/* Unknown selector */
.unknown-selector {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.unknown-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.25rem;
    padding: 0.75rem 0.5rem;
    border: 2px solid var(--border, #e2e8f0);
    border-radius: 10px;
    background: transparent;
    cursor: pointer;
    transition: all 0.18s;
    font-family: 'Montserrat', sans-serif;
}

.unknown-btn .unk-symbol {
    font-size: 1.3rem;
    font-weight: 700;
    font-family: 'Ubuntu', monospace, sans-serif;
    color: var(--text, #1e293b);
}

.unknown-btn .unk-label {
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-muted, #64748b);
    text-align: center;
    line-height: 1.2;
}

.unknown-btn:hover {
    border-color: var(--primary, #2563eb);
    background: rgba(37, 99, 235, 0.05);
}

.unknown-btn.active {
    border-color: var(--primary, #2563eb);
    background: var(--primary, #2563eb);
}

.unknown-btn.active .unk-symbol,
.unknown-btn.active .unk-label {
    color: #fff;
}

/* Input fields */
.fields-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1.25rem;
}

.field-group {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.field-group label {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted, #64748b);
    font-family: 'Montserrat', sans-serif;
}

.field-group label .field-sym {
    font-family: 'Ubuntu', monospace, sans-serif;
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--primary, #2563eb);
}

.field-input-wrap {
    display: flex;
    border: 2px solid var(--border, #e2e8f0);
    border-radius: 8px;
    overflow: hidden;
    background: var(--bg-input, #f8fafc);
    transition: border-color 0.18s, box-shadow 0.18s;
}

.field-input-wrap:focus-within {
    border-color: var(--primary, #2563eb);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
    background: #fff;
}

.field-input-wrap.field-disabled {
    background: var(--bg-alt, #f1f5f9);
    border-color: var(--border, #e2e8f0);
    opacity: 0.55;
    pointer-events: none;
}

.field-input-wrap input {
    flex: 1;
    border: none;
    padding: 0.6rem 0.75rem;
    font-size: 0.95rem;
    font-family: 'Montserrat', sans-serif;
    font-weight: 600;
    color: var(--text, #1e293b);
    background: transparent;
    min-width: 0;
}

.field-input-wrap input:focus {
    outline: none;
}

.field-input-wrap select {
    border: none;
    border-left: 1px solid var(--border, #e2e8f0);
    padding: 0.6rem 0.5rem;
    font-size: 0.78rem;
    font-weight: 600;
    font-family: 'Montserrat', sans-serif;
    color: var(--text-muted, #64748b);
    background: var(--bg-alt, #f1f5f9);
    cursor: pointer;
    min-width: 0;
    max-width: 90px;
}

.field-input-wrap select:focus {
    outline: none;
}

/* Visual Equation */
.equation-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem 1.5rem;
    background: var(--bg-alt, #f8fafc);
    border: 1px solid var(--border, #e2e8f0);
    border-radius: 12px;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.eq-var {
    font-family: 'Ubuntu', monospace, sans-serif;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-muted, #94a3b8);
    transition: color 0.2s, transform 0.2s;
}

.eq-var.eq-highlight {
    color: var(--primary, #2563eb);
    transform: scale(1.15);
}

.eq-var.eq-unknown {
    color: #ef4444;
    transform: scale(1.2);
}

.eq-op {
    font-size: 1.2rem;
    color: var(--text-muted, #94a3b8);
    font-weight: 400;
}

/* Results */
.result-hero {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    padding: 1.25rem 1.5rem;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.08) 0%, rgba(99, 102, 241, 0.06) 100%);
    border: 2px solid var(--primary, #2563eb);
    border-radius: 14px;
    margin-bottom: 1.25rem;
}

.result-hero-icon {
    width: 52px;
    height: 52px;
    border-radius: 12px;
    background: var(--primary, #2563eb);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    font-family: 'Ubuntu', monospace, sans-serif;
    font-weight: 700;
    flex-shrink: 0;
}

.result-hero-text .result-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted, #64748b);
    font-family: 'Montserrat', sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.result-hero-text .result-value {
    font-size: 1.75rem;
    font-weight: 700;
    font-family: 'Ubuntu', monospace, sans-serif;
    color: var(--primary, #2563eb);
    line-height: 1.2;
}

.result-hero-text .result-name {
    font-size: 0.85rem;
    color: var(--text-muted, #64748b);
    font-family: 'Montserrat', sans-serif;
}

/* Calc steps */
.steps-section {
    margin-top: 1.25rem;
}

.steps-section h3 {
    font-size: 1rem;
    font-weight: 700;
    font-family: 'Montserrat', sans-serif;
    color: var(--text, #1e293b);
    margin-bottom: 0.75rem;
}

.steps-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.step-item {
    display: flex;
    gap: 0.85rem;
    align-items: flex-start;
    padding: 0.75rem 1rem;
    background: var(--bg-alt, #f8fafc);
    border-radius: 10px;
    border-left: 3px solid var(--primary, #2563eb);
}

.step-num {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--primary, #2563eb);
    color: #fff;
    font-size: 0.75rem;
    font-weight: 700;
    font-family: 'Montserrat', sans-serif;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    margin-top: 1px;
}

.step-text {
    font-size: 0.875rem;
    color: var(--text, #1e293b);
    font-family: 'Montserrat', sans-serif;
    line-height: 1.5;
}

.step-text code {
    font-family: 'Ubuntu', monospace, sans-serif;
    font-size: 0.9rem;
    font-weight: 700;
    background: rgba(37, 99, 235, 0.08);
    padding: 0.1em 0.4em;
    border-radius: 4px;
    color: var(--primary, #2563eb);
}

/* Other calculated variables */
.other-vars {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.65rem;
    margin-top: 1rem;
}

.other-var-card {
    padding: 0.75rem;
    background: #fff;
    border: 1px solid var(--border, #e2e8f0);
    border-radius: 10px;
    text-align: center;
}

.other-var-card .ov-sym {
    font-family: 'Ubuntu', monospace, sans-serif;
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary, #2563eb);
}

.other-var-card .ov-val {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--text, #1e293b);
    font-family: 'Montserrat', sans-serif;
    display: block;
    margin-top: 0.15rem;
}

.other-var-card .ov-unit {
    font-size: 0.72rem;
    color: var(--text-muted, #64748b);
    font-family: 'Montserrat', sans-serif;
}

/* R constant table */
.r-table-wrap {
    overflow-x: auto;
    border-radius: 10px;
    border: 1px solid var(--border, #e2e8f0);
    margin-top: 0.75rem;
}

.r-table-wrap table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.r-table-wrap thead {
    background: var(--primary, #2563eb);
    color: #fff;
}

.r-table-wrap thead th {
    padding: 0.6rem 1rem;
    text-align: left;
    font-weight: 600;
    font-family: 'Montserrat', sans-serif;
    white-space: nowrap;
}

.r-table-wrap tbody tr:nth-child(even) {
    background: var(--bg-alt, #f8fafc);
}

.r-table-wrap tbody td {
    padding: 0.55rem 1rem;
    color: var(--text, #1e293b);
    border-bottom: 1px solid var(--border, #e2e8f0);
    font-family: 'Montserrat', sans-serif;
}

.r-table-wrap tbody tr:last-child td {
    border-bottom: none;
}

.r-highlight {
    font-weight: 700;
    color: var(--primary, #2563eb);
}

/* Error Styles */
.parse-error {
    display: flex;
    justify-self: center;
    margin-bottom: 1rem;
    padding: 12px;
    color: red;
    border-radius: 8px;
    border: solid;
    border-width: 1px;
}

/* Responsive */
@media (max-width: 600px) {
    .unknown-selector {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .other-vars {
        grid-template-columns: repeat(3, 1fr);
    }

    .result-hero-text .result-value {
        font-size: 1.4rem;
    }
}