body{margin:0;padding:0;font-family:Arial,sans-serif;background-color:#f0e6ff}.container{max-width:700px;margin:20px auto;background:#f5f6fa;padding:30px;border-radius:8px;box-shadow:0 0 10px #0000001a;transition:background .3s,color .3s}h1{text-align:center;background:linear-gradient(90deg,#1d52e2,#00c6ff)}.book-list{list-style:none;padding:0}.book-list li{margin:10px 0}.book-list a{text-decoration:none;color:#007acc;font-weight:700}.book-list a:hover{background:linear-gradient(90deg,#1d52e2,#00c6ff);color:#fff;text-decoration:underline}.theme-toggle{text-align:right;padding:10px 20px}.theme-toggle button{padding:8px 16px;font-size:14px;cursor:pointer;border:none;border-radius:5px;background:#7bc6f8;color:#fff;transition:background .3s}.theme-toggle button:hover{background:#005f99}.dark-mode{background:#282c34;color:#3da2e6;min-height:100vh}.dark-mode .container{background:#23272f;color:#f0f0f0}.dark-mode .book-list a{color:#b2c5e9}.dark-mode .book-list a:hover{color:#8be9fd}.dark-mode .theme-toggle button{background:#4b4949;color:#f0f0f0}.dark-mode .theme-toggle button:hover{background:#666}.header{background:linear-gradient(90deg,#1d52e2,#00c6ff);padding:15px;color:#fff;text-align:center;font-size:24px;font-weight:700;box-shadow:0 2px 4px #0000001a;transition:background .3s,color .3s}.logo{height:40px;vertical-align:middle;margin-right:10px}