/* Google Fonts Import */
@import url('https://fonts.googleapis.com/css2?family=Ubuntu:ital,wght@0,300;0,400;0,500;0,700;1,300;1,400;1,500;1,700&display=swap');

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

body {
    font-family: "Ubuntu", sans-serif;
    background-color: #f1f5f9;
    position: relative;
}

html {
    font-size: 18px;
}

/* ------------------------------ root variables styling -------------------------------- */

:root {
    /* common button */
    --commonBtn-primary-bg: #0f172a;
    --commonBtn-primary-hover-bg: #1e293b;
    --commonBtn-primary-color: #ffffff;
    --commonBtn-box-shadow-color: rgba(15, 23, 42, 0.15);

    /* common button */
    --crossIcon-primary-color: #64748b;
    --crossIcon-hover-primary-color: #0f172a;

    /* gameHeader */
    --gameHeader-h1-color: #0f172a;

    /* statBadge */
    --statBadge-primary-bg: #ffffff;
    --statBadge-primary-color: #334155;
    --statBadge-box-shadow-color: rgba(0, 0, 0, 0.04);
    --statBadge-border-color: #e2e8f0;

    /* gameGrid */
    --gameGrid-primary-bg: #ffff;

    /* gameCard */
    --gameCard-primary-bg: #1e293b;
    --gameCard--hover-bg: #334155;
    --gameCard-box-shadow-color: rgba(15, 23, 42, 0.08);

    /* gameCard -> flipped */
    --gameCard-flipped-bg: #ffffff;
    --gameCard-flipped-border-color: #cbd5e1;
    --gameCard-flipped-box-shadow-bg: rgba(0, 0, 0, 0.05);

    /* gameCard -> matched */
    --gameCard-matched-bg: #a7f3d0;
    --gameCard-matched-border-color: #10b981;
    --gameCard-matched-box-shadow-bg: rgba(16, 185, 129, 0.04);

    /* popUp */
    --popUp-primary-bg: rgba(255, 255, 255, 0.9);
    --popUp-border-color: rgba(255, 255, 255, 0.6);

    /* restartPopUp */
    --restartPopUp-primary-bg: rgba(255, 255, 255, 0.95);
    --restartPopUp-border-color: rgba(255, 255, 255, 0.6);

    /* matchTextStyle */
    --matchTextStyle-primary-bg: #10b981;
    --matchTextStyle-primary-color: #ffffff;
    --matchTextStyle-border-color: rgba(16, 185, 129, 0.4);

}

/* ------------------------------ common elements styling -------------------------------- */

.commonBtn {
    background-color: var(--commonBtn-primary-bg);
    color: var(--commonBtn-primary-color);
    border: none;
    padding: 10px 24px;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: 12px;
    cursor: pointer;
    box-shadow: 0 4px 6px -1px var(--commonBtn-box-shadow-color);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.commonBtn:hover {
    background-color: var(--commonBtn-primary-hover-bg);
    transform: translateY(-2px);
    box-shadow: 0 6px 12px -2px rgba(15, 23, 42, 0.2);
}

.commonBtn:active {
    transform: translateY(0);
}

.crossIcon {
    position: absolute;
    top: 20px;
    right: 24px;
    font-size: 1.5rem;
    color: var(--crossIcon-primary-color);
    cursor: pointer;
    transition: color 0.2s ease;
}

.crossIcon:hover {
    color: var(--crossIcon-hover-primary-color);
}

/* ------------------------------ header styling -------------------------------- */

.gameHeader {
    width: 90%;
    max-width: 550px;
    margin: 0.7rem auto 1rem auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-family: system-ui, -apple-system, sans-serif;

}

.gameHeader h1 {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--gameHeader-h1-color);
    margin: 0;
    letter-spacing: -0.5px;
}

.statBadge {
    background-color: var(--statBadge-primary-bg);
    color: var(--statBadge-primary-color);
    padding: 8px 16px;
    border-radius: 9999px;
    font-size: 0.9rem;
    font-weight: 600;
    box-shadow: 0 2px 8px var(--statBadge-box-shadow-color);
    border: 1px solid var(--statBadge-border-color);
}

/* ------------------------------ main container styling -------------------------------- */

.gameContainer {
    width: 100%;
    padding: 0 20px 3rem 20px;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    box-sizing: border-box;
}

#gameGrid {
    width: 60vw;
    max-width: 600px;
    aspect-ratio: 1 / 1;
    background-color: var(--gameGrid-primary-bg);
    box-shadow: 0 12px 30px -5px rgba(0, 0, 0, 0.05),
        0 4px 12px -4px rgba(0, 0, 0, 0.03);

    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, 1fr);
    grid-gap: 14px;
    padding: 18px;
    border-radius: 24px;
    perspective: 1000px;
}

.gameCard {
    aspect-ratio: 1 / 1;
    height: 100%;
    border: none;
    border-radius: 14px;
    font-size: 3.0rem;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--gameCard-primary-bg);
    color: transparent;
    cursor: pointer;
    transition: 0.25s ease;
    box-shadow: 0 4px 8px -1px var(--gameCard-box-shadow-color);

    transform: rotateY(0deg) translateY(0);
    transition: 0.3s ease;

    /* blocks dragging on cardBox */
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -webkit-user-drag: none;
}

.gameCard:hover {
    background-color: var(--gameCard--hover-bg);
    transform: rotateY(0deg) translateY(-4px);
}

.gameCard.flipped {
    color: initial;
    background-color: var(--gameCard-flipped-bg);
    border: 2px solid var(--gameCard-flipped-border-color);
    box-shadow: 0 10px 15px -3px var(--gameCard-flipped-box-shadow-bg);
    transform: rotateY(360deg) translateY(0);
}

.gameCard.matched {
    background-color: var(--gameCard-matched-bg);
    border: 2px solid var(--gameCard-matched-border-color);
    box-shadow: inset 0 2px 4px 0 var(--gameCard-matched-box-shadow-bg);
    transform: scale(0.96) translateY(0deg);
    pointer-events: none;
}

/* ------------------------------ popUp styling -------------------------------- */

#popUp {
    width: 90%;
    max-width: 700px;
    min-height: 300px;
    display: none;
    flex-direction: column;
    justify-content: space-around;
    align-items: center;
    gap: 20px;
    padding: 32px 24px;

    background-color: var(--popUp-primary-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--popUp-border-color);
    border-radius: 28px;
    box-shadow: 0px 0px 300px 100px #000;

    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 5000;
}

.proTip {
    text-align: center;
}

/* ------------------------------ restartPopUp styling -------------------------------- */

.restartPopUp {
    width: 90%;
    max-width: 700px;
    min-height: 300px;
    padding: 30px 20px;
    border: 1px solid var(--restartPopUp-border-color);
    border-radius: 28px;
    background-color: var(--restartPopUp-primary-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    box-shadow: 0px 0px 300px 100px #000;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 5000;
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 20px;
}

/* ------------------------------ matchTextStyle styling -------------------------------- */

.matchTextStyle {
    width: auto;
    min-width: 280px;
    height: auto;
    padding: 20px 40px;
    background-color: var(--matchTextStyle-primary-bg);
    color: var(--matchTextStyle-primary-color);
    border-radius: 20px;
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -1px;

    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 5000;

    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;

    box-shadow: 0 20px 40px -10px var(--matchTextStyle-border-color);

    /* Triggers our beautiful pop-and-fade animation */
    animation: matchAnimate 1.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

@keyframes matchAnimate {
    0% {
        opacity: 0;
        transform: translate(-50%, -30%) scale(0.7);
    }

    15% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1.05);
    }

    20% {
        transform: translate(-50%, -50%) scale(1);
    }

    80% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }

    100% {
        opacity: 0;
        transform: translate(-50%, -70%) scale(0.9);
    }
}