/* Color Palette Variables - Easy to change */
:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --success-gradient: linear-gradient(135deg, #81ffef 0%, #a8edea 100%);
    
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #4facfe;
    --success-color: #00d4aa;
    --warning-color: #ff6b6b;
    --text-dark: #2d3748;
    --text-light: #718096;
    --text-white: #ffffff;
    
    --bg-primary: #f7fafc;
    --bg-secondary: #ffffff;
    --bg-dark: #1a202c;
    --bg-glass: rgba(255, 255, 255, 0.1);
    
    --shadow-soft: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-medium: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-large: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-neon: 0 0 20px rgba(102, 126, 234, 0.3);
    
    --border-radius: 12px;
    --border-radius-large: 20px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-dark);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Loading Screen */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #4facfe 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    opacity: 1;
    transition: opacity 0.5s ease-out;
}

.loading-screen.fade-out {
    opacity: 0;
    pointer-events: none;
}

.loading-container {
    text-align: center;
    animation: fadeInUp 0.8s ease-out;
}

.loading-brain {
    position: relative;
    width: 80px;
    height: 80px;
    margin: 0 auto 30px;
}

.neural-network {
    position: relative;
    width: 100%;
    height: 100%;
}

.neuron {
    position: absolute;
    width: 12px;
    height: 12px;
    background: var(--text-white);
    border-radius: 50%;
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.8);
}

.neuron-1 {
    top: 10px;
    left: 10px;
    animation: neuronPulse 1.5s ease-in-out infinite;
}

.neuron-2 {
    top: 10px;
    right: 10px;
    animation: neuronPulse 1.5s ease-in-out infinite 0.5s;
}

.neuron-3 {
    bottom: 10px;
    left: 50%;
    transform: translateX(-50%);
    animation: neuronPulse 1.5s ease-in-out infinite 1s;
}

.connection {
    position: absolute;
    background: var(--text-white);
    opacity: 0.6;
    animation: connectionFlow 2s ease-in-out infinite;
}

.connection-1 {
    top: 16px;
    left: 22px;
    width: 36px;
    height: 2px;
    transform: rotate(0deg);
}

.connection-2 {
    top: 22px;
    left: 16px;
    width: 32px;
    height: 2px;
    transform: rotate(60deg);
}

.connection-3 {
    top: 22px;
    right: 16px;
    width: 32px;
    height: 2px;
    transform: rotate(-60deg);
}

.loading-text {
    color: var(--text-white);
    font-size: 24px;
    font-weight: 600;
    letter-spacing: 2px;
}

.loading-letter {
    display: inline-block;
    animation: letterBounce 1.4s ease-in-out infinite;
}

.loading-letter:nth-child(1) { animation-delay: 0.1s; }
.loading-letter:nth-child(2) { animation-delay: 0.2s; }
.loading-letter:nth-child(3) { animation-delay: 0.3s; }
.loading-letter:nth-child(4) { animation-delay: 0.4s; }
.loading-letter:nth-child(5) { animation-delay: 0.5s; }
.loading-letter:nth-child(6) { animation-delay: 0.6s; }

/* Main App */
.main-app {
    min-height: 100vh;
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition);
}

.main-app.show {
    opacity: 1;
    transform: translateY(0);
}

/* Header */
.header {
    background: var(--primary-gradient);
    padding: 60px 20px 30px;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="20" cy="20" r="1" fill="white" opacity="0.1"/><circle cx="80" cy="40" r="1" fill="white" opacity="0.1"/><circle cx="40" cy="80" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: relative;
    z-index: 1;
}

.back-btn {
    background: var(--bg-glass);
    border: none;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    color: var(--text-white);
    font-size: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: var(--transition);
    cursor: pointer;
}

.back-btn:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-neon);
}

.header-title {
    color: var(--text-white);
    font-size: 20px;
    font-weight: 600;
    text-align: center;
}

.ai-indicator {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-glass);
    padding: 8px 12px;
    border-radius: 20px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--text-white);
    font-size: 12px;
    font-weight: 500;
}

.ai-pulse {
    width: 8px;
    height: 8px;
    background: #00ff88;
    border-radius: 50%;
    animation: aiPulse 2s ease-in-out infinite;
}

/* User Welcome Section */
.user-welcome {
    padding: 20px;
    transform: translateY(-20px);
}

.welcome-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-large);
    padding: 24px;
    box-shadow: var(--shadow-medium);
    display: flex;
    align-items: center;
    gap: 20px;
    position: relative;
    overflow: hidden;
    transition: var(--transition);
}

.welcome-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--accent-gradient);
}

.welcome-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-large);
}

.user-avatar {
    width: 60px;
    height: 60px;
    background: var(--primary-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-white);
    font-size: 24px;
    flex-shrink: 0;
    box-shadow: var(--shadow-soft);
}

.user-info {
    flex: 1;
}

.user-name {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.account-details {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.account-type, .credits-info {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    color: var(--text-light);
}

.account-type i {
    color: #ffd700;
}

.credits-info i {
    color: var(--accent-color);
}

/* Recharge Section */
.recharge-section {
    padding: 0 20px 40px;
}

.section-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-dark);
}

.section-title i {
    color: var(--accent-color);
}

/* Amount Grid */
.amount-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-bottom: 20px;
}

.amount-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 20px 16px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition-bounce);
    position: relative;
    border: 2px solid transparent;
    box-shadow: var(--shadow-soft);
    overflow: hidden;
}

.amount-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(102, 126, 234, 0.1), transparent);
    transition: left 0.5s ease;
}

.amount-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-medium);
}

.amount-card:hover::before {
    left: 100%;
}

.amount-card.selected {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-neon);
    transform: translateY(-4px) scale(1.02);
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05), rgba(118, 75, 162, 0.05));
}

.amount-card.selected::after {
    content: '✓';
    position: absolute;
    top: 8px;
    right: 8px;
    width: 24px;
    height: 24px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    animation: checkmarkBounce 0.3s ease-out;
}

.amount-value {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.amount-label {
    font-size: 14px;
    font-weight: 600;
    color: var(--success-color);
    margin-bottom: 4px;
}

.amount-benefit {
    font-size: 12px;
    color: var(--text-light);
}

.popular-badge {
    position: absolute;
    top: -8px;
    right: -8px;
    background: var(--secondary-gradient);
    color: var(--text-white);
    font-size: 10px;
    font-weight: 600;
    padding: 4px 8px;
    border-radius: 12px;
    transform: rotate(12deg);
    box-shadow: var(--shadow-soft);
}

/* Custom Amount */
.custom-amount-section {
    margin-bottom: 20px;
}

.custom-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-dark);
}

.custom-title i {
    color: var(--secondary-color);
}

.custom-input-container {
    position: relative;
    margin-bottom: 8px;
}

.currency-symbol {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 18px;
    font-weight: 600;
    color: var(--text-light);
    z-index: 1;
}

.custom-input {
    width: 100%;
    padding: 16px 16px 16px 40px;
    border: 2px solid #e2e8f0;
    border-radius: var(--border-radius);
    font-size: 16px;
    font-weight: 500;
    background: var(--bg-secondary);
    transition: var(--transition);
    outline: none;
}

.custom-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.custom-benefit {
    text-align: center;
    font-size: 12px;
    color: var(--text-light);
    margin-top: 8px;
    font-style: italic;
}

.input-validation {
    margin-top: 8px;
    font-size: 12px;
    min-height: 16px;
}

.input-validation.error {
    color: var(--warning-color);
}

.input-validation.success {
    color: var(--success-color);
}

/* Selected Feedback - Immediate Visual Response */
.selected-feedback {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1), rgba(79, 172, 254, 0.1));
    border: 2px solid var(--primary-color);
    border-radius: var(--border-radius-large);
    padding: 20px;
    margin: 20px 0;
    animation: slideInBounce 0.4s ease-out;
    position: sticky;
    top: 20px;
    z-index: 10;
    backdrop-filter: blur(10px);
}

.feedback-content {
    display: flex;
    align-items: center;
    gap: 16px;
}

.feedback-icon {
    width: 50px;
    height: 50px;
    background: var(--success-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-dark);
    font-size: 24px;
    flex-shrink: 0;
    animation: pulse 2s infinite;
}

.feedback-text {
    flex: 1;
}

.feedback-amount {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.feedback-credits {
    font-size: 14px;
    color: var(--success-color);
    font-weight: 600;
}

.quick-recharge-btn {
    background: var(--primary-gradient);
    border: none;
    border-radius: var(--border-radius);
    padding: 12px 20px;
    color: var(--text-white);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: var(--shadow-soft);
}

.quick-recharge-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

/* Payment Summary */
.payment-summary {
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: var(--shadow-soft);
    border-left: 4px solid var(--accent-color);
    animation: fadeInUp 0.3s ease-out;
}

.summary-header h4 {
    margin: 0 0 16px 0;
    color: var(--text-dark);
    font-size: 16px;
    font-weight: 600;
}

.summary-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 12px;
    font-size: 14px;
    color: var(--text-light);
}

.summary-row.total {
    border-top: 1px solid #e2e8f0;
    padding-top: 12px;
    margin-top: 12px;
    font-weight: 600;
    color: var(--text-dark);
    font-size: 16px;
}

.summary-value {
    font-weight: 600;
    color: var(--primary-color);
}

.summary-row.total .summary-value {
    color: var(--success-color);
}

/* Recharge Button */
.recharge-btn {
    width: 100%;
    background: var(--primary-gradient);
    border: none;
    border-radius: var(--border-radius);
    padding: 18px;
    color: var(--text-white);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-medium);
    margin-bottom: 40px;
}

.recharge-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-large);
}

.recharge-btn:active {
    transform: translateY(0);
}

.recharge-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    background: linear-gradient(135deg, #a0aec0, #718096);
}

.recharge-btn:disabled:hover {
    transform: none;
    box-shadow: var(--shadow-medium);
}

.btn-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.btn-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.btn-spinner {
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top: 2px solid var(--text-white);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* Features Section */
.features-section {
    padding: 0 20px 40px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.feature-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 20px 16px;
    text-align: center;
    transition: var(--transition);
    box-shadow: var(--shadow-soft);
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.feature-icon {
    width: 50px;
    height: 50px;
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 12px;
    color: var(--text-white);
    font-size: 20px;
}

.feature-text h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 4px;
    color: var(--text-dark);
}

.feature-text p {
    font-size: 12px;
    color: var(--text-light);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(10px);
    opacity: 0;
    transition: var(--transition);
}

.modal.show {
    opacity: 1;
}

.modal-content {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-large);
    padding: 40px 30px;
    margin: 20px;
    max-width: 400px;
    width: 100%;
    text-align: center;
    transform: scale(0.8) translateY(20px);
    transition: var(--transition);
    box-shadow: var(--shadow-large);
}

.modal.show .modal-content {
    transform: scale(1) translateY(0);
}

/* Success Modal */
.success-animation {
    margin-bottom: 30px;
}

.success-checkmark {
    position: relative;
    width: 80px;
    height: 80px;
    margin: 0 auto;
}

.checkmark-circle {
    width: 80px;
    height: 80px;
    border: 4px solid var(--success-color);
    border-radius: 50%;
    position: relative;
    animation: checkmarkCircle 0.6s ease-in-out;
}

.checkmark-stem, .checkmark-kick {
    position: absolute;
    background: var(--success-color);
    border-radius: 2px;
}

.checkmark-stem {
    width: 4px;
    height: 20px;
    top: 35px;
    left: 38px;
    transform: rotate(45deg);
    animation: checkmarkStem 0.3s ease-in-out 0.3s both;
}

.checkmark-kick {
    width: 4px;
    height: 12px;
    top: 45px;
    left: 30px;
    transform: rotate(-45deg);
    animation: checkmarkKick 0.3s ease-in-out 0.6s both;
}

.success-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 12px;
}

.success-message {
    font-size: 16px;
    color: var(--text-light);
    margin-bottom: 24px;
    line-height: 1.5;
}

.success-details {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    padding: 20px;
    margin-bottom: 30px;
}

.success-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 14px;
}

.success-item:last-child {
    margin-bottom: 0;
    font-weight: 600;
    color: var(--text-dark);
}

.home-btn {
    width: 100%;
    background: var(--success-gradient);
    border: none;
    border-radius: var(--border-radius);
    padding: 16px;
    color: var(--text-dark);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.home-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

@keyframes checkmarkBounce {
    0% {
        transform: scale(0);
        opacity: 0;
    }
    50% {
        transform: scale(1.2);
        opacity: 1;
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes slideInBounce {
    0% {
        opacity: 0;
        transform: translateY(-20px) scale(0.9);
    }
    60% {
        opacity: 1;
        transform: translateY(5px) scale(1.02);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        opacity: 1;
    }
    50% {
        transform: scale(1.05);
        opacity: 0.8;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

@keyframes neuronPulse {
    0%, 100% {
        transform: scale(1);
        opacity: 1;
    }
    50% {
        transform: scale(1.2);
        opacity: 0.8;
    }
}

@keyframes connectionFlow {
    0%, 100% {
        opacity: 0.3;
    }
    50% {
        opacity: 0.8;
    }
}

@keyframes letterBounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

@keyframes aiPulse {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.5;
        transform: scale(0.8);
    }
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes checkmarkCircle {
    0% {
        transform: scale(0);
        opacity: 0;
    }
    50% {
        transform: scale(1.1);
        opacity: 1;
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes checkmarkStem {
    0% {
        height: 0;
        opacity: 0;
    }
    100% {
        height: 20px;
        opacity: 1;
    }
}

@keyframes checkmarkKick {
    0% {
        height: 0;
        opacity: 0;
    }
    100% {
        height: 12px;
        opacity: 1;
    }
}

/* Responsive Design */
@media (min-width: 480px) {
    .amount-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
    
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
}

@media (min-width: 768px) {
    .main-app {
        max-width: 480px;
        margin: 0 auto;
        box-shadow: var(--shadow-large);
    }
    
    .amount-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .amount-grid {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .features-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #1a202c;
        --bg-secondary: #2d3748;
        --text-dark: #f7fafc;
        --text-light: #a0aec0;
    }
}