/* ==================== 全局變量 ==================== */
:root {
    /* 主題顏色 */
    --color-bg-dark: #0a0a0a;
    --color-text-light: #ffffff;
    --color-text-gray: #a0a0a0;
    
    /* Legend 主題 - 金紫色 */
    --legend-gradient-start: #ffd700;
    --legend-gradient-end: #9333ea;
    --legend-glow: rgba(255, 215, 0, 0.3);
    
    /* Core 主題 - 橙色 */
    --core-gradient-start: #ff6b35;
    --core-gradient-end: #f7931e;
    --core-glow: rgba(255, 107, 53, 0.3);
    
    /* Ultimate Code 主題 - 藍色 */
    --ultimate-code-gradient-start: #00d4ff;
    --ultimate-code-gradient-end: #0066ff;
    --ultimate-code-glow: rgba(0, 212, 255, 0.3);
    
    /* Ultimate 主題 - 紫粉色 */
    --ultimate-gradient-start: #a855f7;
    --ultimate-gradient-end: #ec4899;
    --ultimate-glow: rgba(168, 85, 247, 0.3);
    
    /* Fast 主題 - 紅色 */
    --fast-gradient-start: #ff3366;
    --fast-gradient-end: #ff0055;
    --fast-glow: rgba(255, 51, 102, 0.3);
    
    /* Pro 主題 - 綠色 */
    --pro-gradient-start: #00ff88;
    --pro-gradient-end: #00aa55;
    --pro-glow: rgba(0, 255, 136, 0.3);
    
    /* Thinking 主題 - 青綠色 */
    --thinking-gradient-start: #06b6d4;
    --thinking-gradient-end: #10b981;
    --thinking-glow: rgba(6, 182, 212, 0.3);
    
    /* 字體 */
    --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', sans-serif;
    --font-display: 'Arial Black', sans-serif;
    
    /* 間距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* 動畫 */
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: all 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* ==================== 全局樣式 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    overflow-x: hidden;
}

body {
    font-family: var(--font-main);
    background: var(--color-bg-dark);
    color: var(--color-text-light);
    overflow-x: hidden;
    line-height: 1.6;
}

::selection {
    background: rgba(255, 255, 255, 0.2);
    color: var(--color-text-light);
}

/* ==================== 粒子背景 ==================== */
#particles-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
}

/* ==================== 導航欄 ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 4rem;
    background: rgba(10, 10, 10, 0.8);
    backdrop-filter: blur(10px);
    z-index: 1000;
    transition: var(--transition-smooth);
}

.navbar.scrolled {
    padding: 1rem 4rem;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: bold;
    background: linear-gradient(135deg, #ffd700, #00d4ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 2px;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-link {
    color: var(--color-text-gray);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition-smooth);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #ffd700, #00d4ff);
    transition: var(--transition-smooth);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-text-light);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* ==================== 滾動進度條 ==================== */
.scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, #ffd700, #9333ea, #00d4ff, #ff3366, #00ff88);
    z-index: 1001;
    transform-origin: left;
    transition: transform 0.1s linear;
}

/* ==================== 通用區塊樣式 ==================== */
.section {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg) var(--spacing-md);
    overflow: hidden;
}

/* ==================== Hero Section ==================== */
.hero-section {
    background: radial-gradient(circle at 50% 50%, rgba(147, 51, 234, 0.1) 0%, transparent 50%);
}

.hero-content {
    text-align: center;
    z-index: 10;
    max-width: 1200px;
}

.hero-badge {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 50px;
    font-size: 0.9rem;
    letter-spacing: 3px;
    margin-bottom: 2rem;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(3rem, 10vw, 8rem);
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 1rem;
    letter-spacing: -2px;
}

.title-line {
    display: block;
}

.gradient-text {
    background: linear-gradient(135deg, #ffd700, #9333ea, #00d4ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradient-shift 3s ease infinite;
    background-size: 200% 200%;
}

@keyframes gradient-shift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.hero-subtitle {
    font-size: clamp(1.2rem, 3vw, 1.8rem);
    color: var(--color-text-gray);
    margin-bottom: 3rem;
    letter-spacing: 1px;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 4rem;
    margin-top: 4rem;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 3rem;
    font-weight: bold;
    background: linear-gradient(135deg, #ffffff, #a0a0a0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--color-text-gray);
    margin-top: 0.5rem;
    letter-spacing: 1px;
}

/* ==================== 滾動指示器 ==================== */
.scroll-indicator {
    position: absolute;
    bottom: 3rem;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    z-index: 10;
}

.mouse {
    width: 28px;
    height: 45px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 15px;
    position: relative;
    margin: 0 auto 1rem;
}

.wheel {
    width: 4px;
    height: 8px;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 2px;
    position: absolute;
    top: 8px;
    left: 50%;
    transform: translateX(-50%);
    animation: scroll-wheel 1.5s ease-in-out infinite;
}

@keyframes scroll-wheel {
    0%, 100% { top: 8px; opacity: 1; }
    50% { top: 20px; opacity: 0.3; }
}

.scroll-indicator p {
    font-size: 0.85rem;
    color: var(--color-text-gray);
    letter-spacing: 1px;
}

/* ==================== 模型區塊通用樣式 ==================== */
.model-section {
    position: relative;
}

.model-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    opacity: 0.05;
    pointer-events: none;
}

.model-content {
    max-width: 1400px;
    width: 100%;
    z-index: 10;
    padding: 2rem;
}

.model-badge {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 2px;
    margin-bottom: 2rem;
    text-transform: uppercase;
    border: 1px solid rgba(255, 255, 255, 0.18);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

.model-title {
    font-family: var(--font-display);
    font-size: clamp(2.5rem, 7vw, 5rem);
    font-weight: 900;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.model-name {
    display: block;
}

.model-version {
    display: block;
    font-size: 0.5em;
    opacity: 0.6;
    margin-top: 0.5rem;
}

.model-description {
    font-size: clamp(1rem, 2vw, 1.3rem);
    color: var(--color-text-gray);
    margin-bottom: 3rem;
    max-width: 800px;
    line-height: 1.8;
}

.model-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

/* BaiLu 系列特殊佈局：5 個卡片（第一行 3 個，第二行 2 個居中） */
.bailu-grid {
    grid-template-columns: repeat(3, 1fr);
}

.bailu-grid .feature-card:nth-child(4),
.bailu-grid .feature-card:nth-child(5) {
    grid-column: span 1;
}

.bailu-grid .feature-card:nth-child(4) {
    grid-column-start: 1;
}

.bailu-grid .feature-card:nth-child(5) {
    grid-column-start: 2;
}

@media (max-width: 1024px) {
    .bailu-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .bailu-grid .feature-card:nth-child(4),
    .bailu-grid .feature-card:nth-child(5) {
        grid-column: span 1;
    }
    
    .bailu-grid .feature-card:nth-child(5) {
        grid-column: 1 / -1;
        max-width: 50%;
        margin: 0 auto;
    }
}

@media (max-width: 768px) {
    .bailu-grid {
        grid-template-columns: 1fr;
    }
    
    .bailu-grid .feature-card:nth-child(n) {
        grid-column: span 1;
    }
    
    .bailu-grid .feature-card:nth-child(5) {
        max-width: 100%;
    }
}

.feature-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 20px;
    padding: 2rem;
    transition: var(--transition-smooth);
    cursor: pointer;
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

.feature-card:hover {
    transform: translateY(-10px);
    background: rgba(255, 255, 255, 0.05);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    filter: grayscale(20%);
}

.feature-icon svg {
    width: 48px;
    height: 48px;
    stroke-width: 2;
    transition: var(--transition-smooth);
}

.feature-card:hover .feature-icon svg {
    transform: scale(1.1);
    filter: drop-shadow(0 0 8px currentColor);
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.8rem;
    font-weight: 700;
}

.feature-card p {
    color: var(--color-text-gray);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ==================== Legend 主題 ==================== */
.legend-theme {
    background: radial-gradient(circle at 30% 50%, rgba(255, 215, 0, 0.05) 0%, transparent 50%);
}

.legend-theme .model-badge {
    background: linear-gradient(135deg, var(--legend-gradient-start), var(--legend-gradient-end));
    color: #000;
}

.legend-theme .model-title {
    color: var(--legend-gradient-start);
    text-shadow: 0 0 30px var(--legend-glow);
}

.legend-theme .model-background {
    background: radial-gradient(circle at 50% 50%, var(--legend-glow) 0%, transparent 70%);
}

.legend-theme .feature-card:hover {
    border-color: var(--legend-gradient-start);
    box-shadow: 0 20px 60px var(--legend-glow);
}

/* ==================== Core 主題 ==================== */
.core-theme {
    background: radial-gradient(circle at 70% 50%, rgba(255, 107, 53, 0.05) 0%, transparent 50%);
}

.core-theme .model-badge {
    background: linear-gradient(135deg, var(--core-gradient-start), var(--core-gradient-end));
    color: #fff;
}

.core-theme .model-title {
    color: var(--core-gradient-start);
    text-shadow: 0 0 30px var(--core-glow);
}

.core-theme .model-background {
    background: radial-gradient(circle at 50% 50%, var(--core-glow) 0%, transparent 70%);
}

.core-theme .feature-card:hover {
    border-color: var(--core-gradient-start);
    box-shadow: 0 20px 60px var(--core-glow);
}

/* ==================== Ultimate Code 主題 ==================== */
.ultimate-code-theme {
    background: radial-gradient(circle at 30% 50%, rgba(0, 212, 255, 0.05) 0%, transparent 50%);
}

.ultimate-code-theme .model-badge {
    background: linear-gradient(135deg, var(--ultimate-code-gradient-start), var(--ultimate-code-gradient-end));
    color: #fff;
}

.ultimate-code-theme .model-title {
    color: var(--ultimate-code-gradient-start);
    text-shadow: 0 0 30px var(--ultimate-code-glow);
}

.ultimate-code-theme .model-background {
    background: radial-gradient(circle at 50% 50%, var(--ultimate-code-glow) 0%, transparent 70%);
}

.ultimate-code-theme .feature-card:hover {
    border-color: var(--ultimate-code-gradient-start);
    box-shadow: 0 20px 60px var(--ultimate-code-glow);
}

/* ==================== Ultimate 主題 ==================== */
.ultimate-theme {
    background: radial-gradient(circle at 70% 50%, rgba(168, 85, 247, 0.05) 0%, transparent 50%);
}

.ultimate-theme .model-badge {
    background: linear-gradient(135deg, var(--ultimate-gradient-start), var(--ultimate-gradient-end));
    color: #fff;
}

.ultimate-theme .model-title {
    color: var(--ultimate-gradient-start);
    text-shadow: 0 0 30px var(--ultimate-glow);
}

.ultimate-theme .model-background {
    background: radial-gradient(circle at 50% 50%, var(--ultimate-glow) 0%, transparent 70%);
}

.ultimate-theme .feature-card:hover {
    border-color: var(--ultimate-gradient-start);
    box-shadow: 0 20px 60px var(--ultimate-glow);
}

/* ==================== Fast 主題 ==================== */
.fast-theme {
    background: radial-gradient(circle at 70% 50%, rgba(255, 51, 102, 0.05) 0%, transparent 50%);
}

.fast-theme .model-badge {
    background: linear-gradient(135deg, var(--fast-gradient-start), var(--fast-gradient-end));
    color: #fff;
}

.fast-theme .model-title {
    color: var(--fast-gradient-start);
    text-shadow: 0 0 30px var(--fast-glow);
}

.fast-theme .model-background {
    background: radial-gradient(circle at 50% 50%, var(--fast-glow) 0%, transparent 70%);
}

.fast-theme .feature-card:hover {
    border-color: var(--fast-gradient-start);
    box-shadow: 0 20px 60px var(--fast-glow);
}

/* ==================== Thinking 主題 ==================== */
.thinking-theme {
    background: radial-gradient(circle at 50% 50%, rgba(6, 182, 212, 0.05) 0%, transparent 50%);
}

.thinking-theme .model-badge {
    background: linear-gradient(135deg, var(--thinking-gradient-start), var(--thinking-gradient-end));
    color: #fff;
}

.thinking-theme .model-title {
    color: var(--thinking-gradient-start);
    text-shadow: 0 0 30px var(--thinking-glow);
}

.thinking-theme .model-background {
    background: radial-gradient(circle at 50% 50%, var(--thinking-glow) 0%, transparent 70%);
}

.thinking-theme .feature-card:hover {
    border-color: var(--thinking-gradient-start);
    box-shadow: 0 20px 60px var(--thinking-glow);
}

/* ==================== Pro 主題 ==================== */
.pro-theme {
    background: radial-gradient(circle at 30% 50%, rgba(0, 255, 136, 0.05) 0%, transparent 50%);
}

.pro-theme .model-badge {
    background: linear-gradient(135deg, var(--pro-gradient-start), var(--pro-gradient-end));
    color: #000;
}

.pro-theme .model-title {
    color: var(--pro-gradient-start);
    text-shadow: 0 0 30px var(--pro-glow);
}

.pro-theme .model-background {
    background: radial-gradient(circle at 50% 50%, var(--pro-glow) 0%, transparent 70%);
}

.pro-theme .feature-card:hover {
    border-color: var(--pro-gradient-start);
    box-shadow: 0 20px 60px var(--pro-glow);
}

/* ==================== Demo 主題 ==================== */
.demo-theme {
    background: radial-gradient(circle at 50% 50%, rgba(138, 43, 226, 0.05) 0%, transparent 50%);
}

.demo-theme .model-badge {
    background: linear-gradient(135deg, #8a2be2, #4b0082);
    color: #fff;
}

.demo-theme .model-title {
    color: #8a2be2;
    text-shadow: 0 0 30px rgba(138, 43, 226, 0.3);
}

.demo-theme .model-background {
    background: radial-gradient(circle at 50% 50%, rgba(138, 43, 226, 0.1) 0%, transparent 70%);
}

.demo-theme .feature-card:hover {
    border-color: #8a2be2;
    box-shadow: 0 20px 60px rgba(138, 43, 226, 0.3);
}

.demo-theme .feature-icon svg {
    stroke: #8a2be2;
}

/* ==================== Demo CTA ==================== */
.demo-cta {
    text-align: center;
    margin-top: 4rem;
}

.demo-button {
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    padding: 1.2rem 3rem;
    background: linear-gradient(135deg, #8a2be2, #4b0082);
    border: 2px solid rgba(138, 43, 226, 0.5);
    border-radius: 50px;
    color: #fff;
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 700;
    transition: var(--transition-smooth);
    box-shadow: 0 10px 40px rgba(138, 43, 226, 0.3);
    position: relative;
    overflow: hidden;
}

.demo-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.6s ease;
}

.demo-button:hover::before {
    left: 100%;
}

.demo-button svg {
    width: 24px;
    height: 24px;
    transition: var(--transition-smooth);
    flex-shrink: 0;
}

.demo-button svg:first-child {
    transition: transform 0.3s ease;
}

.demo-button .arrow-icon {
    transition: transform 0.3s ease, opacity 0.3s ease;
    opacity: 0.8;
}

.demo-button:hover {
    transform: translateY(-5px) scale(1.05);
    box-shadow: 0 20px 60px rgba(138, 43, 226, 0.5);
    border-color: #8a2be2;
}

.demo-button:hover svg:first-child {
    transform: scale(1.2);
}

.demo-button:hover .arrow-icon {
    transform: translateX(8px);
    opacity: 1;
}

.demo-button:active {
    transform: translateY(-3px) scale(1.02);
}

.demo-note {
    margin-top: 1.5rem;
    font-size: 0.9rem;
    color: var(--color-text-gray);
    font-style: italic;
}

/* ==================== Footer Section ==================== */
.footer-section {
    background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.02) 0%, transparent 50%);
    text-align: center;
}

.footer-content {
    max-width: 800px;
    z-index: 10;
}

.footer-content h2 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    margin-bottom: 1rem;
}

.footer-content > p {
    font-size: 1.2rem;
    color: var(--color-text-gray);
    margin-bottom: 3rem;
}

.footer-logo {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin: 3rem 0;
}

.logo-text {
    font-family: var(--font-display);
    font-size: 3rem;
    font-weight: 900;
    letter-spacing: 2px;
}

.footer-link {
    display: inline-flex;
    align-items: center;
    gap: 0.8rem;
    padding: 1rem 2.5rem;
    margin: 2rem 0;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 50px;
    color: var(--color-text-light);
    text-decoration: none;
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition-smooth);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    position: relative;
    overflow: hidden;
}

.footer-link::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: left 0.5s ease;
}

.footer-link:hover::before {
    left: 100%;
}

.footer-link svg {
    width: 20px;
    height: 20px;
    transition: var(--transition-smooth);
    flex-shrink: 0;
}

.footer-link svg:first-child {
    transition: transform 0.3s ease;
}

.footer-link .arrow-icon {
    transition: transform 0.3s ease, opacity 0.3s ease;
    opacity: 0.7;
}

.footer-link span {
    position: relative;
    z-index: 1;
}

.footer-link:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: #00d4ff;
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 212, 255, 0.4);
}

.footer-link:hover svg:first-child {
    transform: translateX(-3px) translateY(-3px);
}

.footer-link:hover .arrow-icon {
    transform: translateX(5px);
    opacity: 1;
}

.footer-link:active {
    transform: translateY(-3px);
}

.footer-copyright {
    font-size: 0.9rem;
    color: var(--color-text-gray);
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* ==================== 返回頂部按鈕 ==================== */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 56px;
    height: 56px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 50%;
    color: var(--color-text-light);
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-smooth);
    z-index: 9999;
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.back-to-top::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.4s ease, height 0.4s ease;
}

.back-to-top:hover::before {
    width: 100%;
    height: 100%;
}

.back-to-top svg {
    width: 24px;
    height: 24px;
    transition: transform 0.3s ease;
    position: relative;
    z-index: 1;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    animation: bounceIn 0.6s ease;
}

@keyframes bounceIn {
    0% {
        opacity: 0;
        transform: scale(0.3) rotate(180deg);
    }
    50% {
        opacity: 1;
        transform: scale(1.1) rotate(-10deg);
    }
    70% {
        transform: scale(0.9) rotate(5deg);
    }
    100% {
        transform: scale(1) rotate(0);
    }
}

.back-to-top:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.3);
}

.back-to-top:hover svg {
    transform: translateY(-3px);
    animation: arrowPulse 1s ease infinite;
}

@keyframes arrowPulse {
    0%, 100% {
        transform: translateY(-3px);
    }
    50% {
        transform: translateY(-8px);
    }
}

.back-to-top:active {
    transform: translateY(-3px) scale(0.95);
}