:root { --primary: #2563eb; --sidebar-bg: #ffffff; }
        body { font-family: 'Plus Jakarta Sans', sans-serif; background: #f8fafc; color: #1e293b; overflow-x: hidden; }
        .sidebar { background: var(--sidebar-bg); min-height: 100vh; border-right: 1px solid #e2e8f0; position: sticky; top: 0; }
        .nav-link { padding: 1rem 1.5rem; color: #64748b; border-radius: 12px; margin: 0.2rem 1rem; transition: 0.2s; border: none; background: none; text-align: left; width: calc(100% - 2rem); font-weight: 500; }
        .nav-link.active { background: #eff6ff; color: var(--primary); font-weight: 700; }
        .content-card { background: #fff; border-radius: 24px; padding: 2.5rem; border: 1px solid #e2e8f0; box-shadow: 0 4px 12px rgba(0,0,0,0.03); }
        
        /* Chat UI International Style */
        #chat-window { position: fixed; bottom: 100px; right: 30px; width: 350px; height: 500px; background: #fff; border-radius: 24px; box-shadow: 0 20px 25px -5px rgba(0,0,0,0.1); display: none; flex-direction: column; z-index: 2000; border: 1px solid #e2e8f0; overflow: hidden; }
        #chat-header { background: var(--primary); color: #fff; padding: 1.2rem; font-weight: 700; display: flex; justify-content: space-between; align-items: center; }
        #chat-messages { flex: 1; overflow-y: auto; padding: 1.5rem; display: flex; flex-direction: column; gap: 0.8rem; background: #fcfcfc; }
        .msg { padding: 0.8rem 1rem; border-radius: 18px; font-size: 0.9rem; max-width: 85%; line-height: 1.4; }
        .msg-ai { background: #f1f5f9; color: #1e293b; align-self: flex-start; border-bottom-left-radius: 4px; }
        .msg-user { background: var(--primary); color: #fff; align-self: flex-end; border-bottom-right-radius: 4px; }
        #chat-trigger { position: fixed; bottom: 30px; right: 30px; width: 64px; height: 64px; background: var(--primary); color: #fff; border-radius: 50%; display: flex; align-items: center; justify-content: center; cursor: pointer; box-shadow: 0 10px 15px rgba(37,99,235,0.4); border: none; font-size: 1.5rem; z-index: 2001; }