@import url('https://fonts.googleapis.com/css2?family=M+PLUS+Rounded+1c:wght@400;700&display=swap');

:root {
    --bg-color: #f0f4f8;
    --container-bg: #ffffff;
    --display-bg: #e6eaf0;
    --button-bg: #d9e2ec;
    --operator-bg: #c9d6e4;
    --action-bg: #b9c9d9;
    --equals-bg: #a8d8ea;
    --text-color: #334e68;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'M PLUS Rounded 1c', sans-serif;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: var(--bg-color);
    color: var(--text-color);
    padding: 20px;
}

#capture-area {
    background-color: var(--container-bg);
    padding: 25px;
    border-radius: 20px;
    box-shadow: 0 10px 25px var(--shadow-color);
    width: 100%;
    max-width: 420px;
}

.app-container {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

#memo-display {
    background-color: var(--display-bg);
    padding: 15px;
    border-radius: 10px;
    height: 150px;
    overflow-y: auto;
    text-align: right;
    font-size: 1em;
    line-height: 1.6;
    border: 1px solid #c9d6e4;
}

#display {
    background-color: var(--display-bg);
    color: var(--text-color);
    font-size: 2.8em;
    font-weight: 700;
    padding: 15px 20px;
    text-align: right;
    border-radius: 10px;
    word-wrap: break-word;
    word-break: break-all;
    min-height: 70px;
    border: 1px solid #c9d6e4;
}

#notes {
    background-color: var(--display-bg);
    border: 1px solid #c9d6e4;
    border-radius: 10px;
    width: 100%;
    height: 80px;
    padding: 10px;
    font-family: inherit;
    font-size: 0.95em;
    resize: vertical;
}
#notes:focus {
    outline: 2px solid var(--equals-bg);
}

.calculator-keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
}

button {
    border: none;
    border-radius: 10px;
    padding: 20px;
    font-size: 1.4em;
    font-weight: 700;
    font-family: 'M PLUS Rounded 1c', sans-serif;
    background-color: var(--button-bg);
    color: var(--text-color);
    cursor: pointer;
    transition: background-color 0.2s, box-shadow 0.2s, transform 0.1s;
    box-shadow: 0 4px 6px var(--shadow-color);
}

button:hover {
    filter: brightness(1.05);
}

button:active {
    transform: translateY(2px);
    box-shadow: 0 2px 4px var(--shadow-color);
}

button[data-action="operator"] {
    background-color: var(--operator-bg);
}

button[data-action="equals"] {
    background-color: var(--equals-bg);
    grid-column: span 2;
}

button.control-btn {
    background-color: var(--action-bg);
    font-size: 1.1em;
    margin-top: 10px;
}

#save-png {
    width: 100%;
    background-color: #a8e6cf;
    padding: 15px;
}

.footer-link {
    margin-top: 30px;
    text-align: center;
}

.footer-link a {
    color: #88a2c2;
    text-decoration: none;
    font-weight: 700;
    transition: color 0.2s;
}

.footer-link a:hover {
    color: var(--text-color);
}