:root {
    --color-text: #212529;
    --color-bg: #fff;
    --color-border: #dee2e6;
    --color-light: #f8f9fa;
    --color-primary: #0d6efd;
    --color-primary-hover: #0b5ed7;
    --color-primary-hover-border: #0a58ca;
    --color-primary-active: #0a58ca;
    --color-primary-active-border: #0a53be;
    --color-focus-input: #86b7fe;
    --ring-input: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
    --ring-button: 0 0 0 0.25rem rgba(49, 132, 253, 0.5);
    --radius: 0.375rem;
    --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
        "Noto Sans", "Liberation Sans", Arial, sans-serif;
}

/* ---------- Reset / база ---------- */

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font);
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-text-size-adjust: 100%;
}

h3 {
    margin-top: 0;
    margin-bottom: 0.5rem;
    font-size: 1.75rem;
    font-weight: 500;
    line-height: 1.2;
}

/* ---------- Карточка авторизации ---------- */

.login-card {
    width: 100%;
    max-width: 500px;
    margin: 10% auto 0;
    padding: 1rem;
    text-align: center;
    border-radius: 2rem;
    box-shadow: 0 1rem 3rem rgba(0, 0, 0, 0.175);
}

.login-form {
    margin: 100px;
}

/* ---------- Аватар ---------- */

.avatar {
    display: block;
    width: 64px;
    height: 64px;
    margin: 0 auto 1rem;
    padding: 0.5rem;
    border-radius: 50%;
    background-color: var(--color-light);
    color: #000;
}

.avatar svg {
    display: block;
    width: 100%;
    height: 100%;
    fill: currentColor;
}

/* ---------- Поля формы ---------- */

.field {
    margin-bottom: 1rem;
}

.field label {
    display: inline-block;
    margin-bottom: 0.5rem;
}

.field input {
    display: block;
    width: 100%;
    padding: 0.375rem 0.75rem;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    color: var(--color-text);
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    appearance: none;
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.field input:focus {
    border-color: var(--color-focus-input);
    outline: 0;
    box-shadow: var(--ring-input);
}

/* ---------- Кнопка ---------- */

.btn {
    display: inline-block;
    padding: 0.375rem 0.75rem;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    text-align: center;
    color: #fff;
    background-color: var(--color-primary);
    border: 1px solid var(--color-primary);
    border-radius: var(--radius);
    cursor: pointer;
    user-select: none;
    transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out,
        border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.btn:hover {
    background-color: var(--color-primary-hover);
    border-color: var(--color-primary-hover-border);
}

.btn:focus-visible {
    outline: 0;
    background-color: var(--color-primary-hover);
    border-color: var(--color-primary-hover-border);
    box-shadow: var(--ring-button);
}

.btn:active {
    background-color: var(--color-primary-active);
    border-color: var(--color-primary-active-border);
}

/* ---------- Мобильные ---------- */

@media (max-width: 576px) {
    .login-card {
        margin-top: 10%;
        max-width: calc(100% - 1.5rem);
    }

    .login-form {
        margin: 1.5rem 0.5rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    .field input,
    .btn {
        transition: none;
    }
}