@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700;800&display=swap');

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

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #0a0e27 0%, #1a1e3f 50%, #2a2e4f 100%);
    min-height: 100vh;
    padding-bottom: 3rem;
}

/* Navbar */
.navbar {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding: 1rem 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

.navbar-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Container */
.container {
    max-width: 1000px;
    margin: 2rem auto;
    padding: 0 1rem;
}

/* Top Up Section */
.topup-section {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: 2.5rem;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.back-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(255, 255, 255, 0.1);
    color: white;
    padding: 0.6rem 1.5rem;
    border-radius: 25px;
    text-decoration: none;
    margin-bottom: 1.5rem;
    transition: all 0.3s;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.back-button:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateX(-5px);
}

h2 {
    color: white;
    font-size: 2rem;
    margin-bottom: 2rem;
    font-weight: 700;
}

/* Form Groups */
.form-group {
    margin-bottom: 2rem;
}

.form-label {
    display: block;
    font-weight: 600;
    color: white;
    margin-bottom: 0.8rem;
    font-size: 1.05rem;
}

.form-input {
    width: 100%;
    padding: 1rem;
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    font-size: 1rem;
    background: rgba(255, 255, 255, 0.05);
    color: white;
    transition: all 0.3s;
}

.form-input:focus {
    outline: none;
    border-color: #667eea;
    background: rgba(255, 255, 255, 0.1);
}

.form-input::placeholder {
    color: rgba(255, 255, 255, 0.4);
}

.input-group {
    display: flex;
    gap: 0.8rem;
}

.input-group input {
    flex: 1;
}

/* Button Check */
.btn-check {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 1rem 1.8rem;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    white-space: nowrap;
    transition: all 0.3s;
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.3);
}

.btn-check:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.5);
}

.btn-check:disabled {
    background: rgba(255, 255, 255, 0.1);
    cursor: not-allowed;
    box-shadow: none;
}

/* Nickname Display */
.nickname-display {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 12px;
    display: none;
    animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.nickname-display.success {
    display: block;
    background: rgba(76, 175, 80, 0.2);
    color: #4caf50;
    border: 2px solid rgba(76, 175, 80, 0.5);
}

.nickname-display.error {
    display: block;
    background: rgba(244, 67, 54, 0.2);
    color: #f44336;
    border: 2px solid rgba(244, 67, 54, 0.5);
}

.nickname-display.warning {
    display: block;
    background: rgba(255, 152, 0, 0.2);
    color: #ff9800;
    border: 2px solid rgba(255, 152, 0, 0.5);
}

/* Packages Grid */
.packages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.package-item {
    position: relative;
}

.package-item input[type="radio"] {
    position: absolute;
    opacity: 0;
}

.package-item label {
    display: block;
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: 15px;
    padding: 1.2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
}

.package-item label:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(102, 126, 234, 0.5);
    transform: translateY(-3px);
}

.package-item input[type="radio"]:checked + label {
    border-color: #667eea;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.3) 0%, rgba(118, 75, 162, 0.3) 100%);
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.4);
}

.package-amount {
    font-size: 1.3rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
    color: white;
}

.package-price {
    font-size: 0.95rem;
    color: rgba(255, 255, 255, 0.7);
}

/* Payment Methods */
.payment-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.payment-item {
    position: relative;
}

.payment-item input[type="radio"] {
    position: absolute;
    opacity: 0;
}

.payment-item label {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.8rem;
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: 15px;
    padding: 1.2rem;
    cursor: pointer;
    transition: all 0.3s;
    color: white;
}

.payment-item label:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(102, 126, 234, 0.5);
    transform: translateY(-3px);
}

.payment-item input[type="radio"]:checked + label {
    border-color: #667eea;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.3) 0%, rgba(118, 75, 162, 0.3) 100%);
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.4);
}

.payment-item img {
    width: 60px;
    height: 60px;
    object-fit: contain;
    filter: brightness(0.9);
}

/* Button Top Up */
.btn-topup {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 1.2rem 2rem;
    border-radius: 15px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    width: 100%;
    transition: all 0.3s;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

.btn-topup:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.6);
}

.btn-topup:disabled {
    background: rgba(255, 255, 255, 0.1);
    cursor: not-allowed;
    box-shadow: none;
}

/* Alert */
.alert-error {
    background: rgba(244, 67, 54, 0.2);
    color: #f44336;
    border: 2px solid rgba(244, 67, 54, 0.5);
    padding: 1rem;
    border-radius: 12px;
    margin-bottom: 1.5rem;
}

/* Loading Animation */
.loading {
    display: inline-block;
    width: 18px;
    height: 18px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Responsive */
@media (max-width: 768px) {
    .topup-section {
        padding: 1.5rem;
    }

    .packages-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .payment-methods {
        grid-template-columns: repeat(2, 1fr);
    }
}