/* 레이아웃 & 배경 */
.hero-gradient,
.challenge-gradient {
    background: radial-gradient(circle at 50% -20%, var(--bg-orange-tint) 0%, var(--bg-light) 60%);
}

/* 내비게이션 */
#main-nav {
    /* 기본 상태: 전체 너비 */
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

#main-nav.nav-scrolled {
    /* 스크롤 상태: 너비 축소 및 둥근 모서리 */
    top: 15px;
    width: 90%;
    max-width: 1200px;
    border-radius: 100px;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

/* 컴포넌트 스타일 */
.feature-card {
    background: white;
    border: 1px solid var(--border-light);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.02);
    transition: var(--transition-standard);
    will-change: transform;
}

.feature-card:hover {
    border-color: var(--brand-orange);
    transform: translateY(-5px);
    box-shadow: 0 10px 15px -3px rgba(255, 154, 0, 0.1);
}

.text-gradient {
    background: linear-gradient(to right, var(--text-dark), var(--brand-orange));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}


/* 로딩 스피너 */
.btn-spinner {
    position: absolute;
    top: 50%;
    right: 12px;
    margin-top: -7px;
    width: 14px;
    height: 14px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: #fff;
    border-radius: 50%;
    display: none;
}

.btn-loading .btn-spinner {
    display: block;
    animation: spin 0.8s linear infinite;
}

/* 키프레임 통합 */
@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-15px);
    }
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }

    to {
        transform: rotate(360deg);
    }
}

/* 반응형 조정 */
/* 모바일 메뉴 오버레이 애니메이션 */
#mobile-menu {
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

#mobile-menu.hidden-menu {
    transform: translateY(-100%);
}

#mobile-menu.active-menu {
    transform: translateY(0);
}

/* 햄버거 아이콘 애니메이션 */
.menu-icon span {
    display: block;
    width: 24px;
    height: 2px;
    background: #1e293b;
    margin: 5px 0;
    transition: 0.3s;
}

.menu-icon.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.menu-icon.active span:nth-child(2) {
    opacity: 0;
}

.menu-icon.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}


/* 햄버거 메뉴 애니메이션 */
.menu-active .bar-1 {
    transform: translateY(8px) rotate(45deg);
}

.menu-active .bar-2 {
    opacity: 0;
}

.menu-active .bar-3 {
    transform: translateY(-8px) rotate(-45deg);
}