/* Ratio Calculator - mobile-first */
.ratio-calc {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.ratio-calc__card {
    background: var(--card-bg, #fff);
    border-radius: 16px;
    padding: 1.5rem;
    border: 1px solid var(--border-color, #e5e7eb);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

@media (min-width: 768px) {
    .ratio-calc__card {
        padding: 2rem;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    }
}

.ratio-calc__input-row {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    grid-template-rows: auto auto;
    gap: 0.5rem 0.75rem;
    align-items: end;
    margin-bottom: 1.25rem;
}

.ratio-calc__label {
    grid-column: 1;
    grid-row: 1;
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--text-muted, #6b7280);
    letter-spacing: 0.02em;
}

.ratio-calc__label:last-of-type {
    grid-column: 3;
    grid-row: 1;
}

.ratio-calc__input {
    grid-column: 1;
    grid-row: 2;
    width: 100%;
    min-height: 48px;
    padding: 0.75rem 1rem;
    font-size: 1.125rem;
    font-weight: 600;
    text-align: center;
    border: 2px solid var(--border-color, #e5e7eb);
    border-radius: 10px;
    background: var(--card-bg, #fff);
    color: var(--text-color, #111827);
    transition: border-color 0.2s, box-shadow 0.2s;
    -webkit-appearance: none;
    appearance: none;
}

.ratio-calc__input::placeholder {
    color: var(--text-muted, #9ca3af);
    font-weight: 500;
}

.ratio-calc__input:focus {
    outline: none;
    border-color: var(--primary-color, #2563eb);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.ratio-calc__input:last-of-type {
    grid-column: 3;
    grid-row: 2;
}

.ratio-calc__colon {
    grid-column: 2;
    grid-row: 2;
    align-self: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-muted, #6b7280);
    line-height: 1;
    text-align: center;
}

.ratio-calc__btn {
    display: block;
    width: 100%;
    min-height: 48px;
    padding: 0.75rem 1.25rem;
    font-size: 1rem;
    font-weight: 600;
    color: #fff;
    background: var(--primary-color, #2563eb);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.ratio-calc__btn:hover {
    background: var(--primary-hover, #1d4ed8);
}

.ratio-calc__btn:active {
    transform: scale(0.98);
}

.ratio-calc__btn:focus-visible {
    outline: 2px solid var(--primary-color, #2563eb);
    outline-offset: 2px;
}

.ratio-calc__result {
    margin-top: 1.25rem;
    padding: 1rem 1.25rem;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    border-radius: 10px;
    border-left: 4px solid var(--primary-color, #2563eb);
    font-size: 1rem;
    line-height: 1.5;
}

.ratio-calc__result[hidden] {
    display: none;
}

.ratio-calc__result .ratio-calc__result-line {
    display: block;
    font-weight: 600;
    color: var(--text-color, #111827);
}

.ratio-calc__result .ratio-calc__result-gcd {
    display: block;
    margin-top: 0.25rem;
    font-size: 0.875rem;
    color: var(--text-muted, #6b7280);
}

.ratio-calc__result.ratio-calc__result--error {
    background: linear-gradient(135deg, #fef2f2 0%, #fee2e2 100%);
    border-left-color: #dc2626;
}

.ratio-calc__steps {
    margin-top: 1rem;
    padding: 1rem;
    background: var(--card-bg, #f9fafb);
    border-radius: 10px;
    font-size: 0.875rem;
    color: var(--text-muted, #6b7280);
}

.ratio-calc__steps[hidden] {
    display: none;
}

.ratio-calc__steps code {
    padding: 0.15em 0.4em;
    background: rgba(0, 0, 0, 0.06);
    border-radius: 4px;
    font-size: 0.9em;
}

/* About / educational block */
.ratio-calc__about {
    padding: 1.5rem;
    background: var(--card-bg, #f9fafb);
    border-radius: 12px;
    border: 1px solid var(--border-color, #e5e7eb);
}

.ratio-calc__about-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0 0 0.75rem;
    color: var(--text-color, #111827);
}

.ratio-calc__about p {
    margin: 0 0 0.75rem;
    font-size: 0.9375rem;
    line-height: 1.6;
    color: var(--text-muted, #4b5563);
}

.ratio-calc__about p:last-of-type {
    margin-bottom: 0.75rem;
}

.ratio-calc__about code {
    padding: 0.2em 0.45em;
    font-size: 0.875rem;
    background: rgba(0, 0, 0, 0.06);
    border-radius: 6px;
}

.ratio-calc__about ul {
    margin: 0;
    padding-left: 1.25rem;
    font-size: 0.9375rem;
    line-height: 1.6;
    color: var(--text-muted, #4b5563);
}

.ratio-calc__about li {
    margin-bottom: 0.25rem;
}

@media (min-width: 768px) {
    .ratio-calc__about {
        padding: 2rem;
    }

    .ratio-calc__about-title {
        font-size: 1.375rem;
    }
}