:root {
    /* Light Mode Variables */
    --bg-color: #ffffff;
    --text-main: #000000;
    --text-muted: #666666;
    --accent-kakao: #FEE500;
    --accent-blue: #2563EB;
    --border-subtle: rgba(0, 0, 0, 0.1);
    --nav-bg: rgba(255, 255, 255, 0.8);
    --card-bg: rgba(0, 0, 0, 0.03);
    --smoke-color: rgba(0, 0, 0, 0.05);
    --font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

@media (prefers-color-scheme: dark) {
    :root {
        /* Dark Mode Variables */
        --bg-color: #000000;
        --text-main: #ffffff;
        --text-muted: #808080;
        --border-subtle: rgba(255, 255, 255, 0.1);
        --nav-bg: rgba(0, 0, 0, 0.7);
        --card-bg: rgba(255, 255, 255, 0.02);
        --smoke-color: rgba(255, 255, 255, 0.07);
    }
}

/* Global & Base */
* { box-sizing: border-box; margin: 0; padding: 0; }

body { 
    font-family: var(--font-family); 
    background-color: var(--bg-color); 
    color: var(--text-main); 
    line-height: 1.2; 
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
    zoom: 110%;
}

/* Navigation */
nav { 
    position: fixed; top: 0; width: 100%; height: 72px; 
    display: flex; align-items: center; justify-content: space-between; 
    padding: 0 40px; z-index: 1000; background: var(--nav-bg);
    backdrop-filter: blur(15px); -webkit-backdrop-filter: blur(15px);
    border-bottom: 1px solid var(--border-subtle);
}
.nav-brand { display: flex; align-items: center; gap: 12px; font-weight: 700; font-size: 20px; letter-spacing: -0.02em; }
.nav-logo { height: 24px; width: auto; transition: filter 0.3s ease; }

/* Buttons */
.btn-kakao, .btn-signout {
    padding: 10px 24px; border-radius: 8px; font-size: 14px; text-decoration: none;
    white-space: nowrap; transition: transform 0.2s, filter 0.2s, background 0.2s;
}
.btn-kakao { background: var(--accent-kakao); color: #000000; font-weight: 700; }
.btn-kakao:hover { transform: translateY(-1px); filter: brightness(0.9); }
.btn-signout { background: var(--card-bg); color: var(--text-main); font-weight: 600; border: 1px solid var(--border-subtle); }
.btn-signout:hover { background: rgba(128, 128, 128, 0.2); }

/* Hero Section */
.hero-container { padding: 180px 40px 100px; max-width: 1200px; margin: 0 auto; }
.hero-text { font-size: clamp(40px, 8vw, 90px); font-weight: 700; letter-spacing: -0.04em; line-height: 1; margin-bottom: 40px; }

/* Background Glow & Parallax */
.smoke-bg { position: fixed; bottom: 0; left: 0; width: 100%; height: 50vh; background: radial-gradient(circle at 50% 100%, var(--smoke-color) 0%, transparent 70%); z-index: -1; pointer-events: none; }
#parallax-bg { position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; z-index: -2; pointer-events: none; overflow: hidden; }
.bg-floating-logo { position: absolute; top: 0; left: 0; will-change: transform; filter: blur(var(--blur-amount)); opacity: var(--logo-opacity); }

@media (prefers-color-scheme: light) {
    .bg-floating-logo { filter: invert(1) blur(var(--blur-amount)); opacity: calc(var(--logo-opacity) * 0.7); }
}

/* Tab Section */
.container { max-width: 1000px; margin: 40px auto; padding: 0 40px; position: relative; }
.tab-nav { display: flex; gap: 24px; margin-bottom: 40px; border-bottom: 1px solid var(--border-subtle); padding-bottom: 12px; }
.tab-btn { background: none; border: none; font-size: 16px; color: var(--text-muted); cursor: pointer; font-weight: 500; transition: color 0.2s; position: relative; }
.tab-btn.active { color: var(--text-main); }
.tab-btn.active::after { content: ''; position: absolute; bottom: -13px; left: 0; width: 100%; height: 2px; background: var(--text-main); }

.tab-content { display: none; background: var(--card-bg); border: 1px solid var(--border-subtle); border-radius: 24px; padding: 48px; backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); animation: fadeIn 0.5s ease-out; }
.tab-content.active { display: block !important; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .hero-text { font-size: clamp(28px, 8vw, 40px); margin-bottom: 24px; }
    nav, .hero-container, .container { padding-left: 20px; padding-right: 20px; }
    .hero-container { padding-top: 120px; padding-bottom: 60px; }
    .tab-content { padding: 24px; }
    .tab-nav { gap: 16px; overflow-x: auto; white-space: nowrap; }
    body { zoom: 1 !important; }
}