/* 24点挑战 - 科技感视觉重构 */

:root {
    --neon-blue: #00f3ff;
    --neon-pink: #ff00ff;
    --neon-green: #39ff14;
    --bg-dark: #0a0b1e;
    --card-glass: rgba(255, 255, 255, 0.05);
    --border-glass: rgba(255, 255, 255, 0.1);
    --text-glow: 0 0 10px var(--neon-blue);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: 'Orbitron', 'Segoe UI', sans-serif;
    background: var(--bg-dark);
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(0, 243, 255, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(255, 0, 255, 0.05) 0%, transparent 50%);
    color: #fff;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
    padding: 20px;
}

/* 游戏容器 */
.game-container {
    width: 100%;
    max-width: 400px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    z-index: 1;
}

/* 顶部信息栏 */
header {
    text-align: center;
    margin-bottom: 5px;
}

h1 {
    font-size: 2rem;
    letter-spacing: 4px;
    color: var(--neon-blue);
    text-shadow: var(--text-glow);
    margin-bottom: 10px;
    text-transform: uppercase;
}

.stats {
    display: flex;
    justify-content: space-between;
    font-size: 1rem;
    background: var(--card-glass);
    backdrop-filter: blur(10px);
    padding: 12px 20px;
    border-radius: 30px;
    border: 1px solid var(--border-glass);
    box-shadow: 0 0 20px rgba(0, 243, 255, 0.1);
}

#timer-val { color: var(--neon-pink); text-shadow: 0 0 10px var(--neon-pink); }
#level-val { color: var(--neon-green); text-shadow: 0 0 10px var(--neon-green); }

/* 数字卡片区域 */
.number-area {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.num-btn {
    aspect-ratio: 1 / 1;
    background: var(--card-glass);
    backdrop-filter: blur(5px);
    border: 1px solid var(--neon-blue);
    border-radius: 15px;
    font-size: 3rem;
    font-weight: bold;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: inset 0 0 15px rgba(0, 243, 255, 0.1);
    position: relative;
    overflow: hidden;
}

.num-btn::after {
    content: '';
    position: absolute;
    top: -50%; left: -50%; width: 200%; height: 200%;
    background: linear-gradient(45deg, transparent, rgba(255,255,255,0.1), transparent);
    transform: rotate(45deg);
    transition: 0.5s;
}

.num-btn:active {
    transform: scale(0.95);
    background: rgba(0, 243, 255, 0.2);
}

.num-btn.disabled {
    opacity: 0.3;
    border-color: #444;
    pointer-events: none;
    filter: grayscale(1);
}

/* 表达式显示区 */
.display-area {
    background: rgba(0, 0, 0, 0.3);
    min-height: 70px;
    border-radius: 15px;
    padding: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--neon-blue);
    border: 1px solid var(--border-glass);
    box-shadow: inset 0 0 20px rgba(0, 0, 0, 0.5);
    font-family: 'Courier New', monospace;
    letter-spacing: 2px;
}

/* 运算符区域 */
.operator-area {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.op-btn {
    background: var(--card-glass);
    color: #fff;
    border: 1px solid var(--border-glass);
    border-radius: 10px;
    padding: 12px 0;
    font-size: 1.4rem;
    cursor: pointer;
    transition: 0.2s;
}

.op-btn:active {
    background: var(--neon-blue);
    color: var(--bg-dark);
    box-shadow: 0 0 15px var(--neon-blue);
}

/* 控制按钮区域 */
.control-area {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 10px;
}

.ctrl-btn {
    padding: 12px 0;
    border-radius: 10px;
    border: 1px solid var(--border-glass);
    background: var(--card-glass);
    color: #fff;
    font-size: 0.9rem;
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 1px;
}

#btn-submit {
    grid-column: span 3;
    background: linear-gradient(90deg, var(--neon-blue), var(--neon-pink));
    border: none;
    font-weight: bold;
    font-size: 1.2rem;
    padding: 15px;
    margin-top: 5px;
    box-shadow: 0 0 20px rgba(0, 243, 255, 0.3);
}

#btn-submit:active { transform: scale(0.98); opacity: 0.8; }

/* 全屏遮罩层 (引导、成功、提示) */
.overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(10, 11, 30, 0.95);
    backdrop-filter: blur(15px);
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 30px;
    text-align: center;
}

.overlay-content {
    max-width: 320px;
    animation: slideUp 0.5s ease-out;
}

@keyframes slideUp {
    from { transform: translateY(50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.overlay h2 {
    font-size: 2.5rem;
    color: var(--neon-blue);
    margin-bottom: 20px;
    text-shadow: var(--text-glow);
}

.overlay p {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 30px;
    color: #ccc;
}

.main-btn {
    background: transparent;
    border: 2px solid var(--neon-blue);
    color: var(--neon-blue);
    padding: 15px 40px;
    font-size: 1.2rem;
    border-radius: 30px;
    cursor: pointer;
    font-weight: bold;
    text-transform: uppercase;
    transition: 0.3s;
    box-shadow: 0 0 15px rgba(0, 243, 255, 0.2);
    margin: 10px;
}

.main-btn:hover, .main-btn:active {
    background: var(--neon-blue);
    color: var(--bg-dark);
    box-shadow: 0 0 30px var(--neon-blue);
}

.highlight { color: var(--neon-green); font-size: 1.5rem; font-weight: bold; }

/* Toast */
#toast {
    position: fixed;
    top: 20%;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(255, 0, 255, 0.2);
    border: 1px solid var(--neon-pink);
    color: #fff;
    padding: 10px 25px;
    border-radius: 20px;
    backdrop-filter: blur(5px);
    opacity: 0;
    transition: 0.3s;
    z-index: 2000;
}

#toast.show { opacity: 1; top: 25%; }

/* 粒子效果 */
.particle {
    position: absolute;
    width: 4px; height: 4px;
    border-radius: 50%;
    pointer-events: none;
    animation: explode 2s ease-out forwards;
}

@keyframes explode {
    to { transform: translate(var(--tx), var(--ty)); opacity: 0; }
}

/* 引导页特殊样式 */
#intro-overlay { display: flex; }
.rule-list { text-align: left; margin-bottom: 30px; font-size: 0.9rem; color: #aaa; }
.rule-list li { margin-bottom: 10px; }