:root {
    --font: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    font-family: var(--font);
    padding: 2rem;
    background: linear-gradient(to bottom right, #f0f4f8, #e2e8f0);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: safe center;
    min-height: 100vh;
    margin: 0;
    color: #333;
    box-sizing: border-box;
}

body *,
body::before,
body::after {
    box-sizing: inherit;
}

h2 {
    color: #007BFF;
    margin-bottom: 2rem;
    text-align: center;
    font: 300 2.5rem/1.2 var(--font);
}

p {
    text-align: center;
    font-style: italic;
    color: #eee;
    margin-block: -1.5rem 1.5rem;
    background: hsl(0, 0%, 43%);
    padding: 0.5ch 1ch;
    border-radius: 1ch;
    box-shadow: 0 0 3px 1px #777;
}

form {
    background-color: #fff;
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    width: max(500px, 90%);
    margin: 0 auto;

    .field-group {
        margin-bottom: 1.5rem;
        position: relative;

        &:last-of-type {
            margin-bottom: 2rem;
        }

        label {
            display: block;
            margin-bottom: 0.6rem;
            font: 600 .875rem var(--font);
            color: #4A5568;
            transition: color 0.3s ease;
        }

        &:focus-within label {
            color: #007BFF;
        }
    }

    .input-container {
        position: relative;

        &:has(#password, #password-js) {

            #css-password-reveal-toggle {
                display: none;

                &:checked+*+* {
                    display: none;
                }

                &:not(:checked)+*+*+* {
                    display: none;
                }

                &:checked {
                    ~input#password {
                        -webkit-text-security: none;
                        -moz-text-security: none;
                    }
                }

                &:not(:checked) {
                    ~input#password {
                        -webkit-text-security: disc;
                        -moz-text-security: disc;

                        &::placeholder {
                            -webkit-text-security: none;
                            -moz-text-security: none;
                        }
                    }
                }
            }

            #password {
                padding-right: 5.5rem;
            }

            .password-reveal-toggle-btn {
                position: absolute;
                inset: 50% 5.5ch auto auto;
                translate: 0 -50%;
            }

            #eye,
            #js-eye {
                -webkit-mask: url('eye.svg') no-repeat center;
                mask: url('eye.svg') no-repeat center;
            }

            #eye-off,
            #js-eye-off {
                -webkit-mask: url('eye-off.svg') no-repeat center;
                mask: url('eye-off.svg') no-repeat center;
            }

            #eye,
            #eye-off,
            #js-eye,
            #js-eye-off {
                width: 24px;
                height: 24px;
                -webkit-mask-size: contain;
                mask-size: contain;
                display: block;
                background: #4d4e5095;
            }
        }

        input {
            width: 100%;
            padding: 0.9rem 3rem 0.9rem 0.9rem;
            border: 1px solid #CBD5E0;
            border-radius: 6px;
            font-size: 1rem;
            color: #2D3748;
            background-color: #fff;
            transition: border-color 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;

            &::placeholder {
                color: #A0AEC0;
                font-style: italic;
            }

            &:placeholder-shown,
            &:required:placeholder-shown:not(:focus) {
                border-color: #CBD5E0;

                ~.validation-indicator[valid][user-valid],
                ~.validation-indicator[invalid][user-invalid] {
                    opacity: 0;
                    transform: translateY(-50%) scale(0.5);
                }
            }

            &:focus {
                outline: none;
                border-color: #007BFF;
                box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.2);
                background-color: #f7fafc;
            }

            &:not(:required):placeholder-shown,
            &:required:placeholder-shown:not(:focus) {
                border-color: #CBD5E0;

                ~.validation-indicator[valid][user-valid],
                ~.validation-indicator[invalid][user-invalid] {
                    opacity: 0;
                    transform: translateY(-50%) scale(0.5);
                }
            }

            &:valid:not(:placeholder-shown),
            &:user-valid:not(:placeholder-shown) {
                border-color: #38A169;

                ~.validation-indicator[valid][user-valid] {
                    opacity: 1;
                    color: #38A169;
                    transform: translateY(-50%) scale(1);
                }

                ~.validation-indicator[invalid][user-invalid] {
                    opacity: 0;
                    transform: translateY(-50%) scale(0.5);
                }
            }

            &:user-valid:not(:placeholder-shown) {
                background-color: #f0fff4;
                border-color: #38A169 !important;
            }

            &:invalid:not(:placeholder-shown),
            &:user-invalid:not(:placeholder-shown) {
                border-color: #E53E3E;

                ~.validation-indicator[invalid][user-invalid] {
                    opacity: 1;
                    color: #E53E3E;
                    transform: translateY(-50%) scale(1);
                }

                ~.validation-indicator[valid][user-valid] {
                    opacity: 0;
                    transform: translateY(-50%) scale(0.5);
                }
            }

            &:user-invalid:not(:placeholder-shown) {
                background-color: #fff5f5;
                border-color: #E53E3E !important;
            }

            &:user-invalid:not(:required):placeholder-shown {
                background-color: #fff5f5;
                border-color: #E53E3E !important;
            }
        }

        .validation-indicator {
            position: absolute;
            right: 1rem;
            top: 50%;
            transform: translateY(-50%) scale(0.5);
            font-size: 1.25rem;
            opacity: 0;
            transition: opacity 0.25s ease-out, transform 0.25s cubic-bezier(0.175, 0.885, 0.32, 1.275), color 0.2s;
            pointer-events: none;
            line-height: 1;
        }


        check {
            background-color: green;
            -webkit-mask: url('check.svg') no-repeat center;
            mask: url('check.svg') no-repeat center;
        }

        x {
            background-color: red;
            -webkit-mask: url('cross.svg') no-repeat center;
            mask: url('cross.svg') no-repeat center;
        }

        check,
        x {
            width: 24px;
            height: 24px;
            -webkit-mask-size: contain;
            mask-size: contain;
            display: block;
        }
    }

    button[type="submit"] {
        margin-top: 1rem;
        padding: 0.9rem 1.5rem;
        font-size: 1.1rem;
        font-weight: 600;
        background: linear-gradient(to right, #007BFF 0%, #0056b3 50%, #007BFF 100%) left center / 200% auto;
        color: white;
        border: none;
        border-radius: 8px;
        cursor: pointer;
        transition: background-position 0.4s ease-out, transform 0.15s ease-out, box-shadow 0.2s ease-out;
        display: block;
        width: 100%;
        text-transform: uppercase;
        letter-spacing: 0.5px;
        box-shadow: 0 4px 12px rgba(0, 100, 255, 0.25);

        &:hover {
            background-position: right center;
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(0, 100, 255, 0.35);
        }

        &:active {
            transform: translateY(0px);
            box-shadow: 0 2px 8px rgba(0, 100, 255, 0.2);
            background-image: linear-gradient(to right, #0056b3, #004085);
        }

        &:disabled {
            background-image: none;
            background-color: #cccccc;
            color: #888888;
            cursor: not-allowed;
            box-shadow: none;
            transform: none;
        }
    }

    note {
        display: block;
        background-color: #f0f8ff;
        border-left: 4px solid #007BFF;
        padding: 1em;
        margin: 1.5em 0;
        font-family: sans-serif;
        font-size: 0.95rem;
        color: #333;
        border-radius: 5px;

        ul {
            padding-left: 1.2em;
            margin: 0.5em 0 0 0;
        }

        li {
            margin-bottom: 0.5em;
        }

        code {
            background-color: #eef;
            padding: 0.1em 0.3em;
            border-radius: 3px;
            font-family: monospace;
        }
    }
}