:root {
    --bg-color: #f0f2f5;
    --sidebar-bg: #ffffff;
    --element-bg: #e4e6eb;
    --element-border: #ced0d4;
    --header-bg: #ffffff;
    --text-color: #050505;
    --accent-color: #00a2ff;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --font: 'Source Sans 3', sans-serif;
}

body {
    font-family: var(--font);
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    overflow: hidden;
    user-select: none;
    -webkit-user-select: none;
}

#app {
    display: grid;
    grid-template-columns: 280px 1fr;
    grid-template-rows: auto 1fr;
    height: 100vh;
    grid-template-areas:
        "header header"
        "sidebar main";
}

header {
    grid-area: header;
    background-color: var(--header-bg);
    padding: 0 20px;
    border-bottom: 1px solid var(--element-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px var(--shadow-color);
    z-index: 100;
}

header h1 {
    font-size: 1.5rem;
    color: var(--text-color);
}

.controls button {
    background-color: var(--element-bg);
    border: 1px solid var(--element-border);
    padding: 8px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-family: var(--font);
    font-weight: 700;
    margin-left: 10px;
    transition: background-color 0.2s;
}

.controls button:hover {
    background-color: #d8dbe0;
}

#sidebar {
    grid-area: sidebar;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--element-border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

#sidebar-header {
    padding: 10px;
    border-bottom: 1px solid var(--element-border);
}

#sidebar-header h2 {
    margin: 0 0 10px 0;
    font-size: 1.2rem;
    text-align: center;
}

#search-bar {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
    border: 1px solid var(--element-border);
    border-radius: 6px;
    font-family: var(--font);
}

#element-list {
    overflow-y: auto;
    flex-grow: 1;
    padding: 10px;
}

.sidebar-element {
    padding: 10px;
    margin-bottom: 8px;
    background-color: var(--element-bg);
    border-radius: 8px;
    cursor: grab;
    text-align: center;
    font-weight: 700;
    transition: background-color 0.2s, transform 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.sidebar-element:hover {
    background-color: #d8dbe0;
    transform: scale(1.02);
}

.sidebar-element img {
    width: 20px;
    height: 20px;
    pointer-events: none;
}


#game-area {
    grid-area: main;
    position: relative;
    overflow: hidden;
    background-image:
        linear-gradient(rgba(0, 162, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 162, 255, 0.05) 1px, transparent 1px);
    background-size: 20px 20px;
}

#welcome-message {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    color: #65676b;
    font-size: 1.2rem;
}


.element {
    position: absolute;
    min-width: 100px;
    padding: 12px 18px;
    background-color: var(--sidebar-bg);
    border: 1px solid var(--element-border);
    border-radius: 8px;
    box-shadow: 0 4px 8px var(--shadow-color);
    cursor: grab;
    text-align: center;
    font-weight: 700;
    z-index: 10;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.element img {
    width: 24px;
    height: 24px;
    pointer-events: none;
}

.element.dragging {
    cursor: grabbing;
    z-index: 20;
    transform: scale(1.05);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.element.combine-hint {
    transform: scale(1.1);
    border-color: var(--accent-color);
    box-shadow: 0 0 10px var(--accent-color);
}

#toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    padding: 12px 24px;
    background-color: rgba(0, 0, 0, 0.8);
    color: white;
    border-radius: 20px;
    z-index: 1000;
    font-weight: 700;
    opacity: 1;
    transition: opacity 0.5s, bottom 0.5s;
}

#toast.hidden {
    opacity: 0;
    bottom: -50px;
    pointer-events: none;
}