:root {
    --bg-color: #f0f4f8;
    --wood-texture: url('wood_texture.png');
    --board-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
    --slot-depth: inset 2px 2px 5px rgba(0, 0, 0, 0.4), inset -1px -1px 2px rgba(255, 255, 255, 0.3);
    --block-color: #3b82f6;
    /* Default blue */
    --block-size: 50px;
    --block-shadow: 2px 4px 6px rgba(0, 0, 0, 0.3), inset 2px 2px 5px rgba(255, 255, 255, 0.4), inset -2px -2px 5px rgba(0, 0, 0, 0.1);
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Fredoka', sans-serif;
    background-color: var(--bg-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: #333;
    overflow: hidden;
    /* Prevent scrolling if possible */
}

.app-container {
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100vh;
    /* Fallback */
    height: 100dvh;
    /* Mobile viewport fix */
    max-width: 1200px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    z-index: 10;
}

h1 {
    margin: 0;
    font-size: 1.5rem;
    color: #4a5568;
}

button {
    background: white;
    border: 1px solid #ccc;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    font-weight: 600;
    transition: all 0.2s;
}

button:hover {
    background: #f7fafc;
    transform: translateY(-1px);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

main {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    gap: 0.5rem;
    overflow: hidden;
}

.board-container {
    background-image: var(--wood-texture);
    background-size: cover;
    background-repeat: repeat;
    padding: 1rem;
    border-radius: 12px;
    box-shadow: var(--board-shadow);
    display: flex;
    justify-content: center;
    align-items: flex-end;
    /* Flexible height to accommodate growing content */
    flex: 1;
    min-height: 0;
    overflow: hidden;
    /* Prevent scrolling as requested */
    width: 95%;
    position: relative;
    /* For absolute positioning context if needed */
}

.board {
    display: flex;
    gap: 1.5rem;
    align-items: flex-end;
    align-items: flex-end;
    /* margin: auto; Removed to allow correct centering via flex parent */
    /* Centers content when it fits, allows scroll when it doesn't */
    padding-bottom: 20px;
    /* Space for scrollbar */
    transform-origin: bottom center;
    /* Scale from bottom center */
    transition: transform 0.3s ease-out;
    /* Smooth scaling */
    flex-wrap: nowrap;
    width: max-content;
    /* Ensure it takes full width for measurement */
    max-width: none;
    /* Allow exceeding container */
}

.column {
    display: flex;
    flex-direction: column-reverse;
    /* Stack from bottom up */
    align-items: center;
    gap: 10px;
}

/* The slots/holes on the board */
.slot {
    width: var(--block-size);
    height: var(--block-size);
    border-radius: 50%;
    background-color: rgba(60, 40, 20, 0.2);
    box-shadow: var(--slot-depth);
    position: relative;
    /* For placing blocks inside */
    transition: width 0.3s, height 0.3s, background-color 0.2s;
}

.slot.hovered {
    background-color: rgba(60, 40, 20, 0.5);
    /* Darker/clearer interaction state */
    box-shadow: inset 0 0 10px rgba(255, 255, 255, 0.5);
    /* Inner glow */
    border: 2px solid #fff;
}

/* The label/tile at the bottom */
.column-label {
    margin-top: 15px;
    /* Because of column-reverse, this is actually usually at the "end" of the flex container logically, but visually at bottom. Wait. 
       If flex-direction is column-reverse, the first child is at the bottom.
       Let's use column-reverse for the slots wrapper, OR just use normal column and justify-content: flex-end. 
       Let's stick to normal column for simplicity and just reverse the order of rendering slots if needed, or justify-end.
    */
}

/* Actually, let's restructure the column slightly in JS/HTML to make it easier.
   Container -> Slots (flex-col-reverse)
             -> Label
   Wait, label matches column. 
*/
.col-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex-shrink: 0;
    /* Prevent squashing when many columns */
}

.slots-container {
    display: flex;
    flex-direction: column-reverse;
    /* 1 at bottom, N at top */
    gap: 8px;
    padding-bottom: 10px;
}

.number-tile {
    width: calc(var(--block-size) * 1.2);
    height: calc(var(--block-size) * 1.2);
    background: #fdfdfd;
    border: 1px solid #d1d5db;
    border-radius: 4px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: bold;
    color: #1f2937;
    box-shadow: 2px 2px 5px rgba(0, 0, 0, 0.1);
    user-select: none;
}

/* The Block */
.block {
    width: var(--block-size);
    height: var(--block-size);
    background-color: var(--block-color);
    border-radius: 50%;
    box-shadow: var(--block-shadow);
    cursor: grab;
    position: relative;
    /* relative to slot */
    z-index: 2;
    transition: transform 0.1s;
}

.block:active {
    cursor: grabbing;
    transform: scale(0.95);
}

/* Tray Area */
.tray-container {
    width: 90%;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 12px;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.tray-container h2 {
    margin: 0 0 10px 0;
    font-size: 1rem;
    color: #666;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.tray {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(var(--block-size) + 20px);
    width: 100%;
}

.source-block {
    /* The infinite source block */
    width: var(--block-size);
    height: var(--block-size);
    background-color: var(--block-color);
    border-radius: 50%;
    box-shadow: var(--block-shadow);
    cursor: grab;
    transition: transform 0.2s;
    touch-action: none;
    /* Prevent scrolling on touch */
}

.source-block:hover {
    transform: scale(1.1);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    opacity: 1;
    transition: opacity 0.3s;
}

.modal.hidden {
    opacity: 0;
    pointer-events: none;
}

.modal-content {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    width: 90%;
    max-width: 400px;
    position: relative;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.close {
    position: absolute;
    top: 10px;
    right: 15px;
    font-size: 1.5rem;
    cursor: pointer;
    color: #aaa;
}

.close:hover {
    color: #333;
}

.setting-group {
    margin-bottom: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.setting-group label {
    font-weight: 600;
    color: #444;
}

.setting-group input[type="range"] {
    width: 100%;
}

.setting-group input[type="color"] {
    width: 100px;
    height: 40px;
    border: none;
    cursor: pointer;
}

/* Animation for dropping */
@keyframes popIn {
    0% {
        transform: scale(0);
        opacity: 0;
    }

    80% {
        transform: scale(1.1);
        opacity: 1;
    }

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

.block.placed {
    animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* Visibility classes */
.invisible {
    visibility: hidden;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.5s;
}

/* Maru (Circle) for columns */
.maru-mark {
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%) scale(0);
    width: 80%;
    height: auto;
    pointer-events: none;
    z-index: 5;
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.maru-mark.show {
    transform: translateX(-50%) scale(1);
}

.col-wrapper {
    position: relative;
    /* For positioning the Maru */
}

/* Victory Overlay */
.victory-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(255, 255, 255, 0.85);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 50;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.5s;
}

.victory-overlay.show {
    opacity: 1;
    pointer-events: all;
}

.hanamaru {
    width: 300px;
    height: 300px;
    object-fit: contain;
    animation: spinIn 0.8s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes spinIn {
    0% {
        transform: scale(0) rotate(-180deg);
        opacity: 0;
    }

    100% {
        transform: scale(1) rotate(0deg);
        opacity: 1;
    }
}

.reset-btn {
    margin-top: 2rem;
    padding: 1rem 3rem;
    font-size: 1.5rem;
    background: #FF5722;
    color: white;
    border: none;
    border-radius: 50px;
    box-shadow: 0 4px 15px rgba(255, 87, 34, 0.4);
    cursor: pointer;
    animation: bounce 2s infinite;
}

.reset-btn:hover {
    background: #F4511E;
    transform: scale(1.05);
}

@keyframes bounce {

    0%,
    20%,
    50%,
    80%,
    100% {
        transform: translateY(0);
    }

    40% {
        transform: translateY(-10px);
    }

    60% {
        transform: translateY(-5px);
    }
}