/* Books vs E-books Calculator - mobile-first */
.bvc-tool {
    margin-bottom: 2rem;
}

.bvc-presets {
    margin-bottom: 1.5rem;
}

.bvc-presets-label {
    display: block;
    font-size: 0.8125rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--text-muted, #64748b);
    margin-bottom: 0.5rem;
}

.bvc-preset-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.bvc-chip {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    
    color: var(--text-muted, #64748b);
    background: var(--bg-secondary, #f1f5f9);
    border: 1px solid transparent;
    border-radius: 9999px;
    cursor: pointer;
    transition: color 0.2s, background 0.2s, border-color 0.2s;
}

.bvc-chip:hover {
    color: var(--text-primary, #0f172a);
    background: var(--bg-tertiary, #e2e8f0);
}

.bvc-chip[aria-pressed="true"] {
    color: var(--primary-inverse, #fff);
    background: var(--primary, #0f172a);
    border-color: var(--primary, #0f172a);
}

.bvc-layout {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.bvc-inputs,
.bvc-results {
    background: var(--bg-card, #fff);
    border-radius: 12px;
    padding: 1.25rem;
    border: 1px solid var(--border-subtle, #e2e8f0);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.bvc-panel-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary, #0f172a);
    margin: 0 0 1rem 0;
    letter-spacing: -0.01em;
}

.bvc-field {
    margin-bottom: 1rem;
}

.bvc-field:last-of-type {
    margin-bottom: 1.25rem;
}

.bvc-field label {
    display: block;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--text-secondary, #334155);
    margin-bottom: 0.375rem;
}

.bvc-input {
    width: 100%;
    padding: 0.625rem 0.75rem;
    font-size: 1rem;
    color: var(--text-primary, #0f172a);
    background: var(--bg-input, #fff);
    border: 1px solid var(--border-default, #cbd5e1);
    border-radius: 8px;
    
    transition: border-color 0.2s, box-shadow 0.2s;
}

.bvc-input:hover {
    border-color: var(--border-hover, #94a3b8);
}

.bvc-input:focus {
    outline: none;
    border-color: var(--primary, #0f172a);
    box-shadow: 0 0 0 3px rgba(15, 23, 42, 0.12);
}

.bvc-hint {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted, #64748b);
    margin-top: 0.25rem;
}

.bvc-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.bvc-btn {
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
    font-weight: 600;
    
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.bvc-btn-primary {
    color: var(--primary-inverse, #fff);
    background: var(--primary, #0f172a);
    border: 1px solid var(--primary, #0f172a);
}

.bvc-btn-primary:hover {
    background: var(--primary-hover, #1e293b);
    border-color: var(--primary-hover, #1e293b);
}

.bvc-btn-secondary {
    color: var(--text-secondary, #475569);
    background: transparent;
    border: 1px solid var(--border-default, #cbd5e1);
}

.bvc-btn-secondary:hover {
    background: var(--bg-secondary, #f1f5f9);
    border-color: var(--border-hover, #94a3b8);
}

.bvc-results-placeholder {
    font-size: 0.9375rem;
    color: var(--text-muted, #64748b);
    margin: 0;
}

.bvc-results-output {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.bvc-stat-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.75rem;
}

.bvc-stat {
    padding: 0.875rem 1rem;
    background: var(--bg-secondary, #f8fafc);
    border-radius: 8px;
    border: 1px solid var(--border-subtle, #e2e8f0);
}

.bvc-stat-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--text-muted, #64748b);
    margin-bottom: 0.5rem;
}

.bvc-stat-row {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.bvc-stat-item {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--text-primary, #0f172a);
}

.bvc-stat-value {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--text-primary, #0f172a);
}

.bvc-stat-sublabel {
    display: block;
    font-size: 0.8125rem;
    color: var(--text-muted, #64748b);
    margin-top: 0.25rem;
}

.bvc-stat-diff {
    font-size: 0.8125rem;
    margin-top: 0.5rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--border-subtle, #e2e8f0);
}

.bvc-stat-diff.savings {
    color: var(--success, #15803d);
    font-weight: 500;
}

.bvc-stat-diff.extra {
    color: var(--warning, #b45309);
    font-weight: 500;
}

.bvc-recommendation {
    padding: 0.875rem 1rem;
    font-size: 0.9375rem;
    line-height: 1.5;
    border-radius: 8px;
    border-left: 4px solid var(--primary, #0f172a);
    background: var(--bg-secondary, #f8fafc);
}

.bvc-recommendation strong {
    display: block;
    margin-bottom: 0.25rem;
}

.bvc-tip {
    font-size: 0.8125rem;
    color: var(--text-muted, #64748b);
    padding: 0.5rem 0;
}

.bvc-tip:empty {
    display: none;
}

/* Tablet and up: side-by-side layout */
@media (min-width: 640px) {
    .bvc-stat-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 900px) {
    .bvc-layout {
        flex-direction: row;
        align-items: flex-start;
        gap: 1.5rem;
    }

    .bvc-inputs {
        flex: 0 0 320px;
        position: sticky;
        top: 1rem;
    }

    .bvc-results {
        flex: 1;
        min-width: 0;
    }

    .bvc-stat-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1100px) {
    .bvc-stat-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Education section */
.bvc-edu {
    margin-top: 2rem;
    margin-bottom: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-subtle, #e2e8f0);
}

.bvc-edu-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary, #0f172a);
    margin: 0 0 1.25rem 0;
}

.bvc-edu-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

.bvc-edu-block {
    padding: 1.25rem;
    background: var(--bg-secondary, #f8fafc);
    border-radius: 10px;
    border: 1px solid var(--border-subtle, #e2e8f0);
}

.bvc-edu-block h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary, #0f172a);
    margin: 0 0 0.5rem 0;
}

.bvc-edu-block h4 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary, #334155);
    margin: 0.75rem 0 0.375rem 0;
}

.bvc-edu-block p {
    font-size: 0.9375rem;
    line-height: 1.55;
    color: var(--text-secondary, #475569);
    margin: 0 0 0.5rem 0;
}

.bvc-edu-block ul {
    margin: 0.25rem 0 0 0;
    padding-left: 1.25rem;
}

.bvc-edu-block li {
    font-size: 0.875rem;
    line-height: 1.5;
    color: var(--text-secondary, #475569);
    margin-bottom: 0.25rem;
}

@media (min-width: 768px) {
    .bvc-edu-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .bvc-edu-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}