/* Base Styles */
:root {
    /* Primary Colors */
    --primary-color: #007AFF;
    --primary-light: #4DA2FF;
    --primary-dark: #0056CC;
    
    /* Accent Colors */
    --accent-color: #FF6B35;
    --accent-light: #FF8A65;
    --accent-dark: #E55100;
    
    /* Neutral Colors */
    --text-color: #1D1D1F;
    --text-light: #86868B;
    --text-lighter: #A1A1A6;
    --background-color: #FBFBFD;
    --surface-color: #FFFFFF;
    
    /* Game Colors */
    --cell-color: #ffffff;
    --fixed-cell-color: #F2F2F7;
    --border-color: #D1D1D6;
    --highlight-color: rgba(0, 122, 255, 0.1);
    
    /* Status Colors */
    --error-color: #FF3B30;
    --error-bg: #FFEBEE;
    --success-color: #34C759;
    --success-bg: #E8F5E8;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 25px rgba(0, 0, 0, 0.15);
    
    /* Transitions */
    --transition-fast: 0.2s;
    --transition-normal: 0.3s;
    --transition-slow: 0.5s;
    
    /* Layout */
    --max-width: 1200px;
    --section-padding: 30px 0;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    scroll-behavior: smooth;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all var(--transition-normal);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    max-width: var(--max-width);
    margin: 0 auto;
}

.nav-brand .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav-links a:hover {
    color: var(--primary-color);
}

.cta-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.cta-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-color);
    margin: 3px 0;
    transition: var(--transition-fast);
}

/* Hero Section */
.hero {
    padding: 100px 0 60px;
    text-align: center;
    background: linear-gradient(135deg, var(--background-color) 0%, #F0F8FF 100%);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 20px;
    line-height: 1.1;
}

.highlight {
    color: var(--primary-color);
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-light);
    margin-bottom: 32px;
    line-height: 1.5;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 48px;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 16px 32px;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: transparent;
    color: var(--text-color);
    border: 2px solid var(--border-color);
    padding: 14px 32px;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Section Styles */
.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 48px;
    color: var(--text-color);
}

/* Features Section */
.features {
    padding: var(--section-padding);
    background: var(--surface-color);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
}

.feature-card {
    text-align: center;
    padding: 32px 20px;
    border-radius: 16px;
    background: var(--background-color);
    transition: transform var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-4px);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-color);
}

.feature-card p {
    color: var(--text-light);
    line-height: 1.6;
}

/* How It Works Section */
.how-it-works {
    padding: var(--section-padding);
    background: var(--background-color);
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.step {
    text-align: center;
    padding: 32px 20px;
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 24px;
}

.step h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-color);
}

.step p {
    color: var(--text-light);
    line-height: 1.6;
}

/* Game Section */
.game-section {
    padding: var(--section-padding);
    background: var(--surface-color);
}

.game-container {
    max-width: 600px;
    margin: 0 auto;
    padding: 32px;
    background: var(--surface-color);
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
    padding: 10px;
    background: var(--background-color);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.game-board-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

/* Sudoku Board */
.sudoku-board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    grid-gap: 1px;
    background-color: var(--border-color);
    border: 3px solid var(--primary-color);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    width: 420px;
    height: 420px;
    position: relative;
}

.sudoku-board::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.1);
    pointer-events: none;
    z-index: 1;
}

.cell {
    aspect-ratio: 1;
    background-color: var(--cell-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal) ease;
    position: relative;
    color: var(--text-color);
}

.cell:hover {
    background-color: var(--highlight-color);
}

.cell:active {
    transform: scale(0.98);
}

.cell.fixed {
    background-color: var(--fixed-cell-color);
    font-weight: 700;
    color: var(--primary-dark);
}

.cell.highlighted {
    background-color: var(--highlight-color);
}

.cell.error {
    background-color: var(--error-bg);
    color: var(--error-color);
    font-weight: 600;
    animation: pulse 0.5s ease-in-out 2;
}

.cell.solution {
    background-color: var(--success-bg);
    color: var(--success-color);
    font-weight: 600;
    animation: fadeIn 0.5s ease-in-out;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* 加强网格线 */
.cell:nth-child(3n) {
    border-right: 2px solid var(--primary-dark);
}

.cell:nth-child(9n+1) {
    border-left: 2px solid var(--primary-dark);
}

.cell:nth-child(n+19):nth-child(-n+27),
.cell:nth-child(n+46):nth-child(-n+54) {
    border-bottom: 2px solid var(--primary-dark);
}

/* 细网格线 */
.cell {
    border-right: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

/* Controls */
.difficulty-selector {
    display: flex;
    gap: 6px;
    flex: 1;
}

.controls {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    padding: 16px;
    background: var(--background-color);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

button {
    padding: 10px 16px;
    border: none;
    border-radius: 8px;
    background: var(--primary-color);
    color: white;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

button:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}

button:active {
    transform: translateY(0);
}

.difficulty-btn {
    background: white;
    color: var(--primary-dark);
    border: 1px solid var(--border-color);
    padding: 8px 16px;
    font-weight: 600;
    font-size: 0.9rem;
    border-radius: 8px;
    transition: all var(--transition-fast);
}

.difficulty-btn:hover {
    background: var(--highlight-color);
    border-color: var(--primary-color);
}

.difficulty-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Timer */
.timer {
    font-size: 1.0rem;
    font-weight: 700;
    color: var(--primary-color);
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    padding: 2px 3px;
    border: 2px solid var(--primary-color);
    border-radius: 12px;
    background-color: white;
    box-shadow: var(--shadow-sm);
    font-family: 'JetBrains Mono', monospace;
    letter-spacing: 1px;
    min-width: 100px;
    text-align: center;
}

/* Dialog Styles */
.dialog {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 1;
    transition: opacity var(--transition-normal);
    backdrop-filter: blur(5px);
}

.dialog.hidden {
    display: none;
    opacity: 0;
}

.dialog-content {
    background-color: white;
    padding: 2.5rem;
    border-radius: 24px;
    box-shadow: var(--shadow-lg), 0 0 0 1px rgba(255, 255, 255, 0.1);
    max-width: 550px;
    width: 90%;
    max-height: 85vh;
    overflow-y: auto;
    transform: translateY(0);
    transition: transform var(--transition-normal);
    position: relative;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.dialog.hidden .dialog-content {
    transform: translateY(20px);
}

.dialog-content::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 6px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    border-radius: 24px 24px 0 0;
}

.dialog h2 {
    margin-top: 0;
    color: var(--primary-color);
    text-align: center;
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    position: relative;
}

.dialog h2::after {
    content: "";
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 3px;
    background-color: var(--accent-color);
    border-radius: 2px;
}

.dialog-buttons {
    display: flex;
    justify-content: center;
    gap: 1.2rem;
    margin-top: 2rem;
}

.dialog p {
    color: var(--text-color);
    line-height: 1.6;
    margin-bottom: 1.2rem;
    font-size: 1.05rem;
}

/* Leaderboard Styles */
.leaderboard {
    margin-top: 2.5rem;
    padding: 1.5rem;
    background-color: white;
    border-radius: 20px;
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
}

.leaderboard::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
}

.leaderboard h2 {
    text-align: center;
    margin-bottom: 1.5rem;
    color: var(--primary-dark);
    font-size: 1.8rem;
    font-weight: 700;
    position: relative;
    display: inline-block;
    width: 100%;
}

.leaderboard h2::after {
    content: "";
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 3px;
    background-color: var(--accent-color);
    border-radius: 2px;
}

.leaderboard-tabs {
    display: flex;
    justify-content: center;
    gap: 0.8rem;
    margin-bottom: 1.5rem;
    padding: 0.8rem;
    background-color: var(--fixed-cell-color);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
}

.leaderboard-tab {
    padding: 0.7rem 1.4rem;
    border-radius: 10px;
    cursor: pointer;
    font-weight: 600;
    transition: all var(--transition-fast);
    position: relative;
    z-index: 1;
    color: var(--text-color);
}

.leaderboard-tab:hover {
    color: var(--primary-color);
    background-color: rgba(255, 255, 255, 0.8);
}

.leaderboard-tab.active {
    background-color: white;
    color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.leaderboard-content {
    margin: 1.5rem 0;
    background-color: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.leaderboard-row {
    display: grid;
    grid-template-columns: 60px 1fr 100px 120px;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    align-items: center;
    transition: background-color var(--transition-fast);
}

.leaderboard-row:hover {
    background-color: var(--highlight-color);
}

.leaderboard-row.header {
    font-weight: 700;
    color: var(--primary-dark);
    border-bottom: 2px solid var(--primary-color);
    background: linear-gradient(to bottom, #f8f9fa, #e9ecef);
    padding: 1.2rem 1rem;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    font-size: 0.9rem;
}

.leaderboard-row:last-child {
    border-bottom: none;
}

.leaderboard-row .rank {
    text-align: center;
    font-weight: 700;
    color: var(--primary-dark);
    font-size: 1.1rem;
}

/* 前三名特殊样式 */
.leaderboard-row:nth-child(2) .rank {
    color: gold;
    font-size: 1.2rem;
}

.leaderboard-row:nth-child(3) .rank {
    color: silver;
    font-size: 1.15rem;
}

.leaderboard-row:nth-child(4) .rank {
    color: #cd7f32; /* 铜色 */
    font-size: 1.1rem;
}

.leaderboard-row .name {
    font-weight: 600;
    color: var(--text-color);
    padding-left: 0.5rem;
}

.leaderboard-row .time {
    text-align: center;
    font-family: 'Roboto Mono', monospace;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
}

.leaderboard-row .date {
    text-align: center;
    color: var(--text-light);
    font-size: 0.9rem;
}

.leaderboard-row.empty {
    display: block;
    text-align: center;
    padding: 2.5rem 0;
    color: var(--text-light);
    font-style: italic;
    background-color: var(--fixed-cell-color);
    border-radius: 8px;
}

.empty-message {
    text-align: center;
    width: 100%;
    font-size: 1.05rem;
}

/* Name Input Form */
#player-name {
    width: 100%;
    padding: 0.9rem 1.2rem;
    border: 2px solid var(--primary-light);
    border-radius: 12px;
    font-size: 1.05rem;
    margin: 1.2rem 0;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-sm);
    background-color: white;
    color: var(--text-color);
}

#player-name:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(58, 91, 185, 0.2);
}

#player-name::placeholder {
    color: var(--text-light);
}

.form-group {
    margin-bottom: 1.8rem;
    position: relative;
}

.form-group label {
    display: block;
    margin-bottom: 0.8rem;
    font-weight: 600;
    color: var(--primary-dark);
    font-size: 1.05rem;
    position: relative;
    padding-left: 0.5rem;
}

.form-group label::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 16px;
    background-color: var(--accent-color);
    border-radius: 2px;
}

.form-group input {
    width: 100%;
    padding: 0.9rem 1.2rem;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    font-size: 1.05rem;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-sm);
    background-color: white;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(58, 91, 185, 0.2);
}

.form-group input::placeholder {
    color: var(--text-light);
}

.name-input-message {
    background-color: var(--highlight-color);
    padding: 1rem 1.2rem;
    border-radius: 10px;
    color: var(--primary-dark);
    font-weight: 500;
    margin-bottom: 1.2rem;
    text-align: center;
    border-left: 4px solid var(--primary-color);
    line-height: 1.5;
}

/* 数字选择器 */
.number-selector {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    gap: 8px;
    width: 420px;
    padding: 16px;
    background: var(--background-color);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.number-btn {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    font-weight: 700;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--primary-dark);
    box-shadow: var(--shadow-sm);
}

.number-btn:hover {
    background: var(--highlight-color);
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.number-btn:active {
    transform: translateY(1px);
}

.number-btn.selected {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.3), var(--shadow-md);
}

/* 游戏状态信息 */
.game-status {
    text-align: center;
    padding: 6px 10px;
    border-radius: 10px;
    background: linear-gradient(135deg, var(--highlight-color), rgba(0, 122, 255, 0.05));
    color: var(--primary-dark);
    font-weight: 500;
    font-size: 1rem;
    border: 1px solid rgba(0, 122, 255, 0.2);
    transition: all var(--transition-normal);
}

.game-status.success {
    background-color: var(--success-bg);
    color: var(--success-color);
    animation: pulse 1s ease-in-out;
}

.game-status.error {
    background-color: var(--error-bg);
    color: var(--error-color);
}

/* Testimonials Section */
.testimonials {
    padding: var(--section-padding);
    background: var(--background-color);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 40px;
}

.testimonial {
    background: var(--surface-color);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.testimonial-content p {
    font-size: 1.1rem;
    line-height: 1.6;
    color: var(--text-color);
    margin-bottom: 24px;
    font-style: italic;
}

.testimonial-author strong {
    display: block;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 4px;
}

.testimonial-author span {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* FAQ Section */
.faq {
    padding: var(--section-padding);
    background: var(--surface-color);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 24px;
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 0;
    cursor: pointer;
    transition: color var(--transition-fast);
}

.faq-question:hover {
    color: var(--primary-color);
}

.faq-question h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin: 0;
}

.faq-toggle {
    font-size: 1.5rem;
    font-weight: 300;
    transition: transform var(--transition-fast);
}

.faq-item.active .faq-toggle {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-normal);
}

.faq-item.active .faq-answer {
    max-height: 200px;
    padding-bottom: 24px;
}

.faq-answer p {
    color: var(--text-light);
    line-height: 1.6;
}

/* Footer */
.footer {
    background: var(--text-color);
    color: white;
    padding: 60px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.footer-section h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-lighter);
}

.footer-section p {
    color: var(--text-lighter);
    line-height: 1.6;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section ul li a {
    color: var(--text-lighter);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-section ul li a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid #333;
    padding-top: 20px;
    text-align: center;
    color: var(--text-lighter);
}

.footer-bottom a {
    color: var(--text-lighter);
    text-decoration: none;
}

.footer-bottom a:hover {
    color: white;
}

/* 额外动画效果 */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes scaleIn {
    from { transform: scale(0.95); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.game-container {
    animation: scaleIn var(--transition-normal) ease-out;
}

.sudoku-board {
    animation: fadeIn var(--transition-normal) ease-out;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow-md);
        border-top: 1px solid var(--border-color);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-stats {
        gap: 30px;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .features-grid,
    .testimonials-grid {
        grid-template-columns: 1fr;
    }
    
    .steps {
        grid-template-columns: 1fr;
    }
    
    .game-container {
        padding: 20px;
        margin: 0 10px;
        gap: 16px;
    }
    
    .game-header {
        flex-direction: column;
        gap: 12px;
        padding: 12px;
    }
    
    .difficulty-selector {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 6px;
        width: 100%;
    }
    
    .timer {
        font-size: 1.2rem;
        padding: 8px 16px;
        min-width: 80px;
    }
    
    .sudoku-board {
        width: 350px;
        height: 350px;
        border-width: 2px;
    }
    
    .cell {
        font-size: 1.1rem;
    }
    
    .number-selector {
        width: 350px;
        gap: 6px;
        padding: 12px;
    }
    
    .controls {
        grid-template-columns: 1fr 1fr;
        gap: 8px;
        padding: 12px;
    }
    
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
        gap: 30px;
    }
    
    .leaderboard-row {
        grid-template-columns: 40px 1fr 80px 100px;
        font-size: 0.95rem;
        padding: 0.8rem;
    }
    
    .dialog-content {
        padding: 1.8rem;
        width: 95%;
    }
    
    button {
        padding: 8px 12px;
        font-size: 0.85rem;
    }
    
    .number-btn {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 20px;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
    
    .game-container {
        padding: 16px;
        margin: 0 5px;
        gap: 12px;
    }
    
    .game-header {
        padding: 10px;
    }
    
    .timer {
        font-size: 1.1rem;
        padding: 6px 12px;
    }
    
    .sudoku-board {
        width: 300px;
        height: 300px;
    }
    
    .cell {
        font-size: 1rem;
    }
    
    .number-selector {
        width: 300px;
        gap: 4px;
        padding: 10px;
    }
    
    .number-btn {
        font-size: 1rem;
    }
    
    .controls {
        grid-template-columns: 1fr;
        gap: 8px;
        padding: 10px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .leaderboard-row {
        grid-template-columns: 30px 1fr 70px 90px;
        font-size: 0.85rem;
        padding: 0.7rem 0.5rem;
    }
    
    .leaderboard-tabs {
        flex-wrap: wrap;
    }
    
    .dialog-content {
        padding: 1.5rem;
    }
    
    .dialog h2 {
        font-size: 1.5rem;
    }
    
    .leaderboard-date {
        display: none;
    }
}

/* 打印样式 */
@media print {
    .game-container {
        box-shadow: none;
        margin: 0;
        padding: 1rem;
    }
    
    .controls, .difficulty-selector, .number-selector, .footer {
        display: none;
    }
    
    .sudoku-board {
        page-break-inside: avoid;
    }
}