* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 480px;
    margin: 0 auto;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
header {
    background: linear-gradient(to right, #4facfe 0%, #00f2fe 100%);
    color: white;
    padding: 20px;
    text-align: center;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

header h1 {
    margin: 0;
    font-size: 1.6em;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.user-info {
    margin: 15px 0 20px;
    font-size: 1.1em;
}

.uid-display {
    background: rgba(255, 255, 255, 0.2);
    padding: 10px;
    border-radius: 10px;
    margin: 10px 0;
    word-break: break-all;
    font-family: monospace;
    font-size: 0.9em;
}

.balance-display {
    font-size: 1.8em;
    font-weight: bold;
    margin: 10px 0;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* Nút chính */
.main-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 20px;
}

.btn-3d {
    padding: 14px 20px;
    font-size: 1em;
    font-weight: bold;
    color: white;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.3);
    transition: all 0.3s ease;
    flex: 1;
}

.btn-3d:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.4);
}

.btn-3d:active {
    transform: translateY(2px);
}

.btn-voucher { background: linear-gradient(to bottom, #ff9a00, #ff6b00); }
.btn-send    { background: linear-gradient(to bottom, #6f42c1, #5a32a3); }
.btn-receive { background: linear-gradient(to bottom, #fd7e14, #e66a0e); }

/* Body */
main {
    flex: 1;
    padding: 20px;
}

/* Chào mừng */
#welcome-message {
    text-align: center;
    padding: 20px;
    background: linear-gradient(to right, #a8edea 0%, #fed6e3 100%);
    border-radius: 12px;
    margin: 20px;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
    animation: fadeIn 1.5s ease-in;
}

#welcome-message h2 {
    margin: 0 0 10px;
    color: #333;
    font-size: 1.5em;
}

#welcome-message p {
    margin: 8px 0;
    color: #555;
}

#welcome-message p:last-child {
    font-size: 0.9em;
    color: #777;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* QR Code */
#qrcode {
    text-align: center;
    margin: 30px 0;
}

#qrcode canvas {
    padding: 30px;
    background: white;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

/* Lịch sử */
#txhash {
    margin-top: 20px;
}

.history-item {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 12px;
    margin: 12px 0;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    border-left: 5px solid #007bff;
}

.history-reward   { border-left-color: #28a745; background: #d4edda; }
.history-send     { border-left-color: #dc3545; background: #f8d7da; }
.history-receive  { border-left-color: #28a745; background: #d4edda; }

/* Footer */
footer {
    background: #333;
    color: #aaa;
    text-align: center;
    padding: 20px;
    font-size: 0.9em;
}

.footer-actions {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 15px;
}

.btn-footer {
    background: #555;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    transition: all 0.3s;
}

.btn-footer:hover {
    background: #666;
    transform: translateY(-3px);
}

/* Ẩn input file */
input[type="file"] {
    display: none;
}
#txhash .history-item {
    animation: fadeIn 0.6s ease-in;
}