/* ==========================================
   WELCOME ITK25 - SEQUENTIAL NORMAL TYPOGRAPHY STYLES
   ========================================== */

:root {
    --font-heading: 'Orbitron', sans-serif;
    --font-sans: 'Outfit', 'Montserrat', sans-serif;
    --font-script: 'Dancing Script', cursive;
    --color-cyan: #00f2fe;
    --color-pink: #ff2a8d;
    --color-gold: #ffaa00;
    --color-green: #00ff88;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    user-select: none;
    -webkit-user-select: none;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: #04020a;
    color: #ffffff;
    font-family: var(--font-sans);
    position: fixed;
}

/* Shifting Aurora Background Layer */
.aurora-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: linear-gradient(-45deg, #090314, #18052e, #041b2d, #260421, #031822);
    background-size: 400% 400%;
    animation: auroraShift 16s ease infinite;
    z-index: 0;
}

/* Master Canvas */
#mainCanvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    display: block;
    z-index: 1;
}

/* ==========================================
   SEQUENTIAL STAGE OVERLAY
   ========================================== */
.stage-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 10;
    pointer-events: none;
}

.seq-stage {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.7);
    opacity: 0;
    visibility: hidden;
    width: 90%;
    max-width: 850px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1.2rem;
    transition: opacity 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275),
                transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.seq-stage.active {
    opacity: 1;
    visibility: visible;
    transform: translate(-50%, -50%) scale(1);
    pointer-events: auto;
}

.seq-stage.fade-out {
    opacity: 0;
    visibility: hidden;
    transform: translate(-50%, -50%) scale(1.2);
}

/* Countdown Numbers (3, 2, 1) */
.num-text {
    font-family: var(--font-heading);
    font-size: clamp(6rem, 25vw, 14rem);
    font-weight: 900;
    background: linear-gradient(135deg, #ffffff 0%, #00f2fe 50%, #ff2a8d 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 35px rgba(0, 242, 254, 0.85));
    line-height: 1;
}

/* WELCOME ITK25 Stage */
.welcome-text {
    font-family: var(--font-script);
    font-size: clamp(2.2rem, 7.5vw, 4.8rem);
    font-weight: 700;
    letter-spacing: 2px;
    background: linear-gradient(135deg, #ffffff 0%, #00f2fe 40%, #ff2a8d 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 30px rgba(0, 242, 254, 0.8));
    line-height: 1.15;
}

/* LIÊN KHỐI CHUYÊN TIN Stage */
.lienkhoi-title {
    font-family: var(--font-script);
    font-size: clamp(1.4rem, 5.5vw, 3rem);
    font-weight: 700;
    letter-spacing: 1.5px;
    color: #ffffff;
    text-transform: uppercase;
    text-shadow: 0 0 25px rgba(255, 255, 255, 0.8),
                 0 0 45px rgba(0, 242, 254, 0.7);
    line-height: 1.2;
}

.year-subtitle {
    font-family: var(--font-heading);
    font-size: clamp(1.2rem, 4.2vw, 2.2rem);
    font-weight: 800;
    letter-spacing: 3px;
    color: var(--color-gold);
    text-shadow: 0 0 25px rgba(255, 170, 0, 0.7);
    margin-top: 0.5rem;
}

/* Keyframes */
@keyframes auroraShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}