:root {
    --bg-dark: #0a0a16;
    --card-bg: rgba(255, 255, 255, 0.05);
    --card-border: rgba(255, 255, 255, 0.1);
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --primary: #9d4edd;
    --primary-glow: rgba(157, 78, 221, 0.4);
    --secondary: #240046;
    --accent: #3a86c8;
    --font-outfit: 'Outfit', 'Noto Sans TC', sans-serif;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

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

/* Aurora animations */
.aurora-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    overflow: hidden;
    background: radial-gradient(circle at 50% 50%, #100b26 0%, var(--bg-dark) 100%);
}

.aurora-glow {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.4;
    animation: rotateGlow 20s infinite linear;
}

.aurora-glow-1 {
    width: 50vw;
    height: 50vw;
    background: radial-gradient(circle, rgba(157, 78, 221, 0.6) 0%, rgba(0,0,0,0) 70%);
    top: -10%;
    left: -10%;
}

.aurora-glow-2 {
    width: 60vw;
    height: 60vw;
    background: radial-gradient(circle, rgba(58, 134, 200, 0.5) 0%, rgba(0,0,0,0) 70%);
    bottom: -15%;
    right: -10%;
    animation-direction: reverse;
    animation-duration: 25s;
}

@keyframes rotateGlow {
    0% { transform: translate(0, 0) rotate(0deg); }
    50% { transform: translate(50px, 30px) rotate(180deg); }
    100% { transform: translate(0, 0) rotate(360deg); }
}

.app-container {
    width: 100%;
    max-width: 600px;
    padding: 24px;
    z-index: 1;
    transition: opacity 0.15s ease-in-out;
}

/* Glassmorphism Card Style */
.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--card-border);
    border-radius: 24px;
    padding: 32px;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
    transition: var(--transition);
}

.glass-card:hover {
    border-color: rgba(255, 255, 255, 0.15);
    box-shadow: 0 12px 40px 0 rgba(157, 78, 221, 0.15);
    transform: translateY(-2px);
}

/* Interactive elements */
button {
    font-family: var(--font-outfit);
    cursor: pointer;
    border: none;
    border-radius: 12px;
    transition: var(--transition);
}

button:active {
    transform: scale(0.97);
}

.input-field {
    width: 100%;
    padding: 12px 16px;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--card-border);
    border-radius: 12px;
    color: var(--text-primary);
    font-family: var(--font-outfit);
    outline: none;
    transition: var(--transition);
}

.input-field:focus {
    border-color: var(--primary);
    box-shadow: 0 0 8px var(--primary-glow);
}

@media (max-width: 480px) {
    .glass-card { padding: 20px 16px; }
    .app-container { padding: 12px; }
    .btn-group-responsive {
        flex-direction: column !important;
        gap: 8px !important;
    }
    .btn-responsive {
        width: 100% !important;
        flex: none !important;
    }
}