/* ===================================
   Reset & Base Styles
   =================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors - Xanh thiên thanh chủ đạo */
    --primary: #00BCD4;        /* Cyan/Sky Blue */
    --primary-dark: #0097A7;
    --primary-light: #4DD0E1;
    --secondary: #1CB0F6;      /* Blue */
    --secondary-dark: #0EA5E9;
    --accent: #FFCE00;         /* Yellow */
    --accent-orange: #FF9600;
    --accent-pink: #FF6B9D;
    --accent-purple: #9B59B6;
    --accent-teal: #1ABC9C;
    --white: #FFFFFF;
    --gray-50: #FAFAFA;
    --gray-100: #F5F5F5;
    --gray-200: #EEEEEE;
    --gray-300: #E0E0E0;
    --gray-600: #757575;
    --gray-800: #424242;
    --text-dark: #2C3E50;
    --text-light: #6C757D;
    
    /* Backward compatibility - Giữ các biến cũ cho các trang khác */
    --primary-blue: #00BCD4;      /* Map to primary */
    --light-blue: #4DD0E1;         /* Map to primary-light */
    --gold: #FFCE00;               /* Map to accent */
    --orange: #FF9600;             /* Map to accent-orange */
    --green: #1ABC9C;              /* Map to accent-teal */
    --red: #FF6B6B;                /* Keep red */
    --pink: #FF6B9D;               /* Map to accent-pink */
    --purple: #9B59B6;             /* Map to accent-purple */
    --dark-gray: #424242;          /* Map to gray-800 */
    --light-gray: #F5F5F5;         /* Map to gray-100 */
    
    /* Typography */
    --font-primary: 'Nunito', sans-serif;
    --font-size-base: 16px;
    --font-size-large: 24px;
    --font-size-title: 32px;
    
    /* Spacing */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-full: 50%;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 8px rgba(0,0,0,0.15);
    --shadow-lg: 0 8px 16px rgba(0,0,0,0.2);
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    color: var(--text-dark);
    background: #F8F9FA;
    min-height: 100vh;
    line-height: 1.6;
    position: relative;
    overflow-x: hidden;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 10% 20%, rgba(0, 188, 212, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 90% 80%, rgba(28, 176, 246, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(255, 206, 0, 0.03) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

body > * {
    position: relative;
    z-index: 1;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    width: 100%;
}

/* ===================================
   Header
   =================================== */
.header {
    background: var(--white);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--gray-200);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    gap: 20px;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--primary);
    text-decoration: none;
    transition: transform 0.3s ease;
    flex-shrink: 0;
}

.logo:hover {
    transform: scale(1.05);
}

.logo a {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--primary);
    text-decoration: none;
}

.logo i {
    font-size: 28px;
    flex-shrink: 0;
}

.logo h1 {
    font-size: 20px;
    font-weight: 800;
    margin: 0;
    white-space: nowrap;
    line-height: 1.2;
}

.nav {
    display: flex;
    gap: 4px;
    align-items: center;
    flex-wrap: nowrap;
    flex: 1;
    justify-content: flex-end;
    min-width: 0;
}

.nav-link {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 600;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    white-space: nowrap;
    position: relative;
    background: transparent;
    flex-shrink: 0;
}

.nav-link span {
    white-space: nowrap;
}

.nav-link i {
    font-size: 14px;
    width: 16px;
    text-align: center;
    flex-shrink: 0;
}

.nav-link:hover {
    background: rgba(0, 188, 212, 0.1);
    color: var(--primary);
    transform: translateY(-1px);
}

.nav-link.active {
    color: var(--white);
    background: var(--primary);
    box-shadow: 0 4px 12px rgba(0, 188, 212, 0.3);
}

.nav-link.active:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(0, 188, 212, 0.4);
}

.nav-link.active i {
    color: var(--white);
}

.btn-primary {
    background: var(--primary);
    color: var(--white);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-md);
}

.btn-primary:hover {
    background: var(--primary-dark);
}

/* ===================================
   Hero Section - Clean & Modern
   =================================== */
.hero {
    padding: var(--spacing-md) 0;
    background: var(--white);
    border-bottom: 1px solid var(--gray-200);
    margin-bottom: var(--spacing-lg);
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
}

.hero-welcome {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-sm) 0;
}

.welcome-icon {
    flex-shrink: 0;
    width: 64px;
    height: 64px;
    background: var(--primary);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(0, 188, 212, 0.25);
    animation: float 3s ease-in-out infinite;
}

.welcome-icon i {
    font-size: 36px;
    color: var(--white);
    animation: wiggle 2s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-8px) rotate(5deg); }
}

@keyframes wiggle {
    0%, 100% { transform: rotate(0deg); }
    25% { transform: rotate(-5deg); }
    75% { transform: rotate(5deg); }
}

.welcome-text {
    flex: 1;
}

.hero-title {
    font-size: 24px;
    font-weight: 800;
    color: var(--text-dark);
    margin-bottom: var(--spacing-xs);
    line-height: 1.4;
}

.hero-stats {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-xs);
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: var(--gray-50);
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    flex: 0 0 auto;
    transition: all 0.3s ease;
    border: 1px solid var(--gray-200);
}

.stat-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    border-color: var(--primary);
    background: var(--white);
}

.stat-item i {
    font-size: 20px;
    color: var(--accent);
}

.stat-value {
    font-size: 18px;
    font-weight: 800;
    color: var(--primary);
}

.stat-label {
    font-size: 12px;
    color: var(--text-light);
    font-weight: 500;
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 700;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.btn-large {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 20px;
}

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

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

.btn-secondary {
    background: var(--accent);
    color: var(--text-dark);
}

.btn-secondary:hover {
    background: var(--accent-orange);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn i {
    margin-right: var(--spacing-xs);
}

/* ===================================
   Mini Games Section
   =================================== */
.mini-games {
    padding: var(--spacing-lg) 0;
    background: transparent;
}

.section-title {
    font-size: 32px;
    font-weight: 800;
    color: var(--text-dark);
    text-align: center;
    margin-bottom: var(--spacing-xl);
    position: relative;
    display: inline-block;
    width: 100%;
}

.section-title i {
    margin-right: var(--spacing-sm);
    color: var(--primary);
    animation: rotate-icon 3s ease-in-out infinite;
}

@keyframes rotate-icon {
    0%, 100% { transform: rotate(0deg); }
    25% { transform: rotate(-10deg); }
    75% { transform: rotate(10deg); }
}

.games-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 24px;
    max-width: 1200px;
    margin: 0 auto;
}

.game-card {
    background: var(--white);
    border-radius: 16px;
    padding: 28px 24px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    border: 2px solid var(--gray-200);
    position: relative;
    overflow: hidden;
}

.game-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.game-card:hover::before {
    transform: scaleX(1);
}

.game-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    border-color: var(--primary);
}

/* Game card colors - Clean & Modern */
.game-card:nth-child(1) {
    border-top-color: var(--primary);
}

.game-card:nth-child(1)::before {
    background: var(--primary);
}

.game-card:nth-child(2) {
    border-top-color: var(--secondary);
}

.game-card:nth-child(2)::before {
    background: var(--secondary);
}

.game-card:nth-child(3) {
    border-top-color: var(--accent-purple);
}

.game-card:nth-child(3)::before {
    background: var(--accent-purple);
}

.game-card:nth-child(4) {
    border-top-color: var(--accent-teal);
}

.game-card:nth-child(4)::before {
    background: var(--accent-teal);
}

.game-card:nth-child(5) {
    border-top-color: var(--accent-orange);
}

.game-card:nth-child(5)::before {
    background: var(--accent-orange);
}

.game-card:nth-child(6) {
    border-top-color: var(--accent-pink);
}

.game-card:nth-child(6)::before {
    background: var(--accent-pink);
}

.game-card:nth-child(7) {
    border-top-color: var(--secondary);
}

.game-card:nth-child(7)::before {
    background: var(--secondary);
}

.game-card:nth-child(8) {
    border-top-color: var(--accent-purple);
}

.game-card:nth-child(8)::before {
    background: var(--accent-purple);
}

.game-card:nth-child(9) {
    border-top-color: var(--accent-teal);
}

.game-card:nth-child(9)::before {
    background: var(--accent-teal);
}

.game-card:nth-child(10) {
    border-top-color: var(--primary);
}

.game-card:nth-child(10)::before {
    background: var(--primary);
}

.game-icon {
    font-size: 64px;
    margin-bottom: 16px;
    animation: bounce-gentle 2s ease-in-out infinite;
    color: var(--primary);
    transition: all 0.3s ease;
}

.game-card:hover .game-icon {
    transform: scale(1.1);
    color: var(--primary-dark);
}

@keyframes bounce-gentle {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-6px); }
}

.game-card h3 {
    font-size: 20px;
    font-weight: 800;
    color: var(--text-dark);
    margin-bottom: 8px;
    transition: all 0.3s ease;
    line-height: 1.3;
}

.game-card:hover h3 {
    color: var(--primary);
}

.game-card p {
    color: var(--text-light);
    font-size: 14px;
    font-weight: 500;
    line-height: 1.5;
}

/* ===================================
   Footer
   =================================== */
.footer {
    background: var(--dark-gray);
    color: var(--white);
    text-align: center;
    padding: var(--spacing-md) 0;
    margin-top: var(--spacing-xl);
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 768px) {
    .hero {
        padding: var(--spacing-xs) 0;
        border-radius: 0 0 20px 20px;
    }
    
    .hero-welcome {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-sm);
    }
    
    .welcome-icon {
        width: 60px;
        height: 60px;
    }
    
    .welcome-icon i {
        font-size: 30px;
    }
    
    .hero-title {
        font-size: 18px;
    }
    
    .hero-stats {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .stat-item {
        flex: 0 0 auto;
    }
    
    .header-content {
        flex-direction: row;
        gap: 15px;
        padding: 10px 0;
    }
    
    .logo {
        flex-shrink: 1;
        min-width: 0;
    }
    
    .logo h1 {
        font-size: 16px;
    }
    
    .logo i {
        font-size: 22px;
    }
    
    .nav {
        flex-wrap: nowrap;
        justify-content: flex-end;
        gap: 3px;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
        -ms-overflow-style: none;
    }
    
    .nav::-webkit-scrollbar {
        display: none;
    }
    
    .nav-link {
        padding: 6px 10px;
        font-size: 12px;
        gap: 5px;
    }
    
    .nav-link i {
        font-size: 13px;
        width: 14px;
    }
    
    .games-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .logo h1 {
        font-size: 14px;
    }
    
    .logo i {
        font-size: 20px;
    }
    
    .nav-link {
        padding: 6px 8px;
        font-size: 11px;
        gap: 4px;
    }
    
    .nav-link i {
        font-size: 12px;
        width: 13px;
    }
    
    /* Hide text on very small screens, show only icons */
    .nav-link span:not(.icon-text) {
        display: none;
    }
}

/* ===================================
   Utility Classes
   =================================== */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }