html {
    box-sizing: border-box;
}

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

body {
    margin: 0;
}

main {
    width: 98%;
    max-width: 960px;
    margin: 0 auto;
}
.header-main {
    position: fixed;
    top: 0;
    right: 0;
    left: 0;
    z-index: 100;
     background: linear-gradient(90deg, rgba(120,6,66,1) 0%, rgba(111,13,93,1) 49%, rgba(64,19,139,1) 100%);
    box-shadow: inset 0 2px 2px rgba(0, 0, 0, 0.8);
}

/**
 * .header-main h1
 * - line-height 2 times the inherited font-size
 * - float left - shrink wrap the width around the content
 * - position relative - can be positioned
 * - left: 50% find the left edge of the element and align with 50% left of parent element
 * - translateX move the element based on the element size -50% plus half the size of the hamburger
 * - this will center the h1 in the negative space to the right of the hamburger
 * - not the center of the parent element
 */
.header-main h1 {
    line-height: 2;
    float: left;
    position: relative;
    left: 50%;
    transform: translateX(calc(-50% + 32px));
    margin: 0;
    color: white;
    text-transform: uppercase;
    font-family: "Myriad Pro Regular", sans-serif;
    letter-spacing: 4px;
    text-shadow: 0 -2px 2px hsla(0, 0%, 0%, 0.6);
}

.header-main h1 sup {
    font-size: .6em;
}
.nav-main {
    position: relative;
}

/* hide the check box - input type=checkbox*/
.nav-main-menu-toggle {
    display: none;
}

/* style the checkbox's label */
.nav-main-menu-toggle-icon {
    position: fixed;
    z-index: 200;
    width: 64px;
    height: 64px;
    top: 0;
    left: 0;
    cursor: pointer;
}

/* position the span in the label - this is the hamburger of the hamburger icon */
.nav-main-menu-toggle-icon span {
    width: 80%;
    top: 50%;
    left: 10%;
    transform: translateY(-50%);
}

/**
 * .nav-main-menu-toggle-icon span
 * - build the hamburger icon
 * - ::before and ::after are pseudo elements
 * - they do not exist in the markup but we can style them
 * - every element that has content has ::before and ::after
 * - each line is 6px tall with a 3px border radius
 */
.nav-main-menu-toggle-icon span::before,
.nav-main-menu-toggle-icon span,
.nav-main-menu-toggle-icon span::after {
    background-color: black;
    height: 6px;
    position: absolute;
    content: '';
     transition: all .25s ease-in;
}

.nav-main-menu-toggle-icon span::before {
    width: 100%;
    top: -10px;
}

.nav-main-menu-toggle-icon span::after {
    width: 100%;
    top: 10px;
}

/**
 * .element ~ element
 * - is the General sibling combinator
 * - find .nav-main-menu-toggle:checked
 * - when the input is checked...
 * - style the .nav-main-menu-toggle-icon span
 * - a trick to use the input type="checkbox" to trigger changes in our layout
 */
.nav-main-menu-toggle:checked~.nav-main-menu-toggle-icon span {
    background-color: transparent;
}

.nav-main-menu-toggle:checked~.nav-main-menu-toggle-icon span::before,
.nav-main-menu-toggle:checked~.nav-main-menu-toggle-icon span::after {
    top: 0;
}

.nav-main-menu-toggle:checked~.nav-main-menu-toggle-icon span::before {
    transform: rotate(-135deg);
}

.nav-main-menu-toggle:checked~.nav-main-menu-toggle-icon span::after {
    transform: rotate(135deg);
}
ul.nav-main-menu{
    list-style-type: none;
    padding: 0
}

/* style the UL left 0 width 0 can not be seen */
.nav-main-menu {
    position: fixed;
    z-index: 50;
    top: 4em;
    left: 0;
    width: 0;
    height: calc(100vh - 3em);
    transition:
        width .5s .25s ease-in,
        box-shadow .25s ease-in;
    background-color: white;
    box-shadow: none;
    overflow-y: auto;
}

/* when input checked show the UL */
.nav-main-menu-toggle:checked~.nav-main-menu {
    width: 35vw;

}

/* style the anchor */
.nav-main-menu a {
    position: relative;
    display: block;
    font-family: "Gill Sans", "Gill Sans MT", "Myriad Pro", "DejaVu Sans Condensed", Helvetica, Arial, "sans-serif";
    font-size: 1.5em;
    line-height: 2;
    font-weight: 300;
    text-transform: uppercase; 
    color: black;
    text-decoration: none;
    text-indent: 1.25rem;
    margin: 4px 0;
    transition: all .25s ease-in;
}

/* create and style the anchor's ::before pseudo element */
.nav-main-menu a::before {
    position: absolute;
    z-index: -1;
    top: 0;
    bottom: 0;
    transform: translateX(-280%);
    content: "";
    display: inline-block;
    width: 10px;
    transition: inherit;
}

/* style anchor :hover */
.nav-main-menu a:hover {
    text-indent: 2.0rem;
}

/* style the ::before when :hover on anchor */
.nav-main-menu a:hover::before {
    transform: translateX(25vw);

}
.callout {
    font-family: sans-serif;
    background: linear-gradient(90deg, rgba(120,6,66,1) 0%, rgba(111,13,93,1) 49%, rgba(64,19,139,1) 100%);
    padding: 12px;
    border-radius: 8px;
}

.callout-heading {
    color: white;
    font-size: 3em;
    text-transform: uppercase;
    margin: 0 0 32px;
}

.callout-intro {
    color: white;
    font-size: 1.5em;
    margin: 0 0 16px;
}

.subscribe-newsletter {
    --color-white-20: hsla(0, 0%, 100%, 0.20);
    --color-white-40: hsla(0, 0%, 100%, 0.40);
    --color-white-60: hsla(0, 0%, 100%, 0.60);
    --color-white-80: hsla(0, 0%, 100%, 0.80);
    --color-black-20: hsla(0, 0%, 0%, 0.20);
    --color-black-40: hsla(0, 0%, 0%, 0.40);
    --color-black-60: hsla(0, 0%, 0%, 0.60);
    --color-black-80: hsla(0, 0%, 0%, 0.80);
    --color-button-dark: hsla(266, 47%, 30%, 1.00);
    --color-button-light: hsla(54, 86%, 58%, 1.00);
    --z-index: -1;
}

.subscribe-newsletter {
    transition: all 1s ease-in;
    background: var(--color-white-20);
    border-radius: .5em;
}

.subscribe-newsletter {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: stretch;
    overflow: hidden;
}

.subscribe-newsletter fieldset {
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 0;
    margin: 0;
    border: none;
}

.subscribe-newsletter fieldset:first-child {
    flex: 1 1 auto;
}

.subscribe-newsletter fieldset:last-child::after {
    content: "";
    position: absolute;
    width: 100%;
    height: 100%;
    background: url("images/loader-circles-spin.svg") no-repeat center;
    z-index: var(--z-index, -1);
}

.subscribe-newsletter input:not([type="radio"]):not([type="checkbox"]) {
    -webkit-appearance: none;
    border: none;
    border-radius: 0;
}

.subscribe-newsletter input {
    position: relative;
    font-family: inherit;
    font-size: 1.2em;
    line-height: 2.4;
    letter-spacing: 0.05em;
    padding: 0 .5em;
    margin: 0;
    color: var(--color-button-dark);
}

.subscribe-newsletter input[type=email] {
    background: var(--color-white-60);
}

.subscribe-newsletter input[type=email]:focus {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--color-button-dark);
}

.subscribe-newsletter input::placeholder {
    position: relative;
    color: var(--color-button-dark);
    opacity: .4
}

.subscribe-newsletter input::placeholder {
    transition: 2s cubic-bezier(1, 1.65, 0.35, 1.32), opacity .25s ease;
}

.subscribe-newsletter input:focus::placeholder {
    transform: translateX(100%);
    transition: transform 1s cubic-bezier(0.15, 0.69, 0.7, -0.42), opacity 2s ease;
    opacity: 0
}

.subscribe-newsletter input[type=submit],
.subscribe-newsletter input[type=submit]:invalid {
    background: var(--color-button-dark);
    color: white;
    font-weight: bold;
    text-transform: uppercase;
    padding: 0 1em;
    transition: all 1s .5s ease-in;
    transform-origin: right center;
    transform: scale(1);
    box-shadow: 0 0 0px 0px var(--color-black-60);
}

.subscribe-newsletter:valid input[type=submit] {
    color: var(--color-button-dark);
    background: var(--color-button-light);
    transform: scale(1);
    box-shadow: -2px 2px 4px var(--color-black-60), -2px -2px 4px var(--color-black-60);
}

.subscribe-newsletter fieldset input[type=submit]:disabled {
    background: var(--color-white-80);
    color: black;
    transform: scale(1);
    box-shadow: 0 0 0px 0px var(--color-black-60);
}

.subscribe-newsletter label {
    color: var(--color-white-80);
    line-height: 1.625em;
    padding: 0 .5em;
}

.subscribe-newsletter.sending {
    background: var(--color-white-60);
}

.subscribe-newsletter.received {
    background: var(--color-white-20);
}

.subscribe-newsletter .subscribe-newsletter-message-error {
    background: var(--color-button-dark);
}

.subscribe-newsletter .subscribe-newsletter-message-success {
    background: var(--color-white-80);
    color: var(--color-button-dark);
    font-size: 1.6em;
    flex: 1;
    text-align: center;
}

@media (min-width: 768px) {
     .nav-main-menu-toggle,
    .nav-main-menu-toggle-icon {
        display: none;
    }
        /*  override size and position of header */
    .header-main {
        position: static;
        height: 120px;
        border-radius: 10px;
        border: 2px solid hsl(0, 0%, 50%);
        margin: 20px;
    }

    .header-main h1 {
        line-height: 120px;
        font-size: 2.75em;
        transform: translateX(-50%);
    }

    /*  override and reset to no style */
    .nav-main-menu {
        display: flex;
        justify-content: space-evenly;
        position: relative;
        z-index: 0;
        top: auto;
        left: auto;
        width: auto;
        height: auto;
        transition: none;
        background-color: transparent;
        box-shadow: none;
        overflow: hidden;
        padding: 0 20px;
    }

    /*  override and reset to no style */
    .nav-main-menu-toggle:checked~.nav-main-menu {
        width: auto;
        box-shadow: none;
    }

    /*  override and basic style for navigation large screen */
    .nav-main-menu a {
        position: static;
        display: block;
        text-indent: 0;
        padding: 0 1em;
        border: 1px solid black;
        border-radius: 5px;
        transition: all .25s linear;
       ;
    }

    /*  hide the a:::before */
    .nav-main-menu a::before {
        display: none;
    }

    /*  basic style for navigation large screen */
    .nav-main-menu a:hover {
        text-indent: 0;
        color: hsl(213, 100%, 44%);
        background-color: hsl(0, 0%, 100%);
        box-shadow: 0 0px 0px currentColor;
    }

    .nav-main-menu a:active {
        text-indent: 0;
        color: hsl(213, 100%, 44%);
        background-color: hsl(0, 0%, 100%);
        box-shadow: inset 0 0px 4px currentColor;
    }
    .callout {
        padding: 80px;
    }
    .subscribe-newsletter {
        flex-direction: row;
        height: 8em;
        align-items: center;
    }
    .subscribe-newsletter:valid input[type=submit] {
        transform: scale(1.2);
    }
}