:root {
    --bg-body: #f0f2f5;
    --bg-card: #fff;
    --text-primary: #1a1a2e;
    --text-secondary: #4a4a68;
    --accent: #ff9800;
    --accent-hover: #e65100;
    --header-bg: #1a1a2e;
    --shadow: 0 4px 20px rgba(0,0,0,0.08);
    --radius: 16px;
}

[data-theme="dark"] {
    --bg-body: #1a1a2e;
    --bg-card: #22223b;
    --text-primary: #fff;
    --text-secondary: #b2bec3;
    --header-bg: #0f3460;
    --shadow: 0 4px 20px rgba(0,0,0,0.3);
}

html {
    scroll-behavior: smooth;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, Arial, sans-serif;
    margin: 0;
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
    background: linear-gradient(135deg, #ffeb3b 0%, #8bc34a 50%, #4caf50 100%);
    background-attachment: fixed;
    transition: background 0.7s cubic-bezier(.4,0,.2,1), color 0.3s ease;
}

[data-theme="dark"] body {
    background: linear-gradient(135deg, #8bc34a 0%, #4caf50 50%, #2e7d32 100%);
}

body.theme-1 { background: linear-gradient(135deg, #8bc34a 0%, #4caf50 50%, #2e7d32 100%); }
body.theme-2 { background: linear-gradient(135deg, #2d3436 0%, #636e72 50%, #b2bec3 100%); }
body.theme-3 { background: linear-gradient(135deg, #000428 0%, #004e92 100%); }

header {
    background: var(--header-bg);
    color: #fff;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0,0,0,0.15);
}

nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    gap: 8px;
    max-width: 1200px;
    margin: 0 auto;
}

nav ul li a {
    color: rgba(255,255,255,0.85);
    text-decoration: none;
    font-weight: 500;
    padding: 18px 24px;
    display: block;
    transition: all 0.25s ease;
    border-bottom: 3px solid transparent;
}

nav ul li a:hover {
    color: #fff;
    background: rgba(255,255,255,0.05);
    border-bottom-color: var(--accent);
}

main {
    max-width: 800px;
    margin: 40px auto 80px auto;
    padding: 0 20px;
}

.card {
    background: var(--bg-card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 40px;
    margin-bottom: 30px;
    transition: transform 0.3s ease, box-shadow 0.3s ease, background 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
}

#home {
    text-align: center;
    padding: 60px 40px;
    background: linear-gradient(135deg, #8a2be2 0%, #4b0082 100%);
    color: #fff;
    border-radius: var(--radius);
}

#home h1 {
    font-size: 2.8rem;
    margin: 0 0 16px 0;
    font-weight: 700;
}

#home p {
    font-size: 1.2rem;
    opacity: 0.9;
    margin: 0;
}

#about h2, #contact h2 {
    color: var(--text-primary);
    margin-top: 0;
    font-size: 1.8rem;
}

#about h2::after, #contact h2::after {
    content: '';
    display: block;
    width: 50px;
    height: 4px;
    background: var(--accent);
    border-radius: 2px;
    margin-top: 10px;
}

.button {
    display: inline-block;
    margin-top: 24px;
    padding: 14px 36px;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.25s ease;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(255, 152, 0, 0.35);
}

.button:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 152, 0, 0.45);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.contact-info p {
    margin: 0;
    display: flex;
    align-items: center;
    gap: 10px;
}

.contact-info a {
    color: var(--accent);
    text-decoration: none;
}

.contact-info a:hover {
    text-decoration: underline;
}

footer {
    background: var(--header-bg);
    color: rgba(255,255,255,0.7);
    text-align: center;
    padding: 24px 0;
    font-size: 0.9rem;
    transition: background 0.3s ease;
}

@media (max-width: 600px) {
    nav ul {
        flex-direction: column;
        text-align: center;
    }
    
    nav ul li a {
        padding: 14px;
    }
    
    #home {
        padding: 40px 24px;
    }
    
    #home h1 {
        font-size: 2rem;
    }
    
    .card {
        padding: 24px;
    }
}

.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

#theme-btn {
    cursor: pointer;
    font-size: 1.2rem;
    transition: transform 0.3s ease;
}

#theme-btn:hover {
    transform: scale(1.2);
}

#current-time {
    font-weight: 600;
    color: var(--accent);
    margin-top: 8px;
}