body {
        font-family: 'Roboto', Arial, sans-serif;
        background-color: #f0f0f0;
        display: flex;
        justify-content: center;
        align-items: center;
        min-height: 100vh;
        margin: 0;
        padding: 20px;
        box-sizing: border-box;
    }

    .samsung-phone {
        width: 360px;
        background: linear-gradient(145deg, #1a1a1a, #2a2a2a);
        border-radius: 40px;
        padding: 20px;
        box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5);
        position: relative;
        overflow: hidden;
        border: 12px solid #000;
    }

    .phone-notch {
        position: absolute;
        top: 0;
        left: 50%;
        transform: translateX(-50%);
        width: 40%;
        height: 20px;
        background: #000;
        border-bottom-left-radius: 15px;
        border-bottom-right-radius: 15px;
        z-index: 10;
    }

    .screen {
        background: #000;
        border-radius: 30px;
        padding: 20px;
        color: #fff;
        position: relative;
        overflow: hidden;
    }

    .status-bar {
        display: flex;
        justify-content: space-between;
        font-size: 12px;
        margin-bottom: 20px;
        color: #fff;
    }

    .app-title {
        text-align: center;
        font-size: 24px;
        margin-bottom: 30px;
        color: #4a90e2;
        font-weight: 500;
    }

    .input-container {
        margin-bottom: 20px;
    }

    #user-input {
        width: 100%;
        padding: 15px;
        border-radius: 10px;
        border: none;
        background: #333;
        color: #fff;
        font-size: 16px;
        box-sizing: border-box;
        margin-bottom: 10px;
    }

    #user-input::placeholder {
        color: #888;
    }

    .button-container {
        display: flex;
        justify-content: space-between;
        margin-bottom: 20px;
    }

    button {
        flex: 1;
        padding: 15px;
        border-radius: 10px;
        border: none;
        font-size: 16px;
        font-weight: bold;
        cursor: pointer;
        transition: all 0.2s;
    }

    #check-btn {
        background: #4a90e2;
        color: white;
        margin-right: 10px;
    }

    #check-btn:active {
        background: #3a7bc8;
        transform: scale(0.98);
    }

    #clear-btn {
        background: #e74c3c;
        color: white;
    }

    #clear-btn:active {
        background: #c0392b;
        transform: scale(0.98);
    }

    #results-div {
        background: #333;
        padding: 15px;
        border-radius: 10px;
        min-height: 60px;
        font-size: 16px;
        line-height: 1.5;
    }

    .valid {
        color: #2ecc71;
    }

    .invalid {
        color: #e74c3c;
    }

    .home-button {
        width: 120px;
        height: 5px;
        background: #444;
        border-radius: 5px;
        margin: 20px auto 0;
        cursor: pointer;
    }

    .home-button:active {
        background: #666;
    }

    .camera {
        position: absolute;
        top: 15px;
        right: 15px;
        width: 12px;
        height: 12px;
        background: #222;
        border-radius: 50%;
        border: 2px solid #444;
    }