/* RESET & BASE */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 500px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    overflow: hidden;
    padding: 0;
}

/* HEADER */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 24px;
    font-weight: bold;
}

.logo i {
    font-size: 28px;
}

.user-menu {
    background: rgba(255,255,255,0.2);
    padding: 8px 15px;
    border-radius: 50px;
    font-size: 14px;
}

/* BALANCE CARD */
.balance-card {
    background: linear-gradient(135deg, #4CAF50 0%, #2E7D32 100%);
    color: white;
    margin: 20px;
    padding: 25px;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(76, 175, 80, 0.3);
}

.balance-label {
    font-size: 14px;
    opacity: 0.9;
    margin-bottom: 10px;
}

.balance-amount {
    font-size: 42px;
    font-weight: bold;
    margin: 10px 0;
}

.balance-update {
    font-size: 12px;
    opacity: 0.8;
}

/* SECTIONS */
.section {
    padding: 0 20px;
    margin: 25px 0;
}

.section h2 {
    color: #333;
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 18px;
}

/* QUICK AMOUNTS */
.quick-amounts {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-top: 10px;
}

.amount-btn {
    padding: 15px;
    border: 2px solid #e0e0e0;
    background: white;
    border-radius: 10px;
    font-weight: bold;
    color: #333;
    cursor: pointer;
    transition: all 0.3s;
}

.amount-btn:hover {
    border-color: #667eea;
    color: #667eea;
}

.amount-btn.active {
    background: #667eea;
    color: white;
    border-color: #667eea;
}

/* CUSTOM AMOUNT */
.custom-amount {
    margin-top: 15px;
}

.input-group {
    display: flex;
    align-items: center;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 5px;
}

.input-prefix {
    padding: 0 15px;
    background: #f5f5f5;
    height: 50px;
    display: flex;
    align-items: center;
    font-weight: bold;
    color: #666;
}

#customAmount {
    flex: 1;
    border: none;
    padding: 15px;
    font-size: 16px;
    outline: none;
}

.hint {
    color: #666;
    font-size: 12px;
    display: block;
    margin-top: 5px;
}

/* PAYMENT METHODS */
.payment-methods {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-top: 15px;
}

.method-card {
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    padding: 15px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
}

.method-card:hover {
    border-color: #667eea;
}

.method-card.active {
    border-color: #667eea;
    background: #f0f4ff;
}

.method-card i {
    font-size: 24px;
    color: #667eea;
    margin-bottom: 10px;
    display: block;
}

.method-card span {
    display: block;
    font-weight: bold;
    margin-bottom: 5px;
}

.method-card small {
    color: #666;
    font-size: 12px;
}

/* ACTION BUTTONS */
.action-section {
    padding: 20px;
    border-top: 1px solid #eee;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 18px;
    border-radius: 12px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    transition: transform 0.2s;
}

.btn-primary:hover {
    transform: translateY(-2px);
}

.btn-secondary {
    background: white;
    color: #667eea;
    border: 2px solid #667eea;
    padding: 15px;
    border-radius: 12px;
    font-size: 14px;
    font-weight: bold;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

/* MODAL */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal-content {
    background: white;
    border-radius: 20px;
    width: 100%;
    max-width: 400px;
    overflow: hidden;
    animation: modalSlide 0.3s;
}

@keyframes modalSlide {
    from { transform: translateY(-50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.modal-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.close-modal {
    background: none;
    border: none;
    color: white;
    font-size: 28px;
    cursor: pointer;
    line-height: 1;
}

.modal-body {
    padding: 30px;
    text-align: center;
}

/* RESPONSIVE */
@media (max-width: 480px) {
    .quick-amounts {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .payment-methods {
        grid-template-columns: 1fr;
    }
    
    .balance-amount {
        font-size: 36px;
    }
}