:root {
    --sp-primary: #2563eb;
    --sp-bg: #f8fafc;
    --sp-card: #ffffff;
    --sp-text: #1e293b;
    --sp-border: #e2e8f0;
    --sp-radius: 14px;
    --sp-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

.sp-container {
    max-width: 600px;
    margin: 2rem auto;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    color: var(--sp-text);
    background: var(--sp-bg);
    min-height: 80vh;
    border-radius: var(--sp-radius);
    overflow: hidden;
}

.sp-card {
    background: var(--sp-card);
    border-radius: var(--sp-radius);
    padding: 1.5rem;
    margin-bottom: 1rem;
    box-shadow: var(--sp-shadow);
    border: 1px solid var(--sp-border);
    transition: transform 0.2s ease;
}

/* Realistic Strings Visual */
.sp-string-visual {
    background: #1a1a1a;
    height: 80px;
    border-radius: 8px;
    margin: 1rem 0;
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    padding: 10px 0;
    overflow: hidden;
    position: relative;
}

.sp-string {
    height: 2px;
    width: 100%;
    background: linear-gradient(180deg, #999 0%, #fff 50%, #666 100%);
    box-shadow: 0 1px 2px rgba(0,0,0,0.5);
}

.sp-string.wound {
    background: repeating-linear-gradient(90deg, #888, #888 1px, #aaa 2px, #888 3px);
}

/* UI Components */
.sp-btn-buy {
    background: var(--sp-primary);
    color: white;
    font-weight: 700;
    padding: 12px;
    text-align: center;
    border-radius: 10px;
    display: block;
    text-decoration: none;
    margin-top: 10px;
}

.sp-sync-banner {
    background: #eff6ff;
    padding: 12px;
    text-align: center;
    font-size: 0.9rem;
    border-bottom: 1px solid var(--sp-border);
}