:root {
    --primary-color: #4A90E2;
    --secondary-color: #F39C12;
    --text-color: #333;
    --bg-color: #F5F7FA;
    --card-bg: #FFFFFF;
    --border-color: #E1E8ED;
    --success-color: #27AE60;
    --shadow: 0 2px 8px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
}

h1 {
    text-align: center;
    color: var(--primary-color);
    font-size: 28px;
    margin-bottom: 30px;
    font-weight: 600;
}

#temperature-form {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.input-group {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 25px;
    gap: 10px;
}

#temperature {
    font-size: 48px;
    width: 180px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 15px;
    text-align: center;
    transition: border-color 0.3s;
    appearance: textfield;
}

#temperature::-webkit-inner-spin-button,
#temperature::-webkit-outer-spin-button {
    opacity: 1;
    height: 60px;
}

#temperature:focus {
    outline: none;
    border-color: var(--primary-color);
}

.unit {
    font-size: 36px;
    color: var(--text-color);
    font-weight: 500;
}

.submit-btn {
    width: 100%;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 16px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.1s;
}

.submit-btn:hover {
    background-color: #3A7BC8;
}

.submit-btn:active {
    transform: scale(0.98);
}

#records-section {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 25px;
    box-shadow: var(--shadow);
}

h2 {
    font-size: 20px;
    margin-bottom: 20px;
    color: var(--text-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 10px;
}

#records-list {
    max-height: 400px;
    overflow-y: auto;
}

.record-item {
    padding: 12px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.2s;
}

.record-item:hover {
    background-color: var(--bg-color);
}

.record-item:last-child {
    border-bottom: none;
}

.record-date {
    font-size: 14px;
    color: #666;
}

.record-temp {
    font-size: 20px;
    font-weight: 600;
    color: var(--primary-color);
}

.delete-btn {
    background-color: #E74C3C;
    color: white;
    border: none;
    border-radius: 4px;
    padding: 5px 10px;
    font-size: 12px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.delete-btn:hover {
    background-color: #C0392B;
}

.empty-message {
    text-align: center;
    padding: 40px 20px;
    color: #999;
    font-size: 14px;
}

@media (max-width: 480px) {
    .container {
        padding: 15px;
    }

    h1 {
        font-size: 24px;
        margin-bottom: 20px;
    }

    #temperature-form {
        padding: 20px;
    }

    #temperature {
        font-size: 36px;
        width: 140px;
        padding: 12px;
    }

    .unit {
        font-size: 28px;
    }

    .submit-btn {
        font-size: 16px;
        padding: 14px;
    }

    .record-item {
        padding: 10px;
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }

    .record-temp {
        font-size: 18px;
    }
}

@media (prefers-color-scheme: dark) {
    :root {
        --text-color: #E1E8ED;
        --bg-color: #1A1A2E;
        --card-bg: #16213E;
        --border-color: #3A3A5C;
    }

    #temperature {
        background-color: var(--card-bg);
        color: var(--text-color);
    }

    .record-date {
        color: #AAB8C2;
    }
}