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

:root {
    --primary-black: #0a0a0f;
    --primary-darker: #0d0d14;
    --accent-cyan: #22d3ee;
    --accent-magenta: #cd74d9;
    --accent-pink: #ff5fba;
    --accent-blue: #3b82f6;
    --text-primary: #e0e0e0;
    --text-secondary: #888;
    --text-muted: #666;
    --border-color: rgba(34, 211, 238, 0.2);
    --card-bg: rgba(255, 255, 255, 0.03);
    --success-bg: rgba(34, 211, 238, 0.15);
    --success-border: var(--accent-cyan);
    --error-bg: rgba(244, 67, 54, 0.15);
    --error-border: #f44336;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: linear-gradient(135deg, var(--primary-black) 0%, var(--primary-darker) 50%, #0f1420 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

.gradient-text {
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta), var(--accent-pink));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 30px 20px;
    position: relative;
}

header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 150px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-magenta), var(--accent-pink));
    border-radius: 3px;
}

header h1 {
    font-size: 2.8rem;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta), var(--accent-pink));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 12px;
    font-weight: 700;
}

header .subtitle {
    color: var(--text-secondary);
    font-size: 1.15rem;
}

/* SEO Section */
.seo-intro {
    background: linear-gradient(135deg, rgba(34, 211, 238, 0.05), rgba(205, 116, 217, 0.05));
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 24px;
    margin-bottom: 30px;
}

.seo-intro h2 {
    font-size: 1.3rem;
    color: var(--accent-cyan);
    margin-bottom: 12px;
}

.seo-intro p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 10px;
}

.seo-intro ul {
    margin: 15px 0 0 20px;
}

.seo-intro li {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 6px;
}

.seo-intro li::marker {
    color: var(--accent-magenta);
}

.card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 24px;
    margin-bottom: 24px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.card.disabled {
    opacity: 0.4;
    pointer-events: none;
}

.card.active {
    border-color: var(--accent-cyan);
    box-shadow: 0 0 30px rgba(34, 211, 238, 0.15);
}

.step-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 24px;
}

.step-number {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.1rem;
    color: var(--primary-black);
    flex-shrink: 0;
}

.step-header h2 {
    font-size: 1.4rem;
    flex-grow: 1;
    color: #fff;
}

.header-actions {
    display: flex;
    gap: 10px;
}

.step-content p {
    margin-bottom: 15px;
    color: var(--text-secondary);
}

textarea, input[type="text"], input[type="date"] {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 12px;
    background: rgba(0, 0, 0, 0.3);
    color: #fff;
    font-size: 0.95rem;
    font-family: 'Monaco', 'Menlo', monospace;
    transition: all 0.2s ease;
}

textarea {
    resize: vertical;
    min-height: 100px;
}

textarea:focus, input:focus {
    outline: none;
    border-color: var(--accent-cyan);
    box-shadow: 0 0 20px rgba(34, 211, 238, 0.1);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin-bottom: 16px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.button-group {
    display: flex;
    gap: 12px;
    margin-top: 18px;
}

.btn {
    padding: 14px 28px;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta));
    color: var(--primary-black);
    box-shadow: 0 4px 20px rgba(34, 211, 238, 0.3);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 30px rgba(34, 211, 238, 0.4);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.08);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-secondary:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.15);
    border-color: var(--accent-cyan);
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.85rem;
    border-radius: 8px;
}

.link-btn {
    color: var(--accent-cyan);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s ease;
}

.link-btn:hover {
    color: var(--accent-magenta);
    text-decoration: underline;
}

.token-actions {
    margin-bottom: 16px;
    padding: 12px 16px;
    background: rgba(34, 211, 238, 0.05);
    border: 1px dashed var(--border-color);
    border-radius: 10px;
}

.result {
    margin-top: 18px;
    padding: 16px 20px;
    border-radius: 12px;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.result.success {
    background: var(--success-bg);
    border: 1px solid var(--success-border);
    color: var(--accent-cyan);
}

.result.success::before {
    content: '✓';
    font-weight: bold;
}

.result.error {
    background: var(--error-bg);
    border: 1px solid var(--error-border);
    color: #e57373;
}

.result.error::before {
    content: '✕';
    font-weight: bold;
}

.hidden {
    display: none !important;
}

/* Table */
#invoices-table-container {
    overflow-x: auto;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.08);
}

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 14px 16px;
    text-align: left;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

th {
    background: rgba(0, 0, 0, 0.3);
    font-weight: 600;
    color: var(--accent-cyan);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

tr:hover {
    background: rgba(34, 211, 238, 0.03);
}

td input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--accent-cyan);
}

.empty-state {
    text-align: center;
    padding: 50px;
    color: var(--text-muted);
}

.empty-state p {
    font-size: 1.1rem;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.85);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal-content {
    background: linear-gradient(135deg, var(--primary-darker), var(--primary-black));
    border-radius: 20px;
    max-width: 950px;
    width: 92%;
    max-height: 90vh;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    box-shadow: 0 25px 80px rgba(0, 0, 0, 0.5);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    position: sticky;
    top: 0;
    background: var(--primary-darker);
    z-index: 10;
}

.modal-header h3 {
    font-size: 1.5rem;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.modal-close {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 2rem;
    cursor: pointer;
    transition: color 0.2s ease;
    line-height: 1;
}

.modal-close:hover {
    color: var(--accent-pink);
}

.modal-body {
    padding: 24px;
}

.modal-footer {
    display: flex;
    gap: 12px;
    padding: 20px 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    justify-content: flex-end;
    flex-wrap: wrap;
}

/* Invoice Details */
.invoice-section {
    margin-bottom: 28px;
}

.invoice-section h4 {
    color: var(--accent-magenta);
    margin-bottom: 14px;
    font-size: 1.1rem;
    font-weight: 600;
}

.invoice-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.invoice-box {
    background: rgba(0, 0, 0, 0.25);
    padding: 18px;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.invoice-box h5 {
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 600;
}

.invoice-box p {
    margin-bottom: 6px;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.invoice-box .amount {
    font-size: 1.5rem;
    font-weight: bold;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-top: 8px;
}

.items-table {
    width: 100%;
    margin-top: 12px;
}

.items-table th {
    background: rgba(0, 0, 0, 0.4);
    font-size: 0.8rem;
    padding: 10px 12px;
}

.items-table td {
    font-size: 0.9rem;
    padding: 10px 12px;
}

/* Loading */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    backdrop-filter: blur(8px);
}

.spinner {
    width: 56px;
    height: 56px;
    border: 4px solid rgba(255, 255, 255, 0.1);
    border-top-color: var(--accent-cyan);
    border-right-color: var(--accent-magenta);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

#loading-text {
    margin-top: 18px;
    font-size: 1.1rem;
    color: var(--accent-cyan);
    font-weight: 500;
}

/* Footer */
footer {
    text-align: center;
    padding: 30px 20px;
    color: var(--text-muted);
    font-size: 0.9rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    margin-top: 40px;
}

footer a {
    color: var(--accent-cyan);
    text-decoration: none;
    transition: color 0.2s ease;
}

footer a:hover {
    color: var(--accent-magenta);
}

/* Instructions */
.instructions {
    background: linear-gradient(135deg, rgba(205, 116, 217, 0.05), rgba(255, 95, 186, 0.05));
    border: 1px solid rgba(205, 116, 217, 0.2);
    border-radius: 16px;
    padding: 24px;
    margin-bottom: 30px;
}

.instructions h2 {
    color: var(--accent-magenta);
    font-size: 1.2rem;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.instructions ol {
    margin-left: 24px;
}

.instructions li {
    color: var(--text-secondary);
    margin-bottom: 10px;
    font-size: 0.95rem;
    line-height: 1.6;
}

.instructions li strong {
    color: var(--accent-cyan);
}

.instructions code {
    background: rgba(0, 0, 0, 0.3);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: monospace;
    font-size: 0.9em;
    color: var(--accent-pink);
}

/* Alert box */
.alert {
    padding: 16px 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    font-size: 0.95rem;
}

.alert-info {
    background: rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.3);
    color: #93c5fd;
}

.alert-warning {
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.3);
    color: #fcd34d;
}

/* Responsive */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .invoice-grid {
        grid-template-columns: 1fr;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .modal-content {
        width: 96%;
        margin: 10px;
    }

    .btn {
        padding: 12px 20px;
        font-size: 0.95rem;
    }

    .step-header {
        flex-wrap: wrap;
    }

    .header-actions {
        width: 100%;
        margin-top: 12px;
    }

    .modal-footer {
        flex-direction: column;
    }

    .modal-footer .btn {
        width: 100%;
    }
}

/* Focus visible for accessibility */
:focus-visible {
    outline: 2px solid var(--accent-cyan);
    outline-offset: 2px;
}

/* Selection */
::selection {
    background: rgba(34, 211, 238, 0.3);
    color: #fff;
}