body {
    background-color: #F7FAFC;
    color: #1F2937;
    font-family: 'Inter', Arial, sans-serif;
    transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    background-image: 
        radial-gradient(circle, rgba(0, 0, 0, 0.1) 1px, transparent 1px),
        linear-gradient(to bottom, rgba(255,255,255,0.8) 0%, rgba(255,255,255,0) 100px);
    background-size: 20px 20px, 100% 100%;
    min-height: 100vh;
    overflow-x: hidden;
}

body.dark {
    background-color: #1F2937;
    color: #E5E7EB;
    background-image: 
        radial-gradient(circle, rgba(255, 255, 255, 0.05) 1px, transparent 1px),
        linear-gradient(to bottom, rgba(0,0,0,0.5) 0%, rgba(0,0,0,0) 100px);
}

header h1 {
    font-size: 4rem;
    font-weight: 800;
    background: linear-gradient(135deg, #2D9C7F, #70D1FF, #A78BFA);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: 
        float 3s ease-in-out infinite,
        gradientShift 8s ease infinite alternate;
    text-shadow: 0 2px 10px rgba(45, 156, 127, 0.2);
    position: relative;
    margin-bottom: 2rem;
}

header h1::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 4px;
    background: linear-gradient(90deg, #2D9C7F, #70D1FF);
    border-radius: 2px;
    animation: widthPulse 3s ease infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

@keyframes gradientShift {
    0% {
        background-position: 0% 50%;
    }
    100% {
        background-position: 100% 50%;
    }
}

@keyframes widthPulse {
    0%, 100% {
        width: 100px;
    }
    50% {
        width: 150px;
    }
}

footer {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: rgba(0, 0, 0, 0.2);
    padding: 15px 0;
    text-align: center;
    font-size: 0.9rem;
    z-index: 2;
    backdrop-filter: blur(10px);
    transform: translateY(100%);
    animation: slideUp 0.5s 0.3s ease-out forwards;
}

@keyframes slideUp {
    to {
        transform: translateY(0);
    }
}

.btn {
    position: relative;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    padding: 14px 28px;
    border-radius: 50px;
    font-size: 1rem;
    text-decoration: none;
    box-shadow: 
        0 4px 15px rgba(45, 156, 127, 0.3),
        0 1px 3px rgba(0, 0, 0, 0.08);
    z-index: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 140px;
    background: linear-gradient(135deg, #2D9C7F 0%, #3AB196 30%, #70D1FF 70%, #8BD8FF 100%);
    color: white;
    font-weight: 600;
    cursor: pointer;
    border: none;
    outline: none;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    transform-style: preserve-3d;
    perspective: 500px;
}

.btn:hover {
    transform: translateY(-5px) scale(1.03) rotateX(10deg);
    box-shadow: 
        0 15px 25px rgba(45, 156, 127, 0.4),
        0 5px 10px rgba(0, 0, 0, 0.1);
    letter-spacing: 0.8px;
    background: linear-gradient(135deg, #2D9C7F 0%, #3AB196 40%, #70D1FF 80%, #8BD8FF 100%);
}

.btn:active {
    transform: scale(0.96) rotateX(5deg);
    box-shadow: 
        0 5px 10px rgba(45, 156, 127, 0.3),
        0 1px 3px rgba(0, 0, 0, 0.05);
    transition-duration: 0.1s;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, 
        transparent 0%, 
        rgba(255, 255, 255, 0.3) 50%, 
        transparent 100%);
    transition: all 0.7s cubic-bezier(0.19, 1, 0.22, 1);
}

.btn:hover::before {
    left: 100%;
}

.btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 8px;
    height: 8px;
    background: rgba(255, 255, 255, 0.7);
    border-radius: 50%;
    transform: translate(-50%, -50%) scale(0);
    transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.btn:active::after {
    transform: translate(-50%, -50%) scale(25);
    opacity: 0;
    transition-duration: 0.3s;
}

body.dark .btn {
    box-shadow: 
        0 4px 15px rgba(45, 156, 127, 0.4),
        0 1px 3px rgba(0, 0, 0, 0.1);
}

body.dark .btn:hover {
    box-shadow: 
        0 15px 30px rgba(45, 156, 127, 0.5),
        0 5px 15px rgba(0, 0, 0, 0.15);
}

body.dark .btn:active {
    box-shadow: 
        0 5px 12px rgba(45, 156, 127, 0.4),
        0 1px 3px rgba(0, 0, 0, 0.1);
}

.theme-toggle, .lang-toggle {
    padding: 12px;
    border-radius: 50%;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.25);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    position: relative;
    overflow: hidden;
}

.theme-toggle::before, .lang-toggle::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, rgba(255,255,255,0.3) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.theme-toggle:hover, .lang-toggle:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: scale(1.1) rotate(10deg);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.theme-toggle:hover::before, .lang-toggle:hover::before {
    opacity: 1;
}

.theme-toggle:active, .lang-toggle:active {
    transform: scale(0.95);
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
}

h3 {
    font-size: 1.8rem;
    font-weight: 700;
    margin: 1.5rem 0;
    position: relative;
    padding-bottom: 0.5rem;
    color: #1F2937;
    transition: all 0.3s ease;
}

body.dark h3 {
    color: #E5E7EB;
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2.5rem;
        transition: font-size 0.3s ease;
        margin-bottom: 1rem;
    }

    .btn {
        padding: 10px 20px;
        font-size: 0.85rem;
        min-width: 110px;
        transition: all 0.3s ease;
    }
    
    .theme-toggle, .lang-toggle {
        width: 40px;
        height: 40px;
        padding: 8px;
    }
    
    section {
        padding: 0 15px;
    }
    
    h3 {
        font-size: 1.5rem;
        margin: 1rem 0;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 2rem;
    }

    .btn {
        padding: 8px 16px;
        font-size: 0.8rem;
        min-width: 100px;
    }
    
    .theme-toggle, .lang-toggle {
        width: 36px;
        height: 36px;
        padding: 6px;
    }
    
    h3 {
        font-size: 1.3rem;
    }
    
    section {
        padding: 0 10px;
    }
    
    footer {
        padding: 10px 0;
        font-size: 0.8rem;
    }
}

@media (max-width: 360px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    .btn {
        padding: 6px 12px;
        font-size: 0.75rem;
        min-width: 90px;
    }
    
    .theme-toggle, .lang-toggle {
        width: 32px;
        height: 32px;
        padding: 4px;
    }
    
    h3 {
        font-size: 1.2rem;
    }
}

@media (max-width: 640px) {
    .flex.flex-wrap.justify-center.gap-4 {
        gap: 8px;
    }
    
    .btn {
        flex: 1 0 calc(50% - 8px);
        max-width: calc(50% - 8px);
    }
}

@media (max-width: 400px) {
    .btn {
        flex: 1 0 100%;
        max-width: 100%;
    }
}