:root {
    --bg-dark: #f1f5f9; /* 은은한 밝은 회색 */
    --bg-card: rgba(255, 255, 255, 0.82); /* 우아한 흰색 반투명 유리 */
    --border-glass: rgba(15, 23, 42, 0.08); /* 엷은 어두운색 유리 테두리 */
    --neon-cyan: #0891b2; /* 짙은 시안 */
    --neon-blue: #2563eb; /* 선명한 블루 */
    --neon-purple: #7c3aed; /* 짙은 퍼플 */
    --neon-red: #dc2626; /* 선명한 레드 */
    --text-primary: #0f172a; /* 짙은 slate-900 */
    --text-secondary: #475569; /* slate-600 */
}

body {
    background: radial-gradient(circle at 50% 50%, #f8fafc 0%, var(--bg-dark) 100%);
    color: var(--text-primary);
    font-family: 'Outfit', 'Inter', sans-serif;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    position: relative;
}

/* 배경 장식 애니메이션 광원 */
.glow-sphere {
    position: absolute;
    border-radius: 50%;
    filter: blur(140px);
    z-index: 0;
    opacity: 0.35;
    animation: floatGlow 15s infinite alternate ease-in-out;
}

.glow-sphere-1 {
    width: 450px;
    height: 450px;
    background: linear-gradient(135deg, #a5f3fc, #bfdbfe);
    top: -100px;
    left: -100px;
}

.glow-sphere-2 {
    width: 550px;
    height: 550px;
    background: linear-gradient(135deg, #ddd6fe, #bfdbfe);
    bottom: -150px;
    right: -150px;
    animation-delay: -5s;
}

@keyframes floatGlow {
    0% {
        transform: translate(0, 0) scale(1);
    }
    100% {
        transform: translate(60px, 40px) scale(1.15);
    }
}

/* 메인 카드 */
.gate-card {
    background: var(--bg-card);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border: 1px solid var(--border-glass);
    border-radius: 28px;
    box-shadow: 0 20px 50px rgba(15, 23, 42, 0.08);
    width: 100%;
    max-width: 450px;
    padding: 3.5rem 2.5rem;
    z-index: 10;
    position: relative;
    animation: fadeInUp 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 로고 스타일 */
.brand-logo {
    font-family: 'Outfit';
    font-weight: 800;
    font-size: 2.1rem;
    letter-spacing: 1.5px;
    text-align: center;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.neon-text {
    background: linear-gradient(135deg, var(--neon-cyan), var(--neon-blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.brand-subtitle {
    font-size: 0.9rem;
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: 2.5rem;
    letter-spacing: 0.5px;
    font-weight: 500;
}

/* 폼 입력 요소 */
.input-group-custom {
    position: relative;
    margin-bottom: 1.5rem;
}

.input-custom {
    width: 100%;
    background: rgba(255, 255, 255, 0.85) !important;
    border: 1px solid rgba(15, 23, 42, 0.12) !important;
    border-radius: 14px !important;
    padding: 1rem 1.25rem 1rem 3rem !important;
    color: var(--text-primary) !important;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s ease;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.05);
}

.input-custom:focus {
    outline: none;
    border-color: var(--neon-cyan) !important;
    box-shadow: 0 0 0 4px rgba(8, 145, 178, 0.15), inset 0 1px 3px rgba(0, 0, 0, 0.05) !important;
}

.input-icon-left {
    position: absolute;
    left: 1.25rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    font-size: 1.1rem;
    transition: color 0.3s ease;
    z-index: 10;
}

.input-custom:focus + .input-icon-left {
    color: var(--neon-cyan);
}

.input-icon-right {
    position: absolute;
    right: 1.25rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 1.1rem;
    z-index: 10;
    transition: color 0.2s;
}

.input-icon-right:hover {
    color: var(--text-primary);
}

/* 제출 버튼 */
.btn-submit {
    background: linear-gradient(135deg, var(--neon-cyan) 0%, var(--neon-blue) 100%);
    border: none;
    border-radius: 14px;
    color: white;
    font-weight: 600;
    padding: 1rem;
    width: 100%;
    font-size: 1.05rem;
    letter-spacing: 0.5px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 15px rgba(8, 145, 178, 0.2);
}

.btn-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(8, 145, 178, 0.35);
    background: linear-gradient(135deg, #0e7490 0%, #1d4ed8 100%);
}

.btn-submit:active {
    transform: translateY(0);
}

/* 에러 메시지 */
.error-alert {
    background: rgba(220, 38, 38, 0.05);
    border: 1px solid rgba(220, 38, 38, 0.15);
    border-radius: 12px;
    color: var(--neon-red);
    padding: 0.85rem 1rem;
    font-size: 0.85rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
    animation: shake 0.5s ease-in-out;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    10%, 30%, 50%, 70%, 90% { transform: translateX(-6px); }
    20%, 40%, 60%, 80% { transform: translateX(6px); }
}

.footer-text {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-align: center;
    margin-top: 2rem;
    font-weight: 400;
}

/* 모바일 화면 반응형 최적화 */
@media (max-width: 576px) {
    .gate-card {
        width: calc(100% - 32px); /* 좌우 16px씩 마진 확보 */
        margin: 16px;
        padding: 2.5rem 1.5rem; /* 모바일용 패딩 축소 */
        border-radius: 24px; /* 살짝 둥글게 조절 */
    }
    .brand-logo {
        font-size: 1.8rem; /* 폰트 크기 살짝 축소 */
    }
    .brand-subtitle {
        margin-bottom: 2rem;
    }
    .input-custom {
        padding: 0.9rem 1.25rem 0.9rem 2.75rem !important; /* 폼 요소 높이 조절 */
    }
    .btn-submit {
        padding: 0.9rem;
    }
}