:root { --bg: #0f172a; --card: #1e293b; --text: #f8fafc; --accent: #38bdf8; --error: #ef4444; }
body { background: var(--bg); color: var(--text); font-family: sans-serif; display: flex; justify-content: center; align-items: center; height: 100vh; margin: 0; }
.card { background: var(--card); padding: 2rem; border-radius: 8px; width: 300px; text-align: center; box-shadow: 0 10px 15px rgba(0,0,0,0.5); }
input { width: 90%; padding: 10px; margin: 10px 0; background: var(--bg); border: 1px solid #334155; color: white; border-radius: 4px; }
button { width: 100%; padding: 10px; margin: 5px 0; background: var(--accent); border: none; font-weight: bold; border-radius: 4px; cursor: pointer; color: #0f172a; }
.logout-btn { background: transparent; border: 1px solid var(--accent); color: var(--accent); }
.error { color: var(--error); font-size: 0.9em; }
.balance-box { background: #0284c7; padding: 1rem; border-radius: 4px; margin-bottom: 1rem; }