:root {
    /* Font Family Variables */
    --font-primary: 'Segoe UI', sans-serif;
    /* Updated font */
    --font-secondary: 'Zen Maru Gothic', sans-serif;
    --font-tertiary: 'ZCOOL KuaiLe', cursive;
    --font-system: system-ui, -apple-system, sans-serif;

    /* Font Weights */
    --font-weight-light: 300;
    --font-weight-regular: 400;
    --font-weight-bold: 700;

    /* Font Sizes */
    --font-size-xs: 0.75rem;
    --font-size-s: .9rem;
    --font-size-sm: 1rem;
    --font-size-base: 1.25rem;
    --font-size-md: 1.5rem;
    --font-size-lg: 2rem;
    --font-size-xl: 2.5rem;
    --font-size-xxl: 2.75rem;
    --font-size-xxxl: 3.5rem;
    --font-size-xxxxl: 4rem;

    /* Colors */
    --primary-color: #f1c40f;
    --secondary-color: #7f8c8d;
    --success-color: #75a18c;
    --target-color: #75a18c;
    --danger-color: #de9896;
    --highlight-color: #FFBF00;
    --text-color: #2c3e50;
    --background-color: #fdf6e3;
    /* Lighter background */
    --card-background: #ffe066;
    /* Yellow background for cards */
    --border-color: #4d4a60;
    --navy-blue: #000080;
    /* Defined navy blue variable */
    --dark-navy-blue: #000066;
    /* Defined dark navy blue variable */
    --level-button-color: #1a3c6e;


    /* Button styles */
    --button-default-background: var(--primary-color);
    --button-default-hover-background: #2980b9;
    --button-border-radius: 50%;
    --button-padding-vertical: 0.75rem;
    --button-padding-horizontal: 1.5rem;
    --button-font-size: 1rem;
    --button-box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
}

body {
    font-family: var(--font-primary);
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    flex-direction: column; /* Stack children vertically */
    padding-top: 200px; /* 你可以根据需要调整这个值，例如 30px 或 2rem */
    /* 如果页面内容会超过屏幕高度，确保滚动正常 */
    box-sizing: border-box; /* 确保 padding 不会增加 body 的总高度超出 100vh */
}

/* --- content-pusher 样式 --- */
.content-pusher {
    flex-grow: 1; /* 这个 div 会尽可能地增长，占据所有剩余空间 */
    /* background-color: lightgray; /* 调试时可以添加，看它是否在工作 */ */
}



/* Footer Styles */
/* Simplified Low-key Footer Styles */
 /* Footer */
.site-footer-simplified {
    width: 100%;
    background-color: var(--text-color); /* Dark footer */
    color: var(--background-color);
    text-align: center;
    padding: 30px 0;
    font-size: 14px;
    margin-top: 50px;
}

.footer-links-inline {
    margin-bottom: 15px;
}

.footer-link-inline {
    color: var(--background-color);
    text-decoration: none;
    margin: 0 10px;
    transition: opacity 0.3s ease;
}

.footer-link-inline:hover {
    opacity: 0.8;
}

.separator {
    color: rgba(255, 255, 255, 0.5);
}

.footer-info-inline p {
    margin: 0;
}

.footer-link-image {
    display: inline-block;
    margin-left: 5px;
    vertical-align: middle;
}

.email-icon {
    width: 20px;
    height: 20px;
    filter: invert(1); /* Makes the icon white for dark background */
}


.language-buttons {
    display: flex;
    gap: 8px;
    margin-top: 5px;
    /* Adjust spacing from level button */
}

.language-btn {
    font-size: .9em;
    border-radius: 30%;
    justify-content: center;
    background-color: var(--background-color);
    color: #1a3c6e;
    border: none;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    cursor: pointer;
}

.language-btn.selected {
    color: white;
    background-color: #1a3c6e;
    border: white;
    box-shadow: 0 2px 6px rgba(241, 196, 15, 0.3);
    /* Highlighted shadow */
}


.game-wrapper {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.grid-operators {
    display: flex;
    gap: 30px;
}

.word-grid {
    position: relative;
    display: grid;
    grid-template-columns: repeat(2, 100px);
    grid-template-rows: repeat(2, 100px);
    gap: 10px;
}

.word-box {
    background-color: var(--card-background);
    color: var(--level-button-color);
    font-weight: var(--font-weight-bold);
    font-size: var(--font-size-lg);
    display: flex;
    width: 100px;
    /* Fixe width */
    height: 100px;
    /* Fixed height (same as width for square) */
    justify-content: center;
    align-items: center;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    word-break: break-word;
    text-align: center;

}

.word-box:hover {
    transform: translateY(-1px);
    /* Subtle lift on hover */
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.1);
}

.word-box.selected {
    background-color: var(--highlight-color);
    border-color: var(--highlight-color);
    color: white;
    box-shadow: 0 2px 6px rgba(241, 196, 15, 0.3);
    /* Highlighted shadow */
}

.word-box.empty {
    visibility: hidden;
}

.operators {
    display: flex;
    flex-direction: column;
    gap: 20px;
    justify-content: center;
}


.operator {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    font-size: 1.5em;
    background-color: var(--level-button-color);
    color: white;
    border: none;
    cursor: pointer;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.15);
}

.operator:hover {
    background-color: var(--button-default-hover-background);
}

.operator.selected {
    background-color: var(--highlight-color);
    border-color: var(--highlight-color);
    color: white;
    box-shadow: 0 2px 6px rgba(241, 196, 15, 0.3);
    /* Highlighted shadow */
}

.target-display {
    background-color: var(--card-background);
    color: var(--level-button-color);
    padding: 10px 30px;
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
    border-radius: 5px;
}

.target-word {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
    color: var(--level-button-color);
}

.control-buttons {
    display: flex;
    gap: 10px;
}

.btn {
    padding: 10px 20px;
    border-radius: 20px;
    background-color: #ddd;
    border: none;
    cursor: pointer;
    /*font-weight: bold;*/
    color: var(--level-button-color);
}

.btn:hover {
    background-color: #ccc;
}

.level-btn {
    background-color: var(--level-button-color);
    color: white;
    border-radius: 25px;
    padding: 12px 40px;
    font-size: var(--font-size-base);
}

.level-btn:hover {
    background-color: #294b85;
}


@keyframes pulseTitle {
    0% {
        transform: scale(1);
        opacity: 1;
    }

    100% {
        transform: scale(1.05);
        opacity: 0.9;
    }
}

.sliding-word {
    position: relative;
    transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    z-index: 100;
    background-color: var(--highlight-color);
    border: 3px solid var(--highlight-color);
    border-radius: 6px;
    padding: 0.8rem;
    display: flex;
    align-items: center;
    justify-content: center;
    word-break: break-word;
    text-align: center;
    box-sizing: border-box;
    pointer-events: none;
    box-shadow: 0 3px 8px rgba(241, 196, 15, 0.5);
}

.merge-effect {
    animation: pulse 0.5s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

/* Popup styling */
/* General Popup Styling */
.popup-container,
.solution-popup {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1000;
    /* Ensure both are above other content */
    justify-content: center;
    align-items: center;
    font-family: var(--font-primary);
}

.popup-container {
    background-color: rgba(44, 62, 80, 0.85);
    /* Dark blue overlay */
}

/* Popup Content */
.popup-content,
.solution-container {
    background-color: var(--background-color);
    padding: 2rem;
    border-radius: 12px;
    /* Rounded corners */
    max-width: 600px;
    width: 90%;
    max-height: 85vh;
    overflow-y: auto;
    position: relative;
    border: 3px solid var(--primary-color);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
    color: var(--text-color);
    max-width: 500px;
    animation: popIn 0.3s cubic-bezier(0.18, 0.89, 0.32, 1.28) forwards;
}


/* Close Buttons */
.popup-close,
.solution-close {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    border: none;
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.popup-close:hover,
.solution-close:hover {
    background-color: var(--danger-color);
    transform: scale(1.1);
    /* Consistent hover effect */
    transform: rotate(90deg) scale(1.1);
    /* Unique rotate for solution close */
}

/* Popup Headers */
.popup-header,
.solution-header {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--primary-color);
    flex-direction: row;
    justify-content: space-between;
}

.popup-title,
.solution-title {
    font-size: var(--font-size-xl);
    color: var(--primary-color);
    margin: 0;
    text-align: center;
    font-weight: var(--font-weight-bold);
    text-transform: uppercase;
    letter-spacing: 1px;
    text-align: left;
}

/* Image Styling */
.rules-image {
    width: 100%;
    height: auto;
    margin: 1.5rem 0;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    background-color: white;
    padding: 8px;
}

.rules-text,
.solution-step {
    padding: 0.8rem 1rem;
    margin-bottom: 0.5rem;
    background-color: white;
    border-left: 4px solid var(--primary-color);
    border-radius: 4px;
    position: relative;
    animation: fadeIn 0.3s ease forwards;
    opacity: 0;
}

.rules-text::before {
    content: "→";
    color: var(--primary-color);
    position: absolute;
    left: -15px;
    font-weight: var(--font-weight-bold);
}

.solution-step:nth-child(1) {
    animation-delay: 0.1s;
}

.solution-step:nth-child(2) {
    animation-delay: 0.2s;
}

.solution-step:nth-child(3) {
    animation-delay: 0.3s;
}

.solution-step:nth-child(4) {
    animation-delay: 0.4s;
}

.solution-step::before {
    content: "→";
    color: var(--primary-color);
    position: absolute;
    left: -15px;
    font-weight: var(--font-weight-bold);
}

.solution-hint {
    font-style: italic;
    color: var(--secondary-color);
    margin-top: 1.5rem;
    text-align: center;
}

/* Animations */
@keyframes popIn {
    0% {
        transform: scale(0.8);
        opacity: 0;
    }

    100% {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes fadeIn {
    0% {
        transform: translateX(-10px);
        opacity: 0;
    }

    100% {
        transform: translateX(0);
        opacity: 1;
    }
}



/* Add to your CSS */
.win-celebration {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 2000;
    overflow: hidden;
}

.confetti-piece {
    position: absolute;
    width: 12px;
    height: 12px;
    opacity: 0;
    border-radius: 2px;
    animation: confetti-fall 3s ease-in forwards;
}

.confetti-piece.ikea-blue {
    background-color: #0058a3;
    /* IKEA blue */
}

.confetti-piece.ikea-yellow {
    background-color: #ffdb15;
    /* IKEA yellow */
}

.confetti-piece.ikea-white {
    background-color: white;
    border: 1px solid #0058a3;
}

.win-message {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: white;
    padding: 2rem 3rem;
    border-radius: 8px;
    border: 3px solid #ffdb15;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
    z-index: 2001;
    text-align: center;
    opacity: 0;
    animation: message-pop 0.5s 1s ease-out forwards;
}

.win-message h2 {
    color: #0058a3;
    font-size: var(--font-size-xxxl);
    margin: 0 0 1rem;
    font-weight: var(--font-weight-bold);
    text-transform: uppercase;
}

.win-message p {
    color: var(--text-color);
    font-size: var(--font-size-lg);
    margin: 0;
}

@keyframes confetti-fall {
    0% {
        opacity: 1;
        transform: translateY(-10px) rotate(0deg);
    }

    100% {
        opacity: 0;
        transform: translateY(100vh) rotate(720deg);
    }
}

@keyframes message-pop {
    0% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.8);
    }

    70% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1.1);
    }

    100% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
}


.level-selection-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    background-color: var(--background-color);
    box-sizing: border-box;
    width: 90%;
}



.level-header {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    position: fixed; /* Stick to the top of the page */
    top: 0;
    left: 0;
    z-index: 10; /* Ensure it stays on top of other content */
    padding: 10px 20px;
    background-color: var(--background-color); /* Match page background */
}

/* Back button styling */
#back-to-game-button {
    position: absolute;
    /* Positions the button relative to the .level-header */
    left: 20px;
    /* Aligns to the left */
    padding: 10px 15px;
    background-color: var(--level-button-color);
    /* Navy blue */
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: var(--font-size-sm);
    font-family: var(--font-primary);
}

#back-to-game-button:hover {
    background-color: #294b85;
    /* Slightly darker navy on hover */
}

/* Title styling */
.level-header h2 {
    color: var(--level-button-color);
    /* Navy blue */
    font-size: var(--font-size-xxl);
    /* Prominent font size */
    margin: 0;
    /* Removes default margin */
    text-align: center;
    font-weight: var(--font-weight-bold);
}

/* Grid layout for level tiles */
.level-grid {
    margin-top: 0;
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 10px;
    max-width: 900px;
    width: 100%;
}


/* Styling for individual level tiles (buttons) */
.level-tile {
    background-color: var(--card-background);
    color: var(--level-button-color);
    border: none;
    border-radius: 10px;
    padding: 30px;
    font-size: var(--font-size-xxxl);
    font-weight: var(--font-weight-bold);
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: transform 0.2s ease-in-out, background-color 0.2s ease-in-out;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    font-family: var(--font-primary);
}

.level-tile.completed {
    background-color: var(--completed-background-color); /* Change to a distinct color for completed levels */
    color: var(--completed-text-color); /* Update text color */
    border: 2px solid var(--completed-border-color); /* Custom border color */
    box-shadow: 0 4px 12px var(--card-background); /* Glowing shadow */
    transform: scale(1.05); /* Slight scale effect for emphasis */
    cursor: pointer; /* Ensure it's still interactive */
}

.level-tile.completed:hover {
    transform: scale(1.05); /* Keep scale effect on hover */
    background-color: var(--completed-background-color); /* Keep the same background on hover */
}

.level-tile.completed:active {
    transform: scale(1); /* Reset scaling on click */
}

.level-tile:hover {
    transform: translateY(-5px);
    /* Slight lift effect on hover */
    background-color: var(--highlight-color);
    /* Slightly darker yellow on hover */
}

.level-tile:active {
    transform: translateY(0);
    /* Resets on click */
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    /* Flatter shadow on click */
}

/* Styling for the large bottom button */
#confirm-selection-button {
    /* Assuming this would be the ID for the "Levels" button */
    padding: 15px 40px;
    background-color: var(--level-button-color);
    /* Navy blue */
    color: white;
    border: none;
    border-radius: 8px;
    font-size: var(--font-size-md);
    font-weight: var(--font-weight-bold);
    cursor: pointer;
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.3);
    /* More prominent shadow */
    transition: background-color 0.2s ease-in-out, transform 0.2s ease-in-out;
    font-family: var(--font-primary);
}

#confirm-selection-button:hover {
    background-color: #294b85;
    /* Slightly darker navy on hover */
    transform: translateY(-2px);
    /* Slight lift */
}

#confirm-selection-button:active {
    transform: translateY(0);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
}

/* Media Queries for Responsive Design */
@media (max-width: 768px) {
    body {
        padding-top: 100px; /* 你可以根据需要调整这个值，例如 30px 或 2rem */
    }

    .grid-operators {
        flex-direction: column;
        gap: 20px;
        align-items: center;
    }

    .operators {
        flex-direction: row;
        order: 1;
        /* Move operations above grid on mobile */
    }


    .control-buttons {
        flex-wrap: wrap;
        justify-content: center;
    }

    .level-btn {
        padding: 10px 30px;
    }
}

/* Responsive adjustments for level selection page */
@media (max-width: 768px) {
    body {
        padding-top: 100px; /* 你可以根据需要调整这个值，例如 30px 或 2rem */
    }

    .site-footer-simplified {
        font-size: 10px;
    }


    .level-grid {
        grid-template-columns: repeat(5, 1fr);
        /* 3 columns on smaller screens */
        padding: 0 10px;
    }

    .level-tile {
        padding: 20px;
        font-size: var(--font-size-xxl);
    }

    .level-header h2 {
        font-size: var(--font-size-xl);
    }

    #confirm-selection-button {
        font-size: var(--font-size-base);
        padding: 12px 30px;
    }
}

@media (max-width: 480px) {
    
    body {
        padding-top: 100px; /* 你可以根据需要调整这个值，例如 30px 或 2rem */
    }

    .level-grid {
        grid-template-columns: repeat(4, 1fr);
        /* 2 columns on very small screens */
    }

    .level-tile {
        font-size: var(--font-size-xl);
        padding: 15px;
    }

    .level-header h2 {
        font-size: var(--font-size-lg);
    }

    #back-to-game-button {
        left: 10px;
        font-size: var(--font-size-xs);
        padding: 8px 12px;
    }

    #confirm-selection-button {
        font-size: var(--font-size-sm);
        padding: 10px 20px;
    }
}