/* Design Tokens & Reset */
:root {
    --bg-color: #0b0f19;
    --card-bg: rgba(17, 24, 39, 0.7);
    --card-border: rgba(255, 255, 255, 0.08);
    --text-primary: #f3f4f6;
    --text-secondary: #9ca3af;
    --accent-primary: #3b82f6;      /* Bright Blue */
    --accent-secondary: #6366f1;    /* Indigo */
    --accent-gradient: linear-gradient(135deg, var(--accent-secondary) 0%, var(--accent-primary) 100%);
    --font-outfit: 'Outfit', sans-serif;
    --font-rubik: 'Rubik', 'Noto Sans KR', sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-rubik);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    position: relative;
}

/* Background Glow Effects */
.glow-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.glow-sphere {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.15;
    mix-blend-mode: screen;
}

.glow-sphere-1 {
    top: -10%;
    right: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, var(--accent-secondary) 0%, transparent 70%);
    animation: float 20s infinite alternate;
}

.glow-sphere-2 {
    bottom: -15%;
    left: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--accent-primary) 0%, transparent 70%);
    animation: float 25s infinite alternate-reverse;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(50px, 30px) scale(1.1); }
}

/* Main Container */
.container {
    width: 100%;
    max-width: 480px;
    padding: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 10;
}

/* Premium Card */
.card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 28px;
    width: 100%;
    padding: 40px 32px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3), inset 0 1px 0 rgba(255, 255, 255, 0.05);
    text-align: center;
    animation: slideUp 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

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

/* Branding Section */
.brand-section {
    margin-bottom: 36px;
}

.logo-wrapper {
    display: inline-block;
    width: 110px;
    height: 110px;
    border-radius: 24px;
    padding: 5px;
    background: linear-gradient(135deg, rgba(255,255,255,0.1) 0%, rgba(255,255,255,0.02) 100%);
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 12px 24px rgba(0,0,0,0.2);
    margin-bottom: 20px;
    overflow: hidden;
    transition: transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.logo-wrapper:hover {
    transform: scale(1.05) rotate(3deg);
}

.app-logo {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 20px;
}

.app-title {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 8px;
    background: linear-gradient(to right, #ffffff, #e2e8f0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.app-title-en {
    font-family: var(--font-outfit);
    font-weight: 300;
    font-size: 1.6rem;
    color: var(--text-secondary);
    margin-left: 4px;
    -webkit-text-fill-color: initial; /* Reset gradient clip */
}

.app-tagline {
    font-size: 0.95rem;
    color: var(--text-secondary);
    font-weight: 400;
    letter-spacing: 0.2px;
}

/* Download Section */
.download-section {
    margin-bottom: 40px;
}

.download-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent-gradient);
    color: #ffffff;
    text-decoration: none;
    padding: 16px 28px;
    border-radius: 20px;
    font-weight: 600;
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.3), 0 12px 40px rgba(59, 130, 246, 0.2);
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.download-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        90deg,
        transparent,
        rgba(255, 255, 255, 0.2),
        transparent
    );
    transition: 0.5s;
}

.download-btn:hover::before {
    left: 100%;
    transition: 0.7s;
}

.download-btn:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(99, 102, 241, 0.5), 0 20px 50px rgba(59, 130, 246, 0.3);
}

.download-btn:active {
    transform: translateY(-1px);
}

.btn-icon {
    width: 28px;
    height: 28px;
    margin-right: 14px;
    flex-shrink: 0;
}

.btn-icon svg {
    width: 100%;
    height: 100%;
}

.btn-text {
    display: flex;
    flex-direction: column;
    text-align: left;
}

.btn-primary-text {
    font-size: 1.15rem;
    letter-spacing: 0.5px;
}

.btn-secondary-text {
    font-size: 0.75rem;
    opacity: 0.85;
    font-weight: 400;
    margin-top: 2px;
}

.download-info {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 14px;
}

/* Instructions Section */
.instructions-section {
    border-top: 1px solid rgba(255, 255, 255, 0.06);
    padding-top: 32px;
    text-align: left;
}

.instructions-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-primary);
    text-align: center;
}

.steps {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.step-card {
    display: flex;
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid rgba(255, 255, 255, 0.03);
    border-radius: 16px;
    padding: 16px;
    transition: background 0.3s ease;
}

.step-card:hover {
    background: rgba(255, 255, 255, 0.04);
}

.step-num {
    background: rgba(59, 130, 246, 0.15);
    color: var(--accent-primary);
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.9rem;
    margin-right: 14px;
    flex-shrink: 0;
    font-family: var(--font-outfit);
}

.step-content h3 {
    font-size: 0.95rem;
    font-weight: 500;
    margin-bottom: 4px;
    color: var(--text-primary);
}

.step-content p {
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.4;
}

.step-content strong {
    color: var(--text-primary);
    font-weight: 500;
}

/* Footer styling */
.footer {
    margin-top: 24px;
    font-size: 0.75rem;
    color: rgba(255, 255, 255, 0.3);
    text-align: center;
}

/* Responsive adjustments */
@media (max-width: 480px) {
    .card {
        padding: 32px 20px;
        border-radius: 24px;
    }
    .brand-section {
        margin-bottom: 28px;
    }
    .logo-wrapper {
        width: 90px;
        height: 90px;
    }
    .app-title {
        font-size: 1.75rem;
    }
    .download-btn {
        padding: 14px 22px;
    }
}