body {
    font-family: system-ui, -apple-system, sans-serif;
    -webkit-font-smoothing: antialiased;
    text-align: center;
    background: #1a1a1a;
    color: #e2e8f0;
    margin: 0;
    padding: 0;
    min-height: 100vh;
}

h1 {
    font-size: 1.75rem;
    font-weight: 500;
    margin: 2rem 0 1rem 0;
    color: #f8fafc;
}

h2 {
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    max-width: 800px;
    color: #94a3b8;
    margin: 0 auto 2rem auto;
}

a {
    color: #60a5fa;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

button {
    background-color: #334155;
    color: #f1f5f9;
    border: 1px solid #475569;
    border-radius: 2px;
    padding: 8px 20px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.15s ease;
    margin: 10px;
}

button:hover {
    background-color: #475569;
    border-color: #64748b;
}

button.active {
    background-color: #2563eb;
    border-color: #3b82f6;
}

button.red {
    background-color: #991b1b;
    border-color: #b91c1c;
}

button:disabled {
    background-color: #1e293b;
    color: #475569;
    cursor: not-allowed;
    border-color: #1e293b;
}

#mainapp {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

#controls {
    margin: 1.5rem 0;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
}

#graphs {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1.5rem;
    margin: 2rem auto;
    padding: 1.5rem;
    max-width: 1000px;
    border-top: 1px solid #334155;
    border-bottom: 1px solid #334155;
}

.graph {
    flex: 1;
    min-width: 250px;
    text-align: center;
}

.graph h2 {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
    color: #64748b;
}

.graph span {
    display: block;
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #f1f5f9;
}

canvas {
    width: 100%;
    height: 120px;
    background: #0f172a;
    border: 1px solid #1e293b;
}

#feeds {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1.5rem;
    width: 100%;
    padding: 0 10px;
    box-sizing: border-box;
}

#feeds span {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex: 1;
    min-width: 320px;
    max-width: 640px;
}

#feeds iframe {
    width: 100%;
    aspect-ratio: 16/9;
    height: auto;
    border: 1px solid #334155;
    background: #000;
}

#feeds h3 {
    font-size: 0.85rem;
    font-weight: 400;
    color: #94a3b8;
    margin-top: 0.75rem;
    margin-bottom: 1.5rem;
}

#log, #explanation {
    max-width: 800px;
    margin: 2rem 10px;
    padding: 1.5rem;
    text-align: left;
    background: #1e293b44;
    border: 1px solid #334155;
}

@media (min-width: 820px) {
    #log, #explanation {
        margin: 2rem auto;
    }
}

#log ul {
    list-style: none;
    padding: 0;
    margin: 0;
    max-height: 150px;
    overflow-y: auto;
}

#log li {
    padding: 4px 8px;
    font-family: ui-monospace, monospace;
    font-size: 0.8rem;
    color: #cbd5e1;
    border-bottom: 1px solid #1e293b;
}

#log h2, #explanation h2 {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #f8fafc;
    margin-top: 0;
}

#explanation ol {
    padding-left: 1.25rem;
    color: #94a3b8;
}

#explanation li {
    margin-bottom: 0.75rem;
    font-size: 0.9rem;
}

.guest-check {
    margin: 1rem 0;
    line-height: 1.6;
    color: #94a3b8;
}

code {
    background: #0f172a;
    padding: 2px 4px;
    border-radius: 2px;
    color: #60a5fa;
    font-family: ui-monospace, monospace;
    font-size: 0.9em;
}

#screen {
    margin: 1rem 0;
}

select {
    padding: 6px 12px;
    border-radius: 2px;
    background: #0f172a;
    color: #f1f5f9;
    border: 1px solid #334155;
    font-size: 0.85rem;
    cursor: pointer;
}

#speedtest-legal-footer {
    margin: 3rem auto 1rem auto;
    padding-top: 0.75rem;
    max-width: 800px;
    text-align: center;
    border-top: 1px solid #2b394e;
    font-size: 0.75rem;
    line-height: 1.4;
    color: #8ca0b8;
}

#speedtest-legal-footer a {
    color: #8ca0b8;
    text-decoration: underline;
    text-underline-offset: 2px;
}

#speedtest-legal-footer a:hover {
    color: #b7c8dd;
}

#speedtest-legal-footer .divider {
    margin: 0 0.45rem;
    color: #66788f;
}

@media (max-width: 600px) {
    h1 { font-size: 1.4rem; }
    #graphs { gap: 1rem; padding: 1rem; }
    .graph { min-width: 100%; }
}