* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: 'Noto Sans Myanmar', 'Myanmar Text', system-ui, -apple-system, sans-serif;
    background: #f4f6f8;
    color: #1a1a1a;
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.app-header {
    background: #1f4e3d;
    color: #fff;
    padding: 1rem 1.5rem;
}

.app-header h1 {
    margin: 0;
    font-size: 1.3rem;
}

.app-header p {
    margin: 0.25rem 0 0;
    font-size: 0.85rem;
    opacity: 0.85;
}

.chat-window {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.message {
    max-width: 75%;
    padding: 0.6rem 0.9rem;
    border-radius: 0.75rem;
    line-height: 1.5;
    white-space: pre-wrap;
}

.message.user {
    align-self: flex-end;
    background: #1f4e3d;
    color: #fff;
}

.message.assistant {
    align-self: flex-start;
    background: #fff;
    border: 1px solid #ddd;
}

.message.error {
    align-self: center;
    background: #fdecea;
    color: #a33;
    border: 1px solid #f5c2c0;
}

.chat-form {
    display: flex;
    gap: 0.5rem;
    padding: 1rem 1.5rem;
    background: #fff;
    border-top: 1px solid #ddd;
}

.chat-form textarea {
    flex: 1;
    resize: none;
    height: 3rem;
    padding: 0.6rem;
    font-size: 1rem;
    border: 1px solid #ccc;
    border-radius: 0.5rem;
    font-family: inherit;
}

.chat-form button {
    padding: 0 1.25rem;
    background: #1f4e3d;
    color: #fff;
    border: none;
    border-radius: 0.5rem;
    font-size: 1rem;
    cursor: pointer;
}

.chat-form button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}