:center;gap:20px;margin-top:20px;display:flex}.skill{background:var(--primary-color);color:#fff;border-radius:8px;padding:15px 30px;font-weight:700}.project-card{background:var(--section-bg);border:1px solid #ddd;border-radius:8px;width:300px;padding:20px;box-shadow:0 4px 6px #0000001a}.contact-form{flex-direction:column;gap:15px;max-width:400px;margin:0 auto;display:flex}.contact-form input,.contact-form textarea{border:1px solid #ccc;border-radius:4px;padding:10px}.contact-form textarea{height:100px}@media (width<=768px){header{flex-direction:column;padding:20px}nav ul{flex-direction:column;gap:10px;margin-top:15px}section{padding:30px 20px}}