html {
    scroll-behavior: smooth;
}
body {
    font-family: 'Noto Sans KR', sans-serif;
    background-color: #ffffff;
    color: #334155;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.serif-font { font-family: 'Nanum Myeongjo', serif; }
.script-font { font-family: 'Great Vibes', cursive; }
.handwriting-font { font-family: 'Nanum Pen Script', cursive; }

.sky-theme-bg {
    background: linear-gradient(to bottom, #3A7BD5 0%, #3A7BD5 60%, #ffffff 100%);
}

.hero-section {
    position: relative;
    height: 100vh;
    height: 100dvh;
    min-height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: #3A7BD5;
}

.star-trail {
    position: absolute;
    top: 15%;
    left: 0;
    width: 100%;
    opacity: 0.6;
    pointer-events: none;
}
.cloud-bottom {
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: auto;
    z-index: 2;
}

.main-title {
    color: white;
    text-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.card-shadow {
    box-shadow: 0 10px 25px -5px rgba(58, 123, 213, 0.1);
    transition: all 0.3s ease;
}
.card-shadow:hover {
     box-shadow: 0 20px 40px -5px rgba(58, 123, 213, 0.2);
}

.btn-outline-white {
    border: 1px solid rgba(255, 255, 255, 0.5);
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(5px);
    color: white;
    transition: all 0.3s ease;
}
.btn-outline-white:hover {
    background: white;
    color: #3A7BD5;
}

.instructor-card:hover .instructor-info {
    transform: translateY(-5px);
}
.instructor-info {
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.neon-text {
    color: #fff;
    text-shadow:
        0 0 2px #fff,
        0 0 5px #fff,
        0 0 15px #B3E5FC,
        0 0 30px #B3E5FC;
}

.re-gradient {
    background: linear-gradient(to bottom, #E1F5FE 0%, #4FC3F7 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: none;
    filter: drop-shadow(0 0 2px rgba(255, 255, 255, 0.9))
            drop-shadow(0 0 8px #B3E5FC);
}

@keyframes floatCloud {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100vw); }
}

.cloud-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    z-index: 1;
    pointer-events: none;
}

.cloud {
    position: absolute;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 100px;
    animation: floatCloud linear infinite;
}

.cloud::after, .cloud::before {
    content: '';
    position: absolute;
    background: inherit;
    border-radius: 50%;
}

.cloud::after { width: 50px; height: 50px; top: -25px; left: 25px; }
.cloud::before { width: 70px; height: 70px; top: -35px; right: 25px; }

.c1 { width: 120px; height: 40px; top: 15%; animation-duration: 35s; opacity: 0.3; }
.c2 { width: 180px; height: 60px; top: 25%; left: -20%; animation-duration: 45s; animation-delay: 5s; opacity: 0.15; transform: scale(1.5); }
.c3 { width: 100px; height: 35px; top: 40%; animation-duration: 28s; animation-delay: 2s; opacity: 0.2; }
.c4 { width: 150px; height: 50px; top: 10%; animation-duration: 40s; animation-delay: 15s; opacity: 0.25; }
.c5 { width: 200px; height: 70px; top: 60%; animation-duration: 50s; animation-delay: 8s; opacity: 0.1; }

.cursor-blink {
    animation: blink 1s step-end infinite;
    display: inline-block;
    vertical-align: text-bottom;
    font-weight: 100;
}
@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

@keyframes twinkle {
    0%, 100% {
        opacity: 1;
        text-shadow:
            0 0 4px #fff,
            0 0 12px #fff,
            0 0 25px #B3E5FC,
            0 0 45px #B3E5FC;
    }
    50% {
        opacity: 0.7;
        text-shadow:
            0 0 2px #fff,
            0 0 5px #fff,
            0 0 15px #B3E5FC,
            0 0 30px #B3E5FC;
    }
}
.animate-twinkle {
    animation: twinkle 2.5s ease-in-out infinite;
}

.paper-plane {
    position: absolute;
    bottom: 15%;
    left: 10%;
    color: rgba(255, 255, 255, 0.9);
    z-index: 5;
    filter: drop-shadow(2px 4px 6px rgba(0,0,0,0.1));
    animation: fly 15s linear infinite;
    pointer-events: none;
}

.paper-plane svg {
    width: 3rem;
    height: 3rem;
    fill: currentColor;
}

@keyframes fly {
    0% {
        transform: translate(0, 0) rotate(0deg) scale(0.8);
        opacity: 0;
    }
    5% {
        opacity: 1;
    }
    80% {
        opacity: 0.8;
    }
    100% {
        transform: translate(80vw, -60vh) rotate(20deg) scale(0.5);
        opacity: 0;
    }
}

.neon-emphasis {
    color: #10b981;
    text-shadow:
        0 0 2px #fff,
        0 0 5px #34d399,
        0 0 10px rgba(16, 185, 129, 0.5);
}

.hide-scrollbar::-webkit-scrollbar {
    display: none;
}
.hide-scrollbar {
    -ms-overflow-style: none;
    scrollbar-width: none;
}

@keyframes wave-text {
    0% { background-position: 0% 50%; }
    100% { background-position: 200% 50%; }
}
.wave-text-anim {
    background: linear-gradient(to right, #2563eb, #22d3ee, #2563eb);
    background-size: 200% auto;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    animation: wave-text 3s linear infinite;
}

@keyframes wave-gold {
    0% { background-position: 0% 50%; }
    100% { background-position: 200% 50%; }
}
.gold-wave-text {
    background: linear-gradient(to right, #C5A059, #F3E5AB, #E6C288, #D4AF37, #C5A059);
    background-size: 200% auto;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    animation: wave-gold 14s linear infinite;
    text-shadow: none;
    display: inline-block;
}

.mobile-menu {
    transition: transform 0.3s ease-in-out;
    transform: translateX(100%);
}
.mobile-menu.open {
    transform: translateX(0);
}

/* Nav scrolled state */
nav.scrolled {
    background-color: rgba(255, 255, 255, 0.97) !important;
    border-bottom-color: rgba(226, 232, 240, 0.8) !important;
    box-shadow: 0 2px 16px rgba(0, 0, 0, 0.06);
}
nav.scrolled > div > div:first-child {
    color: #1e293b !important;
}
nav.scrolled > div > div.hidden a {
    color: #475569 !important;
}
nav.scrolled > div > div.hidden a:hover {
    color: #3b82f6 !important;
}
nav.scrolled #mobile-menu-btn {
    color: #1e293b !important;
}