:root {
    --bg-gradient-start: #ff9a9e;
    --bg-gradient-end: #fad0c4;
    --glass-bg: rgba(255, 255, 255, 0.25);
    --glass-border: rgba(255, 255, 255, 0.18);
    --glass-shadow: rgba(31, 38, 135, 0.37);
    --primary-pink: #ff6b9d;
    --secondary-pink: #ff8fab;
    --accent-purple: #c44569;
    --text-dark: #2d3436;
    --text-light: #636e72;
    --success-green: #00b894;
    --warning-orange: #fdcb6e;
    
    --cell-size: 56px;
    --target-cell-size: 28px;
    --cell-gap: 2px;
    --board-padding: 8px;
    --board-size: calc(8 * var(--cell-size) + 7 * var(--cell-gap) + 2 * var(--board-padding));
    --target-board-size: calc(8 * var(--target-cell-size) + 7 * var(--cell-gap) + 2 * var(--board-padding));
    --controls-panel-width: 240px;
    --section-padding: 1.5rem;
    --total-board-width: calc(var(--board-size) + 2 * var(--section-padding));
    --total-target-width: calc(var(--target-board-size) + 2 * var(--section-padding));
    --total-controls-width: calc(var(--controls-panel-width) + 2 * var(--section-padding));
    --min-required-width: calc(var(--total-board-width) + var(--total-controls-width) + var(--total-target-width) + 6rem);
    --border-radius: 20px;
    --shadow-soft: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
    --shadow-hover: 0 12px 40px 0 rgba(31, 38, 135, 0.5);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    min-height: 100vh;
    color: var(--text-dark);
    overflow-x: auto;
}

/* 防止布局溢出的安全措施 */
.current-board-section,
.target-board-section,
.controls-panel {
    box-sizing: border-box;
    overflow: hidden;
}

/* 确保游戏区域不会超出视口 */
.game-area {
    position: relative;
    box-sizing: border-box;
}

.app {
    min-height: 100vh;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.title-bar {
    text-align: center;
    margin-bottom: 2rem;
}

.title-bar h1 {
    font-size: 2.5rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--primary-pink);
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-light);
    font-weight: 300;
}

.game-area {
    display: grid;
    grid-template-columns: var(--total-board-width) var(--controls-panel-width) var(--total-target-width);
    gap: 3rem;
    align-items: start;
    max-width: calc(var(--min-required-width) + 4rem);
    width: 100%;
    justify-content: center;
    padding: 0 2rem;
    margin: 0 auto;
    min-width: var(--min-required-width);
}

.current-board-section,
.target-board-section {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: var(--section-padding);
    box-shadow: var(--shadow-soft);
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    box-sizing: border-box;
}

.current-board-section {
    justify-self: end;
}

.target-board-section {
    justify-self: start;
}

.current-board-section h2,
.target-board-section h2 {
    text-align: center;
    margin-bottom: 0.75rem;
    color: var(--text-dark);
    font-weight: 600;
    font-size: 1.1rem;
}

.board-container {
    display: grid;
    gap: var(--cell-gap);
    background: rgba(0, 0, 0, 0.1);
    border-radius: 10px;
    padding: var(--board-padding);
    width: fit-content;
    height: fit-content;
    margin: 0 auto;
}

[data-board="current"] {
    grid-template-columns: repeat(8, var(--cell-size));
    grid-template-rows: repeat(8, var(--cell-size));
    width: var(--board-size);
    height: var(--board-size);
}

[data-board="target"] {
    grid-template-columns: repeat(8, var(--target-cell-size));
    grid-template-rows: repeat(8, var(--target-cell-size));
    width: var(--target-board-size);
    height: var(--target-board-size);
}

.cell {
    background: rgba(255, 255, 255, 0.8);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
    width: 100%;
    height: 100%;
}

.paint-drop {
    width: 80%;
    height: 80%;
    border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
    animation: float 3s ease-in-out infinite;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.paint-drop.orange {
    background: radial-gradient(circle at 30% 30%, #ffa726, #ff9800);
}

.paint-drop.green {
    background: radial-gradient(circle at 30% 30%, #66bb6a, #4caf50);
}

.paint-drop.purple {
    background: radial-gradient(circle at 30% 30%, #ab47bc, #9c27b0);
}

.paint-drop.yellow {
    background: radial-gradient(circle at 30% 30%, #ffee58, #ffeb3b);
}

.paint-drop.pink {
    background: radial-gradient(circle at 30% 30%, #f06292, #e91e63);
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-3px); }
}

.controls-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: var(--section-padding);
    box-shadow: var(--shadow-soft);
    display: flex;
    flex-direction: column;
    gap: 1rem;
    width: var(--controls-panel-width);
    min-width: var(--controls-panel-width);
    max-width: var(--controls-panel-width);
    align-self: start;
}

.difficulty-selector {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.difficulty-selector label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    padding: 0.4rem;
    border-radius: 8px;
    transition: background-color 0.3s;
    font-size: 0.9rem;
}

.difficulty-selector label:hover {
    background: rgba(255, 255, 255, 0.2);
}

.action-buttons,
.utility-buttons {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.action-btn,
.utility-btn,
.solution-btn {
    padding: 0.6rem 1rem;
    border: none;
    border-radius: 10px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
}

.action-btn {
    background: linear-gradient(135deg, var(--primary-pink), var(--secondary-pink));
    color: white;
    box-shadow: 0 4px 15px rgba(255, 107, 157, 0.4);
}

.action-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 107, 157, 0.6);
}

.action-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.utility-btn {
    background: rgba(255, 255, 255, 0.3);
    color: var(--text-dark);
    border: 1px solid rgba(255, 255, 255, 0.5);
}

.utility-btn:hover {
    background: rgba(255, 255, 255, 0.5);
}

.solution-btn {
    background: rgba(255, 255, 255, 0.2);
    color: var(--text-dark);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.solution-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-top: 1rem;
    box-shadow: var(--shadow-soft);
    max-width: 600px;
    width: 100%;
}

.solution-steps {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.solution-steps li {
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    font-size: 0.9rem;
}

.status-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: 1rem 1.5rem;
    margin-top: 1rem;
    box-shadow: var(--shadow-soft);
    max-width: 800px;
    width: 100%;
}

.celebration-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.celebration-message {
    background: white;
    padding: 3rem;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.celebration-message h2 {
    color: var(--primary-pink);
    font-size: 2rem;
    margin-bottom: 1rem;
}

.firework {
    position: absolute;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    animation: firework 1s ease-out forwards;
}

@keyframes firework {
    0% {
        transform: translateY(0) scale(1);
        opacity: 1;
    }
    100% {
        transform: translateY(-100vh) scale(0);
        opacity: 0;
    }
}

@media (max-width: 1400px) {
    :root {
        --cell-size: 48px;
        --target-cell-size: 24px;
        --controls-panel-width: 200px;
        --board-size: calc(8 * var(--cell-size) + 7 * var(--cell-gap) + 2 * var(--board-padding));
        --target-board-size: calc(8 * var(--target-cell-size) + 7 * var(--cell-gap) + 2 * var(--board-padding));
    }
    
    .game-area {
        gap: 2rem;
        padding: 0 1rem;
    }
}

@media (max-width: 1250px) {
    .game-area {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto auto;
        gap: 2rem;
        justify-items: center;
        max-width: 100%;
        padding: 0 2rem;
        min-width: auto;
    }
    
    .current-board-section,
    .target-board-section {
        width: fit-content;
        justify-self: center;
    }
    
    .controls-panel {
        order: 2;
        width: 100%;
        max-width: min(600px, 90vw);
        min-width: auto;
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 1.5rem;
        align-items: start;
    }
    
    .difficulty-selector,
    .action-buttons,
    .utility-buttons {
        display: flex;
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .solution-btn {
        grid-column: 1 / -1;
    }
    
    .target-board-section {
        order: 3;
    }
}

@media (max-width: 768px) {
    .app {
        padding: 1rem;
    }
    
    :root {
        --board-size: 400px;
        --cell-size: 50px;
        --target-board-size: 200px;
        --target-cell-size: 25px;
    }
    
    .game-area {
        gap: 1.5rem;
        padding: 0 1rem;
    }
    
    .controls-panel {
        grid-template-columns: 1fr;
        gap: 1rem;
        padding: 1.2rem;
    }
    
    .solution-btn {
        grid-column: 1;
    }
}

@media (max-width: 480px) {
    :root {
        --board-size: 320px;
        --cell-size: 40px;
        --target-board-size: 160px;
        --target-cell-size: 20px;
    }
    
    .app {
        padding: 0.5rem;
    }
    
    .game-area {
        gap: 1rem;
        padding: 0 0.5rem;
    }
    
    .controls-panel {
        width: 100%;
        max-width: var(--board-size);
        min-width: auto;
        padding: 1rem;
        grid-template-columns: 1fr;
    }
    
    .current-board-section,
    .target-board-section {
        padding: 1rem;
    }
    
    .title-bar h1 {
        font-size: 1.8rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
}