.subnet-page {
    --subnet-bg: #f5f6f8;
    --subnet-card: #ffffff;
    --subnet-text: #172033;
    --subnet-muted: #687386;
    --subnet-border: #d9dee8;
    --subnet-primary: #2457d6;
    --subnet-primary-dark: #1d46ad;

    width: min(1140px, 100%);
    margin: 0 auto;
    padding: 2rem 0 3rem;
    color: var(--subnet-text);
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.subnet-page *,
.subnet-page *::before,
.subnet-page *::after {
    box-sizing: border-box;
}

.subnet-heading {
    margin-bottom: 1.5rem;
}

.subnet-heading h1,
.subnet-results-heading h2,
.subnet-controls h2 {
    margin: 0;
    font-weight: 800;
    letter-spacing: -0.025em;
}

.subnet-heading h1 {
    font-size: clamp(2rem, 5vw, 3rem);
}

.subnet-heading > p:last-child {
    max-width: 640px;
    margin: 0.5rem 0 0;
    color: var(--subnet-muted);
    font-size: 1.05rem;
}

.subnet-eyebrow {
    margin: 0 0 0.35rem;
    color: var(--subnet-primary);
    font-size: 0.75rem;
    font-weight: 800;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.subnet-card {
    padding: 1.25rem;
    background: var(--subnet-card);
    border: 1px solid var(--subnet-border);
    border-radius: 18px;
    box-shadow: 0 8px 24px rgba(23, 32, 51, 0.06);
}

.subnet-workspace {
    display: grid;
    gap: 2rem;
}

.subnet-controls h2 {
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.subnet-input-row {
    display: grid;
    gap: 0.75rem;
}

.subnet-input-row label {
    display: grid;
    gap: 0.4rem;
    color: var(--subnet-text);
    font-weight: 700;
}

.subnet-input-row input {
    width: 100%;
    min-height: 48px;
    padding: 0.75rem 0.9rem;
    color: var(--subnet-text);
    font: 1rem/1.4 "Source Code Pro", Consolas, monospace;
    background: #fff;
    border: 1px solid var(--subnet-border);
    border-radius: 12px;
    outline: none;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.subnet-input-row input:focus {
    border-color: var(--subnet-primary);
    box-shadow: 0 0 0 0.2rem rgba(36, 87, 214, 0.14);
}

.subnet-input-row input.is-invalid {
    border-color: #b42318;
}

.subnet-calculate {
    min-height: 48px;
    padding: 0.75rem 1.25rem;
    color: #fff;
    font-weight: 800;
    background: var(--subnet-primary);
    border: 0;
    border-radius: 12px;
    cursor: pointer;
    transition: background 0.15s ease, transform 0.15s ease;
}

.subnet-calculate:hover,
.subnet-calculate:focus-visible {
    background: var(--subnet-primary-dark);
}

.subnet-calculate:active {
    transform: translateY(1px);
}

.subnet-alert {
    position: relative;
    margin-top: 0.75rem;
    padding: 0.85rem 2.75rem 0.85rem 0.9rem;
    color: #842029;
    background: #fdecec;
    border: 1px solid #f2b8b5;
    border-radius: 12px;
}

.subnet-alert-close {
    position: absolute;
    top: 50%;
    right: 0.75rem;
    padding: 0;
    color: inherit;
    font-size: 1.5rem;
    line-height: 1;
    background: transparent;
    border: 0;
    cursor: pointer;
    transform: translateY(-50%);
}

.subnet-prefixes {
    margin: 1.25rem 0 0;
    padding: 0;
    border: 0;
}

.subnet-prefixes legend {
    margin-bottom: 0.55rem;
    color: var(--subnet-text);
    font-size: 0.9rem;
    font-weight: 800;
}

.subnet-prefix-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(52px, 1fr));
    gap: 0.45rem;
}

.subnet-prefix-grid button {
    min-height: 40px;
    padding: 0.45rem;
    color: var(--subnet-primary);
    font: 700 0.9rem/1 "Source Code Pro", Consolas, monospace;
    background: #f4f7ff;
    border: 1px solid #cfdaef;
    border-radius: 10px;
    cursor: pointer;
    transition: color 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}

.subnet-prefix-grid button:hover,
.subnet-prefix-grid button:focus-visible {
    background: #e7edfc;
    border-color: var(--subnet-primary);
}

.subnet-prefix-grid button.active {
    color: #fff;
    background: var(--subnet-primary);
    border-color: var(--subnet-primary);
}

.subnet-prefix-grid button.popular:not(.active) {
    color: #183d96;
    font-weight: 900;
    background: #e9efff;
    border-color: #9fb5ec;
    box-shadow: inset 0 0 0 1px rgba(36, 87, 214, 0.08);
}

.subnet-check {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    margin-top: 1.1rem;
    font-weight: 700;
    cursor: pointer;
}

.subnet-check input {
    width: 1.15rem;
    height: 1.15rem;
    margin: 0;
    accent-color: var(--subnet-primary);
}

.subnet-results {
    margin-top: 2rem;
}

.subnet-results-heading {
    margin-bottom: 1rem;
}

.subnet-results-heading h2 {
    font-size: 1.5rem;
}

.subnet-result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 0.9rem;
    margin: 0;
}

.subnet-result {
    min-width: 0;
    min-height: 112px;
    padding: 1rem;
    background: var(--subnet-card);
    border: 1px solid var(--subnet-border);
    border-radius: 18px;
    box-shadow: 0 8px 24px rgba(23, 32, 51, 0.06);
}

.subnet-result-accent {
    background: #f4f7ff;
    border-color: #c9d6f5;
}

.subnet-result dt {
    margin-bottom: 0.45rem;
    color: var(--subnet-muted);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.subnet-result dt a {
    color: inherit;
    text-decoration: none;
}

.subnet-result dt a:hover,
.subnet-result dt a:focus {
    color: var(--subnet-primary);
    text-decoration: underline;
}

.subnet-result dd {
    margin: 0;
    overflow-wrap: anywhere;
    color: var(--subnet-text);
    font: 700 1.05rem/1.55 "Source Code Pro", Consolas, monospace;
}

.subnet-result .normtext {
    color: var(--subnet-muted);
    font: 0.8rem/1.4 system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

@media (min-width: 640px) {
    .subnet-input-row {
        grid-template-columns: minmax(0, 1fr) auto;
        align-items: end;
    }

    .subnet-calculate {
        min-width: 130px;
    }
}

@media (min-width: 992px) {
    .subnet-workspace {
        grid-template-columns: minmax(380px, 0.85fr) minmax(0, 1.35fr);
        align-items: start;
    }

    .subnet-results {
        margin-top: 0;
    }

    .subnet-result-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
        gap: 0.75rem;
    }

    .subnet-result {
        min-height: 96px;
        padding: 0.85rem;
    }

    .subnet-result dd {
        font-size: 0.95rem;
    }
}

@media (max-width: 575.98px) {
    .subnet-page {
        padding-top: 1.25rem;
    }

    .subnet-card {
        padding: 1rem;
    }

    .subnet-input-row input {
        font-size: 16px;
    }

    .subnet-result-grid {
        grid-template-columns: 1fr;
    }
}