:root {
    --primary: #00c9a7;
    --primary-dark: #00a58a;
    --primary-light: #ccf5ed;
    --secondary: #00b4d8;
    --accent: #7c3aed;
    --bg: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
    --card-bg: rgba(30, 41, 59, 0.8);
    --card-border: rgba(255, 255, 255, 0.1);
    --text: #f1f5f9;
    --text-muted: #94a3b8;
    --text-light: #64748b;
    --success: #10b981;
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    --glow: 0 0 40px rgba(0, 201, 167, 0.2);
    --radius: 20px;
    --radius-sm: 12px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    min-height: 100vh;
    color: var(--text);
}

.app {
    max-width: 480px;
    margin: 0 auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    padding: 20px;
}

/* Header */
.header {
    text-align: center;
    padding: 32px 0;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 8px;
}

.logo-icon {
    font-size: 40px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-8px);
    }
}

.header h1 {
    font-size: 28px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-muted);
    font-size: 15px;
    font-weight: 400;
}

/* Content */
.content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

/* Step System */
.step {
    display: none;
    flex-direction: column;
    gap: 24px;
    animation: fadeIn 0.4s ease forwards;
}

.step.active {
    display: flex;
}

/* Amount Section */
.amount-section {
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--card-border);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow), var(--glow);
}

.amount-section>label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.amount-input-wrapper {
    display: flex;
    align-items: center;
    background: rgba(0, 0, 0, 0.3);
    border: 2px solid var(--card-border);
    border-radius: var(--radius-sm);
    padding: 4px 16px;
    transition: all 0.3s ease;
}

.amount-input-wrapper:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(0, 201, 167, 0.15);
}

.amount-input-wrapper.shake {
    animation: shake 0.5s ease;
    border-color: #ef4444;
}

@keyframes shake {

    0%,
    100% {
        transform: translateX(0);
    }

    20%,
    60% {
        transform: translateX(-8px);
    }

    40%,
    80% {
        transform: translateX(8px);
    }
}

.currency {
    font-size: 32px;
    font-weight: 600;
    color: var(--primary);
    margin-right: 8px;
}

.amount-input-wrapper input {
    flex: 1;
    border: none;
    background: transparent;
    font-family: inherit;
    font-size: 48px;
    font-weight: 700;
    color: var(--text);
    padding: 12px 0;
    outline: none;
    width: 100%;
    min-width: 0;
}

.amount-input-wrapper input::placeholder {
    color: var(--text-light);
}

/* Quick Amounts */
.quick-amounts {
    display: flex;
    gap: 8px;
    margin-top: 16px;
    flex-wrap: wrap;
}

.quick-btn {
    flex: 1;
    min-width: 60px;
    padding: 10px 12px;
    border: 1px solid var(--card-border);
    background: rgba(0, 0, 0, 0.2);
    color: var(--text-muted);
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s ease;
}

.quick-btn:hover {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 201, 167, 0.3);
}

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

/* Reference Input */
.reference-group {
    margin-top: 20px;
}

.reference-group label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.reference-group input {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--card-border);
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 15px;
    color: var(--text);
    outline: none;
    transition: all 0.3s ease;
}

.reference-group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(0, 201, 167, 0.15);
}

.reference-group input::placeholder {
    color: var(--text-light);
}

/* Next Button */
.next-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    padding: 18px 24px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border: none;
    border-radius: var(--radius);
    color: white;
    font-family: inherit;
    font-size: 17px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px rgba(0, 201, 167, 0.4);
}

.next-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 201, 167, 0.5);
}

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

.next-btn svg {
    transition: transform 0.3s ease;
}

.next-btn:hover svg {
    transform: translateX(4px);
}

/* Back Button */
.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-sm);
    color: var(--text-muted);
    font-family: inherit;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    align-self: flex-start;
}

.back-btn:hover {
    color: var(--text);
    border-color: var(--text-muted);
    background: rgba(255, 255, 255, 0.1);
}

.back-btn svg {
    transition: transform 0.2s ease;
}

.back-btn:hover svg {
    transform: translateX(-4px);
}

/* Amount Summary */
.amount-summary {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 24px;
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--card-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.summary-label {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.summary-amount {
    font-size: 42px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.summary-reference {
    font-size: 14px;
    color: var(--text-muted);
    padding: 6px 14px;
    background: rgba(0, 201, 167, 0.1);
    border-radius: 20px;
    margin-top: 4px;
}

/* Payment Methods */
.payment-methods {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.payment-methods h2 {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Method Cards */
.method-card {
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--card-border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    text-decoration: none;
    color: inherit;
    display: block;
}

.method-card:hover {
    transform: translateY(-2px);
    border-color: var(--primary);
    box-shadow: var(--shadow), var(--glow);
}

.method-header {
    display: flex;
    align-items: center;
    gap: 16px;
}

.method-icon {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    box-shadow: 0 4px 12px rgba(0, 201, 167, 0.3);
}

.method-icon.paypal-icon {
    background: linear-gradient(135deg, #003087 0%, #009cde 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(0, 156, 222, 0.3);
}

.method-info {
    flex: 1;
}

.method-info h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 2px;
}

.method-info p {
    font-size: 14px;
    color: var(--text-muted);
}

.arrow-icon {
    font-size: 24px;
    color: var(--text-muted);
    transition: all 0.3s ease;
}

.method-card.paypal:hover .arrow-icon {
    color: var(--text);
    transform: translateX(4px);
}

/* QR Code Container */
.qr-container {
    margin: 24px 0;
    text-align: center;
}

#qr-code {
    display: inline-flex;
    padding: 16px;
    background: white;
    border-radius: 16px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

#qr-code img {
    display: block;
    max-width: 100%;
    height: auto;
}

#qr-code canvas {
    display: none;
}

.qr-hint {
    display: block;
    margin-top: 12px;
    font-size: 13px;
    color: var(--text-muted);
}

/* IBAN Container */
.iban-container {
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-sm);
    padding: 16px;
}

.iban-row {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 0;
}

.iban-row:first-child {
    border-bottom: 1px solid var(--card-border);
    padding-bottom: 12px;
    margin-bottom: 4px;
}

.iban-label {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    min-width: 70px;
}

.iban-value {
    flex: 1;
    font-size: 14px;
    font-weight: 500;
    color: var(--text);
    font-family: 'SF Mono', Monaco, 'Courier New', monospace;
    letter-spacing: 0.5px;
}

.copy-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    border: 1px solid var(--primary);
    background: rgba(0, 201, 167, 0.1);
    color: var(--primary);
    font-family: inherit;
    font-size: 13px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.copy-btn:hover {
    background: var(--primary);
    color: white;
}

.copy-btn.copied {
    background: var(--success);
    border-color: var(--success);
    color: white;
}

/* Footer */
.footer {
    padding: 24px 0;
    text-align: center;
}

.footer p {
    font-size: 14px;
    color: var(--text-light);
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.amount-section,
.method-card {
    animation: fadeIn 0.5s ease forwards;
}

.method-card:nth-child(2) {
    animation-delay: 0.1s;
}

.method-card:nth-child(3) {
    animation-delay: 0.2s;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    padding: 14px 24px;
    background: var(--success);
    color: white;
    font-weight: 600;
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(16, 185, 129, 0.4);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

/* Responsive */
@media (max-width: 400px) {
    .app {
        padding: 16px;
    }

    .amount-input-wrapper input {
        font-size: 36px;
    }

    .currency {
        font-size: 24px;
    }

    .quick-btn {
        min-width: 50px;
        padding: 10px 8px;
    }

    .summary-amount {
        font-size: 32px;
    }
}