/* =========================================================
   Topology Explorer Widget
   Topic: 2.02 Network Topologies
   ========================================================= */

.topology-widget {
    margin: 1.5rem 0;
    padding: 1.25rem;
    border: 1px solid #e2e8f0;
    border-radius: 24px;
    background: #f8fafc;
    box-shadow: 0 12px 32px rgba(15, 23, 42, 0.06);
}

.topology-control-group {
    margin-bottom: 1rem;
}

.control-label {
    display: block;
    margin-bottom: 0.55rem;
    color: #334155;
    font-weight: 700;
}

.topology-button-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.55rem;
}

.topology-btn,
.message-btn {
    appearance: none;
    border: 1px solid #cbd5e1;
    background: white;
    color: #334155;

    padding: 0.55rem 0.9rem;
    border-radius: 999px;

    font-size: 0.92rem;
    font-weight: 650;

    cursor: pointer;
    transition: all 0.2s ease;
}

.topology-btn:hover,
.message-btn:hover {
    border-color: #0f172a;
    color: #0f172a;
    transform: translateY(-1px);
}

.topology-btn.active,
.message-btn.active {
    background: #0f172a;
    border-color: #0f172a;
    color: white;
}

.message-btn:disabled {
    opacity: 0.45;
    cursor: not-allowed;
    transform: none;
}

.topology-action-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    margin: 1rem 0 1.1rem;
}

.topology-secondary-btn {
    background: white;
    color: #334155;
    border: 1px solid #cbd5e1;
}

.topology-secondary-btn:hover {
    background: #f1f5f9;
    color: #0f172a;
    border-color: #94a3b8;
}

.topology-secondary-btn:disabled {
    opacity: 0.45;
    cursor: not-allowed;
    transform: none;
    background: #f8fafc;
    color: #94a3b8;
    border-color: #e2e8f0;
}

.topology-visual-card {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 22px;
    overflow: hidden;
}

.topology-svg {
    display: block;
    width: 100%;
    height: auto;
    min-height: 320px;
    background:
        radial-gradient(circle at top left, rgba(219, 234, 254, 0.75), transparent 35%),
        linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
}

.topology-svg text {
    font-family: Inter, Arial, sans-serif;
    user-select: none;
}

.topology-link {
    stroke: #94a3b8;
    stroke-width: 5;
    stroke-linecap: round;
}

.topology-link.shared-link {
    stroke-width: 7;
}

.topology-link.failed-link {
    stroke: #ef4444;
    stroke-dasharray: 10 8;
}

.topology-node circle,
.topology-node rect {
    fill: white;
    stroke: #475569;
    stroke-width: 3;
    transition: all 0.25s ease;
}

.topology-node text {
    fill: #0f172a;
    font-size: 18px;
    font-weight: 750;
    text-anchor: middle;
    dominant-baseline: middle;
}

.topology-node.sender circle,
.topology-node.sender rect {
    fill: #dbeafe;
    stroke: #2563eb;
}

.topology-node.receiver circle,
.topology-node.receiver rect {
    fill: #dcfce7;
    stroke: #16a34a;
}

.topology-node.selected-receiver circle,
.topology-node.selected-receiver rect {
    fill: #f3e8ff;
    stroke: #9333ea;
}

.topology-node.failed-node circle,
.topology-node.failed-node rect {
    fill: #fee2e2;
    stroke: #dc2626;
}

.topology-node.pulse circle,
.topology-node.pulse rect {
    animation: topologyNodePulse 0.8s ease;
}

@keyframes topologyNodePulse {
    0% {
        transform: scale(1);
    }

    40% {
        transform: scale(1.12);
    }

    100% {
        transform: scale(1);
    }
}

.topology-packet {
    fill: #2563eb;
    stroke: white;
    stroke-width: 3;
    filter: drop-shadow(0 4px 10px rgba(37, 99, 235, 0.38));
}

.topology-packet.multicast-packet {
    fill: #9333ea;
}

.topology-packet.broadcast-packet {
    fill: #ea580c;
}

.topology-central-label,
.topology-lan-label {
    fill: #64748b;
    font-size: 16px;
    font-weight: 700;
}

.topology-explanation-panel {
    margin-top: 1rem;
    padding: 1rem 1.1rem;
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 18px;
}

.topology-explanation-panel h3 {
    margin-top: 0;
    margin-bottom: 0.45rem;
}

.topology-explanation-panel p {
    margin-bottom: 0.55rem;
}

.topology-status {
    min-height: 1.6rem;
    color: #475569;
    font-weight: 650;
}

.topology-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 0.9rem 1.2rem;
    margin-top: 1rem;
    color: #475569;
    font-size: 0.9rem;
    font-weight: 600;
}

.topology-legend span {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
}

.legend-dot {
    display: inline-block;
    width: 14px;
    height: 14px;
    border-radius: 999px;
    border: 2px solid transparent;
}

.sender-dot {
    background: #dbeafe;
    border-color: #2563eb;
}

.receiver-dot {
    background: #dcfce7;
    border-color: #16a34a;
}

.selected-dot {
    background: #f3e8ff;
    border-color: #9333ea;
}

.legend-line {
    display: inline-block;
    width: 24px;
    height: 0;
    border-top: 4px solid #94a3b8;
    border-radius: 999px;
}

/* =========================================================
   Responsive adjustments
   ========================================================= */

@media (max-width: 700px) {
    .topology-widget {
        padding: 1rem;
    }

    .topology-btn,
    .message-btn {
        font-size: 0.86rem;
        padding: 0.5rem 0.75rem;
    }

    .topology-action-row {
        display: grid;
        grid-template-columns: 1fr;
    }

    .topology-action-row .small-button {
        justify-content: center;
    }

    .topology-svg {
        min-height: 260px;
    }

    .topology-node text {
        font-size: 16px;
    }

    .topology-central-label,
    .topology-lan-label {
        font-size: 14px;
    }
}