*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: #f9fafb;
    color: #0a0a0b;
    min-height: 100dvh;
    display: flex;
    justify-content: center;
    padding: 2rem 1rem;
}

main {
    width: 100%;
    max-width: 480px;
}

h1 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

#send-form {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

textarea {
    width: 100%;
    padding: 0.75rem;
    font-size: 1rem;
    font-family: inherit;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    resize: vertical;
    min-height: 5rem;
    background: #fff;
}

textarea:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}

button[type="submit"] {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    color: #fff;
    background: #2563eb;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    min-height: 44px;
}

button[type="submit"]:hover {
    background: #1d4ed8;
}

button[type="submit"]:active {
    background: #1e40af;
}

button[type="submit"]:disabled {
    background: #93c5fd;
    cursor: not-allowed;
}

.feedback {
    margin-top: 0.75rem;
    padding: 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
}

.feedback--success {
    background: #f0fdf4;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.feedback--error {
    background: #fef2f2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.settings {
    margin-top: 2rem;
    font-size: 0.875rem;
    color: #545459;
}

.settings summary {
    cursor: pointer;
    user-select: none;
}

.settings label {
    display: block;
    margin-top: 0.75rem;
    margin-bottom: 0.25rem;
    font-weight: 500;
    color: #0a0a0b;
}

.settings input {
    width: 100%;
    padding: 0.5rem 0.75rem;
    font-size: 0.875rem;
    font-family: inherit;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    background: #fff;
}

.settings input:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}

.settings button {
    margin-top: 0.5rem;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: #fff;
    background: #6b7280;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    min-height: 44px;
}

.settings button:hover {
    background: #4b5563;
}