* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: #f1f5f9;
    color: #0f172a;
}

.app-header {
    display: flex;
    justify-content: flex-start;
    align-items: center;
    gap: 8px;
    padding: 12px 16px;
    background: #2563eb;
    color: white;
}

.container {
    max-width: 900px;
    margin: 20px auto;
    padding: 0 16px;
}

textarea {
    width: 100%;
    min-height: 140px;
    padding: 12px;
    font-size: 14px;
    border-radius: 8px;
    border: 1px solid #cbd5e1;
    resize: vertical;
}

.buttons {
    display: flex;
    gap: 12px;
    margin: 12px 0;
    flex-wrap: wrap;
}

button {
    padding: 8px 16px;
    border-radius: 6px;
    border: none;
    background: #2563eb;
    color: white;
    cursor: pointer;
}

    button:hover {
        background: #1d4ed8;
    }

.about-btn {
    background: #f8fafc;
    color: #1e293b;
    border: 1px solid #cbd5e1;
}

    .about-btn:hover {
        background: #e2e8f0;
    }

.overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.55);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 999;
}

.hidden {
    display: none;
}

.about-modal {
    background: #ffffff;
    max-width: 720px;
    width: 90%;
    max-height: 85vh;
    overflow-y: auto;
    padding: 24px;
    border-radius: 14px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.25);
}

    .about-modal h2 {
        text-align: center;
        margin-top: 0;
    }

    .about-modal section {
        margin-bottom: 16px;
        line-height: 1.6;
        font-size: 14px;
    }

.close-btn {
    display: block;
    margin: 20px auto 0;
    background: #2563eb;
}