:root {
    --bg: #0a0a0f;
    --surface: #141420;
    --border: #1e1e30;
    --text: #e0e0e8;
    --text-muted: #8888a0;
    --accent: #f7931a;
    --accent-glow: rgba(247, 147, 26, 0.15);
    --success: #00c853;
    --error: #ff5252;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 2rem 1rem;
}

.container {
    max-width: 480px;
    width: 100%;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.5rem;
    letter-spacing: 0.1em;
    color: var(--accent);
}

.subtitle {
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* Steps */
.step {
    display: none;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.step.active {
    display: block;
}

.step h2 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text);
}

.instruction {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

/* Tier buttons */
.tiers {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.tier-btn {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s;
}

.tier-btn:hover {
    border-color: var(--accent);
    background: var(--accent-glow);
}

.tier-amount {
    font-weight: 600;
    font-size: 1.1rem;
}

.tier-price {
    color: var(--accent);
    font-weight: 500;
}

/* QR code */
#qr-container {
    display: flex;
    justify-content: center;
    margin: 1rem 0;
    padding: 1rem;
    background: #fff;
    border-radius: 8px;
    width: fit-content;
    margin-left: auto;
    margin-right: auto;
}

/* Invoice */
.invoice-row {
    display: flex;
    gap: 0.5rem;
    margin: 1rem 0;
}

.invoice-row code {
    flex: 1;
    padding: 0.5rem;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 0.7rem;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: var(--text-muted);
}

#copy-btn {
    padding: 0.5rem 1rem;
    background: var(--border);
    border: none;
    border-radius: 6px;
    color: var(--text);
    cursor: pointer;
    font-size: 0.8rem;
}

#copy-btn:hover {
    background: var(--accent);
    color: #000;
}

/* Status */
.status {
    text-align: center;
    padding: 0.75rem;
    border-radius: 6px;
    font-size: 0.9rem;
    color: var(--accent);
}

.status.paid {
    color: var(--success);
    background: rgba(0, 200, 83, 0.1);
}

.timer {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 0.5rem;
}

/* Primary button */
.primary-btn {
    display: block;
    width: 100%;
    padding: 1rem;
    background: var(--accent);
    color: #000;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s;
    margin-top: 1rem;
}

.primary-btn:hover {
    opacity: 0.9;
}

/* Node info */
#node-info {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 1rem;
    font-size: 0.85rem;
    line-height: 1.6;
}

#node-info .label {
    color: var(--text-muted);
}

#node-info .value {
    color: var(--success);
    font-family: monospace;
}

/* Help section */
.help {
    margin-top: 1rem;
}

.help details {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.help summary {
    cursor: pointer;
    color: var(--accent);
}

.help ol {
    margin-top: 0.5rem;
    padding-left: 1.25rem;
}

.help li {
    margin-bottom: 0.25rem;
}

.help a {
    color: var(--accent);
}

/* Footer */
footer {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 1rem;
}

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

.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    vertical-align: middle;
    margin-right: 0.5rem;
}