```css
* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f6f9;
    color: #263238;
}

/* HEADER */

header {
    background: #005083;
    color: white;
    padding: 24px 40px;
}

header h1 {
    margin: 0;
    font-size: 28px;
    font-weight: 600;
}

header p {
    margin: 7px 0 0;
    color: #e1edf5;
    font-size: 15px;
}


/* CONTENIDO */

main {
    max-width: 1400px;
    margin: 0 auto;
    padding: 30px 40px;
}

section {
    background: white;
    border-radius: 10px;
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

section h2 {
    margin: 0 0 20px 0;
    font-size: 19px;
    font-weight: 600;
    color: #17365d;
}


/* FILTRO */

#filtros {
    display: flex;
    align-items: center;
    gap: 15px;
}

#filtros h2 {
    margin: 0;
}

#filtros label {
    color: #59636e;
}

#mes {
    padding: 9px 35px 9px 12px;
    border: 1px solid #cbd3da;
    border-radius: 6px;
    background: white;
    font-size: 14px;
}


/* KPI */

.kpi-container {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
}

.kpi-card {
    border: 1px solid #e1e6eb;
    border-radius: 8px;
    padding: 20px;
    background: #fafbfc;
}

.kpi-card h3 {
    margin: 0;
    font-size: 14px;
    color: #66717c;
    font-weight: 500;
}

.kpi-value {
    margin-top: 10px;
    font-size: 30px;
    font-weight: 700;
    color: #17365d;
}

.kpi-card p {
    margin: 7px 0 0;
    font-size: 13px;
    color: #89939d;
}


/* GRAFICOS */

.graficos-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.grafico {
    border: 1px solid #e1e6eb;
    border-radius: 8px;
    padding: 20px;
}

.grafico h3 {
    margin: 0 0 15px;
    font-size: 15px;
    color: #4d5964;
}

.grafico-placeholder {
    height: 280px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f7f9fb;
    border-radius: 6px;
    color: #a0a8b0;
}


/* FALLA DESTACADA */

.falla-destacada {
    display: grid;
    grid-template-columns: 1fr 2fr 1fr;
    gap: 20px;
    background: #fff8e6;
    border-left: 5px solid #e0a100;
    border-radius: 6px;
    padding: 20px;
}

.falla-destacada div {
    display: flex;
    flex-direction: column;
    gap: 7px;
}

.etiqueta {
    font-size: 12px;
    color: #7b858e;
    text-transform: uppercase;
}

.falla-destacada strong {
    font-size: 16px;
    color: #3d454c;
}


/* TABLA */

#incidentes {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

thead {
    background: #f1f4f7;
}

th {
    text-align: left;
    padding: 12px;
    color: #59636e;
    font-weight: 600;
    border-bottom: 2px solid #dce2e7;
}

td {
    padding: 12px;
    border-bottom: 1px solid #e8ecef;
}

tbody tr:hover {
    background: #f8fafc;
}


/* RESPONSIVE */

@media (max-width: 900px) {

    main {
        padding: 20px;
    }

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

    .graficos-container {
        grid-template-columns: 1fr;
    }

    .falla-destacada {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {

    header {
        padding: 20px;
    }

    .kpi-container {
        grid-template-columns: 1fr;
    }

    #filtros {
        align-items: flex-start;
        flex-direction: column;
    }
}

/* SELECTOR DE PERÍODO */

.periodo-selector {
    position: relative;
}

#periodo-boton {
    min-width: 190px;
    padding: 10px 14px;
    border: 1px solid #cbd3da;
    border-radius: 6px;
    background: white;
    color: #263238;
    font-size: 14px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#periodo-boton:hover {
    border-color: #9da8b2;
}

.flecha {
    margin-left: 15px;
    color: #66717c;
}

.periodo-menu {
    display: none;
    position: absolute;
    top: calc(100% + 6px);
    left: 0;
    width: 210px;
    background: white;
    border: 1px solid #d5dce2;
    border-radius: 7px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.12);
    padding: 8px 0;
    z-index: 100;
}

.periodo-menu.mostrar {
    display: block;
}

.periodo-menu label {
    display: flex;
    align-items: center;
    gap: 9px;
    padding: 9px 14px;
    margin: 0;
    cursor: pointer;
    color: #3d474f;
    font-size: 14px;
}

.periodo-menu label:hover {
    background: #f3f6f9;
}

.periodo-menu input {
    width: 15px;
    height: 15px;
    cursor: pointer;
}

.grafico-container {
    position: relative;
    height: 280px;
}

/* ESTADO ACTUAL DE LOS SITIOS */

.estado-actual-subtitulo {
    margin: -10px 0 20px;
    color: #718096;
    font-size: 14px;
}

.estado-sitios {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
}

.sitio-card {
    min-width: 0;
    padding: 18px;
    border: 1px solid #e1e6eb;
    border-radius: 8px;
    background: #ffffff;
}

.sitio-card h3 {
    margin: 0 0 16px;
    color: #263238;
    font-size: 16px;
    font-weight: 600;
}

.sitio-estado {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    margin-top: 12px;
    font-size: 13px;
}

.sitio-estado-label {
    color: #66717c;
}

.estado-badge {
    display: inline-block;
    padding: 5px 9px;
    border-radius: 5px;
    font-size: 12px;
    font-weight: 600;
    text-align: center;
}

.estado-normal,
.estado-online {
    background: #e5f4f1;
    color: #2a9d8f;
}

.estado-falla,
.estado-offline {
    background: #fde8e7;
    color: #b42318;
}

.estado-indeterminado {
    background: #fff3d6;
    color: #8a5b00;
}

.estado-cargando,
.estado-error {
    color: #66717c;
    font-size: 14px;
}

@media (max-width: 900px) {
    .estado-sitios {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 600px) {
    .estado-sitios {
        grid-template-columns: 1fr;
    }
}


/* ENCABEZADO DEL DASHBOARD */
.dashboard-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
}

.header-principal {
    display: flex;
    align-items: center;
    gap: 20px;
    min-width: 0;
}

.logo-isa {
    display: block;
    width: 150px;
    max-width: 30%;
    height: auto;
    object-fit: contain;
}

.header-texto h1 {
    margin-top: 0;
    margin-bottom: 8px;
}

.header-texto p {
    margin-bottom: 0;
}

.reloj-dashboard {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 4px;
    color: #ffffffd3;
    font-size: 13px;
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
}

#reloj-hora {
    color: #81B82B;
    font-size: 20px;
    font-weight: 700;
}

@media (max-width: 600px) {
    .dashboard-header {
        align-items: flex-start;
        gap: 16px;
    }

    .header-principal {
        gap: 12px;
    }

    .logo-isa {
        width: 100px;
    }

    .reloj-dashboard {
        align-items: flex-start;
    }
}

```