:root {
    --primary: #ff4757;
    --secondary: #ffa502;
    --accent: #1e90ff;
    --bg-light: #f1f2f6;
    --text-dark: #2f3542;
    --text-muted: #57606f;
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.5);
    --glass-hover: rgba(255, 255, 255, 0.95);
    --glass-shadow: 0 10px 40px -10px rgba(0, 0, 0, 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif; /* Chuyển sang Inter hiển thị tiếng Việt in hoa tốt hơn */
}

body {
    background-color: var(--bg-light);
    color: var(--text-dark);
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
    -webkit-font-smoothing: antialiased;
    padding: 3rem 1rem 0;
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Animated Background Shapes - Softer Theme */
.background {
    position: fixed;
    width: 100vw;
    height: 100vh;
    top: 0;
    left: 0;
    z-index: -1;
    overflow: hidden;
    filter: blur(100px);
}

.shape {
    position: absolute;
    border-radius: 50%;
    animation: float 30s infinite alternate cubic-bezier(0.45, 0.05, 0.55, 0.95);
    opacity: 0.4;
}

/* Sử dụng các màu dịu mắt hơn cho ban đêm (Soft Pastels/Muted Tones) */
.shape-1 {
    width: 60vw;
    height: 60vw;
    background: radial-gradient(circle, #e0c3fc 0%, transparent 60%);
    top: -20%;
    left: -10%;
}

.shape-2 {
    width: 50vw;
    height: 50vw;
    background: radial-gradient(circle, #8ec5fc 0%, transparent 60%);
    bottom: -10%;
    right: -10%;
    animation-delay: -5s;
    animation-duration: 35s;
}

.shape-3 {
    width: 45vw;
    height: 45vw;
    background: radial-gradient(circle, #a1c4fd 0%, transparent 60%);
    top: 40%;
    left: 30%;
    animation-delay: -10s;
    animation-duration: 25s;
}

.shape-4 {
    width: 70vw;
    height: 30vw;
    background: radial-gradient(circle, #c2e9fb 0%, transparent 70%);
    bottom: -20%;
    left: 10%;
    animation-delay: -15s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1) rotate(0deg); }
    100% { transform: translate(60px, 80px) scale(1.1) rotate(15deg); }
}

/* Header */
.main-header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeSlideUp 1s ease-out forwards;
}

.main-title {
    font-size: 3.5rem;
    font-weight: 800;
    color: var(--primary); /* Đã thay thế hiệu ứng cắt chữ gradient gây lỗi font tiếng Việt */
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
    line-height: 1.2;
    text-shadow: 0 4px 15px rgba(255, 71, 87, 0.2);
}

.main-subtitle {
    font-size: 1.1rem;
    font-weight: 600;
    letter-spacing: 4px;
    text-transform: uppercase;
    color: var(--text-muted);
}

@keyframes fadeSlideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Main Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
}

/* SECTION DIVIDER & TITLE */
.section-divider {
    border: 0;
    height: 1px;
    background: linear-gradient(to right, transparent, rgba(0,0,0,0.1), transparent);
    margin: 4rem 0 3rem;
}

.section-title {
    text-align: center;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 2rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* FEATURED SECTION (Top, Center, Largest) */
.featured-section {
    display: flex;
    justify-content: center;
    width: 100%;
    margin-bottom: 2rem;
}

.featured-card {
    width: 100%;
    max-width: 800px;
    padding: 4rem 3rem !important;
    text-align: center;
    border-radius: 32px !important;
    background: rgba(255,255,255,0.9) !important;
    box-shadow: 0 20px 50px rgba(0,0,0,0.1) !important;
}

.featured-card .card-title {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(to right, #ff4757, #ffa502);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1rem;
}

.featured-card .card-date {
    font-size: 1.2rem;
    font-weight: 600;
    padding: 0.5rem 1.5rem;
    background: rgba(255, 71, 87, 0.1);
    color: var(--primary);
    border-radius: 50px;
}

/* Custom large timer for featured section */
.featured-card .mini-countdown {
    gap: 2rem;
    margin-top: 3rem;
}

.featured-card .mini-time-box {
    background: linear-gradient(145deg, #ffffff, #f0f0f0);
    padding: 1.5rem 1rem;
    border-radius: 20px;
    min-width: 100px;
    border: 1px solid rgba(0,0,0,0.05);
    box-shadow: 5px 5px 15px rgba(0,0,0,0.05), -5px -5px 15px rgba(255,255,255,1);
}

.featured-card .mini-time {
    font-size: 3.5rem;
    color: var(--text-dark);
    text-shadow: none;
}

.featured-card .mini-label {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 600;
    margin-top: 0.5rem;
}

/* Grid for the Rest */
.holidays-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    padding: 1rem 0;
}

/* Glassmorphism Standard Card */
.holiday-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 24px;
    padding: 2.5rem 2rem;
    box-shadow: var(--glass-shadow);
    text-align: center;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    animation: fadeIn 0.8s ease-out forwards;
    opacity: 0;
    transform: translateY(20px);
}

.holiday-card:hover {
    transform: translateY(-8px) scale(1.02);
    background: var(--glass-hover);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.12);
}

@keyframes fadeIn {
    to { opacity: 1; transform: translateY(0); }
}

/* Card Content Standard */
.card-header {
    margin-bottom: 1.5rem;
}

.card-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.card-date {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--accent);
    background: rgba(30, 144, 255, 0.1);
    padding: 0.3rem 1rem;
    border-radius: 20px;
    display: inline-block;
}

/* Mini Countdown */
.mini-countdown {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 2rem;
}

.mini-time-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: rgba(255,255,255,0.6);
    padding: 0.8rem 0.5rem;
    border-radius: 12px;
    min-width: 60px;
    border: 1px solid rgba(255,255,255,0.8);
    box-shadow: 0 4px 10px rgba(0,0,0,0.03);
}

.mini-time {
    font-size: 1.8rem;
    font-weight: 700;
    line-height: 1;
    font-variant-numeric: tabular-nums;
    color: var(--text-dark);
}

.mini-label {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
    margin-top: 0.4rem;
}

.celebrate-msg {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    margin-top: 2rem;
    animation: pulseMsg 2s infinite;
}

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

/* SEO Content Section */
.seo-content {
    margin-top: 5rem;
    padding: 3rem;
    background: var(--glass-bg);
    border-radius: 24px;
    box-shadow: var(--glass-shadow);
    color: var(--text-dark);
    line-height: 1.8;
    backdrop-filter: blur(20px);
}

.seo-content h2 {
    font-size: 2.2rem;
    margin-bottom: 1.5rem;
    color: var(--primary);
    text-align: center;
}

.seo-content > p {
    font-size: 1.1rem;
    margin-bottom: 3rem;
    text-align: center;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.article-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.article-block {
    background: rgba(255,255,255,0.5);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid rgba(255,255,255,0.8);
}

.article-block h3 {
    font-size: 1.3rem;
    color: var(--accent);
    margin-bottom: 1rem;
}

.article-block p {
    font-size: 1rem;
    color: var(--text-muted);
}

/* Footer AdSense Compliance */
.site-footer {
    width: 100%;
    margin-top: 5rem;
    background: #ffffff;
    padding: 2rem 0;
    text-align: center;
    border-top: 1px solid rgba(0,0,0,0.05);
}

.footer-bottom p {
    color: var(--text-muted);
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.3s;
}

.footer-links a:hover {
    color: var(--primary);
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    .main-title {
        font-size: 2.2rem;
    }
    
    .featured-card {
        padding: 2.5rem 1.5rem !important;
    }
    
    .featured-card .card-title {
        font-size: 1.8rem;
    }
    
    .featured-card .mini-countdown {
        gap: 0.8rem;
    }
    
    .featured-card .mini-time-box {
        min-width: 70px;
        padding: 1rem 0.5rem;
    }
    
    .featured-card .mini-time {
        font-size: 2rem;
    }

    .holidays-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
        gap: 1.5rem;
    }
    
    .seo-content {
        padding: 2rem 1.5rem;
    }
}