/**
 * Christmas 2025 Theme - Main Stylesheet
 * Professional Christmas Theme Design
 */

/* ========================================
   RESET & BASE STYLES
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Christmas Color Palette */
    --christmas-red: #c41e3a;
    --christmas-green: #165b33;
    --christmas-gold: #ffd700;
    --snow-white: #ffffff;
    --night-sky: #0a192f;
    --dark-green: #0d3d1f;
    --light-gold: #fff9e6;
    --silver: #c0c0c0;
    
    /* Gradients */
    --gradient-christmas: linear-gradient(135deg, var(--christmas-red), var(--christmas-green));
    --gradient-gold: linear-gradient(135deg, var(--christmas-gold), #ffed4e);
    --gradient-night: linear-gradient(180deg, #0a192f 0%, #1e3a5f 100%);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--night-sky);
    color: var(--snow-white);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
}

/* ========================================
   CHRISTMAS SCENE BACKGROUND
   ======================================== */
.christmas-scene {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

/* Sky Layer */
.sky-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 70%;
    background: linear-gradient(180deg, #0a0e27 0%, #1a1f3a 40%, #2d3e5f 70%, #4a5f7f 100%);
    overflow: hidden;
}

/* Stars */
.stars {
    position: absolute;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(2px 2px at 20% 30%, white, transparent),
        radial-gradient(2px 2px at 60% 70%, white, transparent),
        radial-gradient(1px 1px at 50% 50%, white, transparent),
        radial-gradient(1px 1px at 80% 10%, white, transparent),
        radial-gradient(2px 2px at 90% 60%, white, transparent),
        radial-gradient(1px 1px at 33% 85%, white, transparent),
        radial-gradient(2px 2px at 5% 20%, white, transparent),
        radial-gradient(1px 1px at 15% 45%, white, transparent),
        radial-gradient(2px 2px at 75% 25%, white, transparent),
        radial-gradient(1px 1px at 40% 15%, white, transparent);
    background-size: 300% 300%;
    animation: twinkle 4s ease-in-out infinite;
}

@keyframes twinkle {
    0%, 100% { opacity: 0.7; }
    50% { opacity: 1; }
}

/* Moon */
.moon {
    position: absolute;
    top: 8%;
    right: 12%;
    width: 120px;
    height: 120px;
    background: radial-gradient(circle at 35% 35%, #ffffff, #f5f5f5 50%, #e0e0e0);
    border-radius: 50%;
    box-shadow: 0 0 60px rgba(255, 255, 255, 0.8),
                0 0 100px rgba(255, 255, 255, 0.5),
                inset -10px -10px 20px rgba(0, 0, 0, 0.1);
    animation: moonGlow 3s ease-in-out infinite;
}

/* Moon craters */
.moon::before,
.moon::after {
    content: '';
    position: absolute;
    background: rgba(0, 0, 0, 0.05);
    border-radius: 50%;
}

.moon::before {
    width: 25px;
    height: 25px;
    top: 30%;
    left: 40%;
}

.moon::after {
    width: 18px;
    height: 18px;
    top: 50%;
    left: 55%;
}

@keyframes moonGlow {
    0%, 100% { 
        box-shadow: 0 0 60px rgba(255, 255, 255, 0.8),
                    0 0 100px rgba(255, 255, 255, 0.5); 
    }
    50% { 
        box-shadow: 0 0 80px rgba(255, 255, 255, 1),
                    0 0 120px rgba(255, 255, 255, 0.7); 
    }
}

/* Northern Lights Effect */
.northern-lights {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 60%;
    background: linear-gradient(180deg,
        transparent 0%,
        rgba(0, 255, 150, 0.1) 30%,
        rgba(0, 200, 255, 0.15) 50%,
        rgba(150, 0, 255, 0.1) 70%,
        transparent 100%);
    opacity: 0.6;
    animation: auroraWave 15s ease-in-out infinite;
}

@keyframes auroraWave {
    0%, 100% { 
        opacity: 0.4;
        transform: translateX(0) scaleY(1);
    }
    50% { 
        opacity: 0.7;
        transform: translateX(50px) scaleY(1.1);
    }
}

/* Santa Flying with Sleigh - Left to Right with Flip */
.santa-sleigh {
    position: absolute;
    top: 20%;
    Left: -200px; /* Start from Left */
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 3rem;
    animation: santaFly 45s cubic-bezier(0.4, 0, 0.2, 1) infinite;
    filter: drop-shadow(0 5px 15px rgba(255, 255, 255, 0.3));
    transform: scaleX(-1);  Flip entire sleigh to face left */
}

.santa-sleigh .reindeer {
    font-size: 2rem;
    letter-spacing: -5px;
    animation: reindeerRun 0.5s ease-in-out infinite;
    transform: scaleX(-1); /* Flip back reindeer */
}

.santa-sleigh .sleigh {
    font-size: 2.5rem;
    animation: sleighBounce 0.6s ease-in-out infinite;
    transform: scaleX(-1); /* Flip back sleigh */
}

.santa-sleigh .santa {
    animation: santaWave 1s ease-in-out infinite;
    transform: scaleX(-1); /* Flip back santa */
}

@keyframes santaFly {
    0% { 
        Left: -200px;
        top: 30%;
        transform: scaleX(-1) scale(0.6) translateZ(0);
        opacity: 0.7;
        filter: blur(1px) drop-shadow(0 5px 15px rgba(255, 255, 255, 0.2));
    }
    15% {
        Left: 15%;
        top: 22%;
        transform: scaleX(-1) scale(0.75) translateZ(0);
        opacity: 0.85;
        filter: blur(0.5px) drop-shadow(0 5px 15px rgba(255, 255, 255, 0.25));
    }
    30% {
        Left: 35%;
        top: 12%;
        transform: scaleX(-1) scale(0.95) translateZ(0);
        opacity: 0.95;
        filter: blur(0px) drop-shadow(0 5px 20px rgba(255, 255, 255, 0.35));
    }
    50% { 
        Left: 50%;
        top: 8%;
        transform: scaleX(-1) scale(1.1) translateZ(0);
        opacity: 1;
        filter: blur(0px) drop-shadow(0 8px 25px rgba(255, 255, 255, 0.4));
    }
    70% {
        Left: 65%;
        top: 12%;
        transform: scaleX(-1) scale(0.95) translateZ(0);
        opacity: 0.95;
        filter: blur(0px) drop-shadow(0 5px 20px rgba(255, 255, 255, 0.35));
    }
    85% {
        Left: 85%;
        top: 22%;
        transform: scaleX(-1) scale(0.75) translateZ(0);
        opacity: 0.85;
        filter: blur(0.5px) drop-shadow(0 5px 15px rgba(255, 255, 255, 0.25));
    }
    100% { 
        Left: calc(100% + 200px);
        top: 30%;
        transform: scaleX(-1) scale(0.6) translateZ(0);
        opacity: 0.7;
        filter: blur(1px) drop-shadow(0 5px 15px rgba(255, 255, 255, 0.2));
    }
}

@keyframes reindeerRun {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

@keyframes sleighBounce {
    0%, 100% { transform: rotate(-2deg) translateY(0); }
    50% { transform: rotate(-4deg) translateY(-3px); }
}

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

/* Ground Layer */
.ground-layer {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 40%;
    z-index: 1;
}

/* Hills with Snow */
.hill {
    position: absolute;
    bottom: 0;
    width: 100%;
    border-radius: 50% 50% 0 0;
}

.hill-back {
    height: 180px;
    background: linear-gradient(180deg, #d4e8ff 0%, #e8f4ff 100%);
    left: -10%;
    width: 120%;
    opacity: 0.5;
    transform: translateY(30px);
}

.hill-middle {
    height: 220px;
    background: linear-gradient(180deg, #e8f4ff 0%, #f0f8ff 100%);
    left: -5%;
    width: 110%;
    opacity: 0.7;
    transform: translateY(15px);
}

.hill-front {
    height: 260px;
    background: linear-gradient(180deg, #f0f8ff 0%, #ffffff 100%);
}

/* Ground Snow */
.ground-snow {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 120px;
    background: linear-gradient(180deg, #ffffff 0%, #f0f8ff 50%, #e8f4ff 100%);
    box-shadow: 0 -20px 40px rgba(255, 255, 255, 0.5);
}

/* Snowy Path */
.snowy-path {
    position: absolute;
    bottom: 50px;
    left: 10%;
    width: 80%;
    height: 60px;
    background: linear-gradient(90deg,
        transparent 0%,
        rgba(230, 240, 255, 0.6) 10%,
        rgba(240, 248, 255, 0.8) 50%,
        rgba(230, 240, 255, 0.6) 90%,
        transparent 100%);
    border-radius: 50%;
    transform: perspective(200px) rotateX(60deg);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

/* Houses */
.house {
    position: absolute;
    bottom: 120px;
    animation: houseGlow 3s ease-in-out infinite;
}

.house-1 {
    left: 15%;
    transform: scale(1.2);
}

.house-2 {
    right: 20%;
    transform: scale(0.9);
}

.house-body {
    width: 80px;
    height: 70px;
    background: linear-gradient(135deg, #8B4513 0%, #A0522D 100%);
    border-radius: 5px;
    position: relative;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

.house-roof {
    width: 0;
    height: 0;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    border-bottom: 40px solid #c41e3a;
    position: absolute;
    top: -40px;
    left: -10px;
    filter: drop-shadow(0 -3px 8px rgba(0, 0, 0, 0.2));
}

.house-roof::after {
    content: '';
    position: absolute;
    top: 0;
    left: -45px;
    width: 90px;
    height: 8px;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 50%;
    transform: translateY(40px);
}

.house-window {
    width: 18px;
    height: 20px;
    background: linear-gradient(135deg, #FFD700 0%, #FFA500 100%);
    border: 2px solid #654321;
    border-radius: 3px;
    position: absolute;
    top: 15px;
    box-shadow: 0 0 15px rgba(255, 215, 0, 0.8),
                inset 0 0 10px rgba(255, 255, 0, 0.5);
    animation: windowGlow 2s ease-in-out infinite;
}

.house-window:nth-child(3) {
    left: 12px;
}

.house-window:nth-child(4) {
    right: 12px;
}

@keyframes windowGlow {
    0%, 100% { 
        box-shadow: 0 0 15px rgba(255, 215, 0, 0.8);
        background: linear-gradient(135deg, #FFD700 0%, #FFA500 100%);
    }
    50% { 
        box-shadow: 0 0 25px rgba(255, 215, 0, 1),
                    0 0 35px rgba(255, 165, 0, 0.6);
        background: linear-gradient(135deg, #FFE55C 0%, #FFB84D 100%);
    }
}

.house-door {
    width: 22px;
    height: 35px;
    background: linear-gradient(180deg, #654321 0%, #4A3319 100%);
    border: 2px solid #3d2814;
    border-radius: 3px 3px 0 0;
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
}

.house-door::before {
    content: '🎄';
    position: absolute;
    top: 5px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 12px;
}

.chimney {
    width: 15px;
    height: 35px;
    background: linear-gradient(135deg, #8B4513 0%, #654321 100%);
    border: 2px solid #4A3319;
    border-radius: 2px 2px 0 0;
    position: absolute;
    top: -55px;
    right: 15px;
}

.smoke {
    position: absolute;
    width: 8px;
    height: 8px;
    background: rgba(200, 200, 200, 0.7);
    border-radius: 50%;
    animation: smokeRise 3s ease-in-out infinite;
}

.smoke:nth-child(1) {
    left: 3px;
    animation-delay: 0s;
}

.smoke:nth-child(2) {
    left: 3px;
    animation-delay: 1s;
}

.smoke:nth-child(3) {
    left: 3px;
    animation-delay: 2s;
}

@keyframes smokeRise {
    0% {
        transform: translateY(0) scale(1);
        opacity: 0.8;
    }
    100% {
        transform: translateY(-50px) scale(1.5);
        opacity: 0;
    }
}

@keyframes houseGlow {
    0%, 100% { filter: brightness(1); }
    50% { filter: brightness(1.1); }
}

/* Christmas Trees */
.tree {
    position: absolute;
    bottom: 120px;
    font-size: 4rem;
}

.tree-1 {
    left: 35%;
    transform: scale(1.3);
    animation: treeSwing 4s ease-in-out infinite;
}

.tree-2 {
    left: 55%;
    transform: scale(1);
    animation: treeSwing 5s ease-in-out infinite 0.5s;
}

.tree-3 {
    right: 10%;
    transform: scale(1.1);
    animation: treeSwing 4.5s ease-in-out infinite 1s;
}

.tree-top {
    filter: drop-shadow(0 5px 15px rgba(0, 100, 0, 0.5));
    animation: treeLightPulse 2s ease-in-out infinite;
}

.tree-lights {
    position: absolute;
    top: 10px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 50px;
}

.tree-lights::before,
.tree-lights::after {
    content: '✨';
    position: absolute;
    font-size: 0.8rem;
    animation: lightTwinkle 1.5s ease-in-out infinite;
}

.tree-lights::before {
    left: -10px;
    top: 5px;
}

.tree-lights::after {
    right: -10px;
    top: 15px;
    animation-delay: 0.75s;
}

@keyframes treeSwing {
    0%, 100% { transform: rotate(-1deg) scale(1); }
    50% { transform: rotate(1deg) scale(1.02); }
}

@keyframes treeLightPulse {
    0%, 100% { 
        filter: drop-shadow(0 5px 15px rgba(0, 100, 0, 0.5))
                brightness(1);
    }
    50% { 
        filter: drop-shadow(0 5px 25px rgba(255, 215, 0, 0.8))
                brightness(1.2);
    }
}

@keyframes lightTwinkle {
    0%, 100% { opacity: 0.5; transform: scale(0.8); }
    50% { opacity: 1; transform: scale(1.2); }
}

/* Snowmen */
.snowman {
    position: absolute;
    bottom: 120px;
    display: flex;
    flex-direction: column;
    align-items: center;
    animation: snowmanBob 3s ease-in-out infinite;
}

.snowman-1 {
    left: 25%;
    transform: scale(1.1);
}

.snowman-2 {
    right: 35%;
    transform: scale(0.9);
    animation-delay: 1s;
}

.snowman-base,
.snowman-body,
.snowman-head {
    background: radial-gradient(circle at 30% 30%, #ffffff, #f0f8ff);
    border-radius: 50%;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2),
                inset -5px -5px 10px rgba(0, 0, 0, 0.1);
}

.snowman-base {
    width: 50px;
    height: 50px;
}

.snowman-body {
    width: 40px;
    height: 40px;
    margin-top: -10px;
    position: relative;
}

.snowman-scarf {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 1.2rem;
}

.snowman-buttons {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #333;
    font-size: 0.6rem;
    font-weight: bold;
    letter-spacing: 2px;
}

.snowman-head {
    width: 30px;
    height: 30px;
    margin-top: -8px;
    position: relative;
}

.snowman-hat {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 1.2rem;
}

.snowman-eyes {
    position: absolute;
    top: 35%;
    left: 50%;
    transform: translateX(-50%);
    color: #333;
    font-size: 0.5rem;
    letter-spacing: 3px;
    font-weight: bold;
}

.snowman-nose {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 0.6rem;
}

.snowman-mouth {
    position: absolute;
    bottom: 20%;
    left: 50%;
    transform: translateX(-50%);
    color: #333;
    font-size: 0.8rem;
}

@keyframes snowmanBob {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

/* Old Northern Lights - Keep for compatibility */
.northern-lights {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        180deg,
        transparent 0%,
        rgba(0, 255, 127, 0.1) 50%,
        transparent 100%
    );
    opacity: 0.3;
    animation: northernLights 10s ease-in-out infinite;
}

@keyframes northernLights {
    0%, 100% { opacity: 0.2; transform: translateY(0); }
    50% { opacity: 0.4; transform: translateY(-20px); }
}

/* ========================================
   SNOWFLAKES
   ======================================== */
#snowflakes-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1000;
    overflow: hidden;
}

.snowflake {
    position: absolute;
    top: -10px;
    color: var(--snow-white);
    font-size: 1em;
    opacity: 0.8;
    animation: snowfall linear infinite;
    text-shadow: 0 0 5px rgba(255, 255, 255, 0.8);
    --drift: 0px;
}

@keyframes snowfall {
    0% {
        transform: translateY(0) translateX(0) rotate(0deg);
        opacity: 0.8;
    }
    50% {
        transform: translateY(50vh) translateX(var(--drift)) rotate(180deg);
    }
    100% {
        transform: translateY(100vh) translateX(0) rotate(360deg);
        opacity: 0;
    }
}

/* Sparkle Effects */
.sparkle-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 10;
}

.sparkle {
    position: absolute;
    animation: sparkleAnimation 2s ease-out forwards;
    filter: drop-shadow(0 0 5px rgba(255, 215, 0, 0.8));
}

@keyframes sparkleAnimation {
    0% {
        opacity: 0;
        transform: scale(0) rotate(0deg);
    }
    20% {
        opacity: 1;
        transform: scale(1.2) rotate(90deg);
    }
    80% {
        opacity: 0.8;
        transform: scale(1) rotate(270deg);
    }
    100% {
        opacity: 0;
        transform: scale(0.5) rotate(360deg);
    }
}

/* ========================================
   CHRISTMAS DECORATIONS
   ======================================== */
#christmas-decorations {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 5;
}

.decoration {
    position: absolute;
    font-size: 2em;
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(10deg); }
}

/* ========================================
   CONTAINER
   ======================================== */
.container {
    max-width: 1020px; /* Thu nhỏ để tránh Chatbox (400px) và Leaderboard (400px) */
    margin: 0 auto;
    padding: 10px 20px;
    position: relative;
    z-index: 10;
}

/* ========================================
   SECTION TITLES
   ======================================== */
.section-title {
    font-size: 1.44rem;
    text-align: center;
    margin: 20px 0;
    color: var(--snow-white);
    text-shadow: 
        0 0 10px rgba(255, 215, 0, 0.8),
        0 0 20px rgba(196, 30, 58, 0.6),
        2px 2px 4px rgba(0, 0, 0, 0.8);
    font-weight: bold;
    letter-spacing: 1px;
    animation: titleGlow 2s ease-in-out infinite;
}

@keyframes titleGlow {
    0%, 100% { 
        text-shadow: 
            0 0 10px rgba(255, 215, 0, 0.8),
            0 0 20px rgba(196, 30, 58, 0.6),
            2px 2px 4px rgba(0, 0, 0, 0.8);
    }
    50% { 
        text-shadow: 
            0 0 20px rgba(255, 215, 0, 1),
            0 0 30px rgba(196, 30, 58, 0.8),
            2px 2px 4px rgba(0, 0, 0, 0.8);
    }
}

/* ========================================
   COUNTDOWN SECTION
   ======================================== */
.countdown-section {
    background: transparent;
    border: none;
    border-radius: 0;
    padding: 20px 20px;
    margin: 20px auto; /* Center with auto */
    max-width: 100%; /* Không vượt quá container */
    box-shadow: none;
    position: relative;
    overflow: visible;
}

/* Christmas Flying Decorations */
.christmas-flying {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.decoration-container {
    position: absolute;
    animation: floatSlow 8s ease-in-out infinite;
}

.decoration-1 {
    top: 5%;
    left: 5%;
    animation-delay: 0s;
}

.decoration-2 {
    top: 5%;
    right: 10%;
    animation-delay: 1s;
}

.decoration-3 {
    bottom: 5%;
    left: 8%;
    animation-delay: 2s;
}

.decoration-4 {
    bottom: 5%;
    right: 5%;
    animation-delay: 3s;
}

.decoration-emoji {
    font-size: 2em;
    display: block;
    filter: drop-shadow(0 0 10px rgba(255, 215, 0, 0.6));
    animation: spin 4s linear infinite;
}

@keyframes floatSlow {
    0%, 100% { transform: translateY(0) translateX(0); }
    25% { transform: translateY(-15px) translateX(10px); }
    50% { transform: translateY(-30px) translateX(0); }
    75% { transform: translateY(-15px) translateX(-10px); }
}

@keyframes spin {
    0%, 100% { transform: rotate(0deg) scale(1); }
    50% { transform: rotate(180deg) scale(1.1); }
}

/* Countdown Timer */
.countdown {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin: 20px 0;
    position: relative;
    z-index: 1;
}

.countdown-item {
    background: transparent;
    border: none;
    border-radius: 0;
    padding: 15px 10px;
    min-width: 90px;
    text-align: center;
    box-shadow: none;
    transition: all 0.3s ease;
    position: relative;
    overflow: visible;
}

.countdown-item:hover {
    transform: translateY(-5px) scale(1.05);
}

.countdown-icon {
    font-size: 1.8em;
    margin-bottom: 5px;
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

.countdown-value {
    display: block;
    font-size: 2em;
    font-weight: bold;
    color: var(--christmas-gold);
    text-shadow: 
        0 0 10px rgba(255, 215, 0, 0.8),
        2px 2px 4px rgba(0, 0, 0, 0.8);
    font-family: 'Arial Black', sans-serif;
}

.countdown-label {
    display: block;
    font-size: 0.85em;
    color: var(--snow-white);
    margin-top: 5px;
    font-weight: 600;
    letter-spacing: 0.5px;
}

.title-with-decorations {
    position: relative;
    z-index: 1;
}

/* ========================================
   MUSIC SECTION
   ======================================== */
.music-section {
    background: linear-gradient(135deg, 
        rgba(22, 91, 51, 0.3),
        rgba(196, 30, 58, 0.3)
    );
    border: 3px solid var(--christmas-red);
    border-radius: 20px;
    padding: 20px;
    margin: 15px auto; /* Center with auto */
    max-width: 100%; /* Không vượt quá container */
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
}

.video-player {
    display: grid;
    grid-template-columns: 1fr;
    gap: 15px;
}

.video-container {
    position: relative;
    width: 100%;
    padding-bottom: 35%; /* Thu nhỏ để không bị che bởi Chatbox/Leaderboard */
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.5);
}

.video-container iframe,
.video-container #player {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

.playlist-section {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 15px;
    padding: 12px;
    max-height: 180px;
    overflow-y: auto;
}

.playlist {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.playlist-item {
    background: linear-gradient(135deg, 
        rgba(196, 30, 58, 0.4),
        rgba(22, 91, 51, 0.4)
    );
    border: 2px solid transparent;
    border-radius: 8px;
    padding: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.playlist-item:hover {
    border-color: var(--christmas-gold);
    transform: translateX(10px);
    box-shadow: 0 5px 20px rgba(196, 30, 58, 0.5);
}

.playlist-item.active {
    border-color: var(--christmas-gold);
    background: linear-gradient(135deg, 
        rgba(196, 30, 58, 0.7),
        rgba(22, 91, 51, 0.7)
    );
}

.playlist-item-thumbnail {
    width: 60px;
    height: 35px;
    border-radius: 5px;
    object-fit: cover;
}

.playlist-item-title {
    flex: 1;
    color: var(--snow-white);
    font-weight: 600;
    font-size: 0.9em;
}

/* Scrollbar Styling */
.playlist-section::-webkit-scrollbar {
    width: 10px;
}

.playlist-section::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 10px;
}

.playlist-section::-webkit-scrollbar-thumb {
    background: var(--christmas-red);
    border-radius: 10px;
}

.playlist-section::-webkit-scrollbar-thumb:hover {
    background: var(--christmas-gold);
}

/* ========================================
   QUOTE SECTION
   ======================================== */
.quote-section {
    background: linear-gradient(135deg, 
        rgba(22, 91, 51, 0.3),
        rgba(196, 30, 58, 0.3)
    );
    border: 3px solid var(--christmas-red);
    border-radius: 20px;
    padding: 20px;
    margin: 15px auto; /* Center with auto */
    max-width: 100%; /* Không vượt quá container */
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
}

.christmas-quote {
    background: linear-gradient(135deg, 
        rgba(196, 30, 58, 0.15),
        rgba(22, 91, 51, 0.15)
    );
    border: 2px solid var(--christmas-gold);
    border-radius: 15px;
    padding: 12px;
    box-shadow: 
        0 5px 20px rgba(0, 0, 0, 0.3),
        inset 0 0 20px rgba(255, 215, 0, 0.05);
    position: relative;
    overflow: hidden;
}

.quote-decoration {
    text-align: center;
    margin-bottom: 8px;
}

.joke-title {
    font-size: 1rem;
    color: var(--christmas-gold);
    font-weight: bold;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-shadow: 0 0 10px rgba(255, 215, 0, 0.6);
}

.quote-icon-left,
.quote-icon-right {
    font-size: 1em;
    color: var(--christmas-red);
}

.quote-snow-float {
    animation: floatSnow 3s ease-in-out infinite;
}

@keyframes floatSnow {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-10px) rotate(15deg); }
}

.quote-content {
    text-align: center;
    padding: 8px 10px;
    position: relative;
}

.quote-content .fa-quote-left {
    position: absolute;
    left: 10px;
    top: 5px;
    color: var(--christmas-gold);
    font-size: 1.2em;
    opacity: 0.6;
}

.quote-content .fa-quote-right {
    position: absolute;
    right: 10px;
    bottom: 5px;
    color: var(--christmas-gold);
    font-size: 1.2em;
    opacity: 0.6;
}

.quote-content p {
    font-size: 0.9rem;
    line-height: 1.4;
    color: var(--snow-white);
    margin: 8px 30px; /* Tăng margin để tránh quote icons */
    font-style: italic;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.6);
}

.quote-author-footer {
    text-align: right;
    font-size: 0.85rem;
    color: var(--christmas-gold);
    margin-top: 8px;
    font-weight: 600;
}

.quote-decoration-bottom {
    text-align: center;
    margin-top: 8px;
}

/* ========================================
   GALLERY SECTION
   ======================================== */
.gallery-section {
    display: none; /* Ẩn gallery section */
    margin: 30px 0;
    padding: 30px;
    background: linear-gradient(135deg, 
        rgba(22, 91, 51, 0.2),
        rgba(196, 30, 58, 0.2)
    );
    border-radius: 20px;
    border: 3px solid var(--christmas-green);
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.gallery-item {
    background: linear-gradient(135deg, 
        rgba(196, 30, 58, 0.3),
        rgba(22, 91, 51, 0.3)
    );
    border: 2px solid var(--christmas-gold);
    border-radius: 20px;
    padding: 30px;
    text-align: center;
    transition: all 0.4s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.gallery-item::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(
        circle,
        rgba(255, 215, 0, 0.2),
        transparent 70%
    );
    opacity: 0;
    transition: opacity 0.4s ease;
}

.gallery-item:hover::before {
    opacity: 1;
}

.gallery-item:hover {
    transform: translateY(-15px) scale(1.05);
    box-shadow: 
        0 20px 50px rgba(196, 30, 58, 0.6),
        inset 0 0 30px rgba(255, 215, 0, 0.2);
    border-color: var(--snow-white);
}

.gallery-placeholder {
    width: 100%;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 15px;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
}

.gallery-placeholder i {
    font-size: 5em;
    color: var(--christmas-gold);
    animation: iconPulse 2s ease-in-out infinite;
}

@keyframes iconPulse {
    0%, 100% { transform: scale(1); opacity: 0.8; }
    50% { transform: scale(1.2); opacity: 1; }
}

.gallery-item p {
    font-size: 1.3rem;
    color: var(--snow-white);
    font-weight: 600;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.6);
    position: relative;
    z-index: 1;
}

/* ========================================
   FOOTER
   ======================================== */
.footer {
    background: linear-gradient(135deg, 
        rgba(196, 30, 58, 0.4),
        rgba(22, 91, 51, 0.4)
    );
    border-top: 3px solid var(--christmas-gold);
    padding: 40px 20px;
    margin-top: 60px;
    text-align: center;
}

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

.copyright {
    font-size: 1.1rem;
    color: var(--snow-white);
    margin-bottom: 20px;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin: 20px 0;
    flex-wrap: wrap;
}

.social-links a {
    color: var(--christmas-gold);
    text-decoration: none;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.social-links a:hover {
    color: var(--snow-white);
    transform: translateY(-5px);
    text-shadow: 0 0 10px var(--christmas-gold);
}

.credit {
    font-size: 1rem;
    color: var(--light-gold);
    margin-top: 20px;
    font-style: italic;
}

/* ========================================
   PARTICLE CANVAS
   ======================================== */
#particle-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
}

/* ========================================
   RESPONSIVE DESIGN
   ======================================== */
@media (max-width: 768px) {
    .section-title {
        font-size: 1.5rem;
    }

    .countdown {
        gap: 8px;
    }

    .countdown-item {
        min-width: 75px;
        padding: 12px 8px;
    }

    .countdown-value {
        font-size: 1.8em;
    }

    .countdown-icon {
        font-size: 1.5em;
    }
    
    .video-container {
        padding-bottom: 50%; /* Tăng chiều cao trên mobile */
    }
    
    .playlist-section {
        max-height: 200px;
    }

    .gallery-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 15px;
    }

    .gallery-placeholder {
        height: 120px;
    }

    .gallery-placeholder i {
        font-size: 2.5em;
    }

    .quote-content p {
        font-size: 1.1rem;
    }

    .decoration-emoji {
        font-size: 1.5em;
    }

    .social-links {
        flex-direction: column;
        gap: 15px;
    }
    
    .music-section,
    .countdown-section {
        padding: 15px;
        margin: 15px 0;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 10px;
    }

    .section-title {
        font-size: 1.3rem;
        margin: 15px 0;
    }

    .countdown-item {
        min-width: 65px;
        padding: 10px 5px;
    }

    .countdown-value {
        font-size: 1.5em;
    }

    .countdown-label {
        font-size: 0.75em;
    }
    
    .countdown-icon {
        font-size: 1.3em;
    }

    .moon {
        width: 80px;
        height: 80px;
    }
    
    .video-container {
        padding-bottom: 56.25%; /* 16:9 trên mobile */
    }
}

/* ========================================
   ANIMATIONS
   ======================================== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.6s ease-out;
}

/* Loading Animation */
@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading {
    display: inline-block;
    width: 50px;
    height: 50px;
    border: 5px solid var(--christmas-gold);
    border-top-color: var(--christmas-red);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* Video Title Header - Dynamic Title Display */
.video-title-header {
    margin-bottom: 15px;
    text-align: center;
    font-size: 1.056rem;
    color: var(--christmas-gold);
    text-shadow: 0 2px 8px rgba(255, 215, 0, 0.5);
    transition: all 0.3s ease;
}

.video-title-header:hover {
    color: var(--snow-white);
    text-shadow: 0 3px 12px rgba(255, 255, 255, 0.6);
    transform: scale(1.02);
}