/* =============================================
   Reset & Variables
   ============================================= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #64748b;
    --background: #ffffff;
    --surface: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --transition: all 0.3s ease;
    --header-bg: rgba(255, 255, 255, 0.95);
}

/* Dark mode */
[data-theme="dark"] {
    --primary-color: #3b82f6;
    --primary-dark: #60a5fa;
    --secondary-color: #94a3b8;
    --background: #0f172a;
    --surface: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
    --header-bg: rgba(15, 23, 42, 0.95);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    padding: 5rem 0;
    position: relative;
}

#about, #skills, #contact {
    padding: 5rem 2rem;
}

h2 {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.highlight {
    color: var(--primary-color);
}


/* =============================================
   Header & Navigation
   ============================================= */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--header-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

a.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

a.logo:hover {
    color: var(--text-primary);
}

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

.nav-links a {
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary-color);
}

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

/* Theme toggle */
.theme-toggle {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 42px;
    height: 42px;
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    margin-left: 1rem;
}

.theme-toggle:hover {
    border-color: var(--primary-color);
    transform: rotate(15deg);
}

/* Hamburger */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    position: relative;
    z-index: 1001;
}

.hamburger span {
    display: block;
    width: 26px;
    height: 2.5px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
    transform-origin: center;
}

.hamburger.active span:nth-child(1) {
    transform: translateY(7.5px) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.hamburger.active span:nth-child(3) {
    transform: translateY(-7.5px) rotate(-45deg);
}


/* =============================================
   Hero Section
   ============================================= */
#hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 80px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 60% at 50% 40%, rgba(37, 99, 235, 0.08) 0%, transparent 70%),
        radial-gradient(ellipse 40% 50% at 80% 80%, rgba(37, 99, 235, 0.05) 0%, transparent 70%),
        radial-gradient(ellipse 30% 40% at 20% 20%, rgba(124, 58, 237, 0.04) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Typewriter */
.typewriter-line {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    min-height: 2rem;
}

.typewriter-prefix {
    color: var(--text-secondary);
}

.typewriter-text {
    color: var(--primary-color);
    font-weight: 600;
}

.typewriter-cursor {
    color: var(--primary-color);
    font-weight: 300;
    animation: blink 1s step-end infinite;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

.cta-button {
    display: inline-block;
    padding: 1rem 2.5rem;
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    border-radius: var(--radius);
    transition: var(--transition);
}

.cta-button:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Hero bottom divider */
.hero-divider {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 80px;
    background: var(--surface);
    clip-path: polygon(0 40%, 100% 0, 100% 100%, 0 100%);
}


/* =============================================
   About Section
   ============================================= */
#about {
    background: var(--surface);
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
    align-items: center;
}

.about-text p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.stat {
    text-align: center;
    padding: 1.5rem;
    background: var(--background);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.stat:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}


/* =============================================
   Skills Section
   ============================================= */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.skill-category {
    background: var(--surface);
    padding: 2rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.skill-category:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.skill-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.skill-item {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.skill-name {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.skill-bar {
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.skill-fill {
    height: 100%;
    width: 0;
    border-radius: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--primary-dark));
    transition: width 1s ease 0.2s;
}

.skill-fill.visible {
    width: var(--skill-level);
}





/* =============================================
   Contact Section
   ============================================= */
#contact {
    background: var(--surface);
}

.contact-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.contact-content > p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    text-align: left;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
    font-family: inherit;
    background: var(--background);
    color: var(--text-primary);
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.submit-button {
    padding: 1rem 2rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.submit-button:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 3rem;
    flex-wrap: wrap;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-weight: 500;
    transition: var(--transition);
}

.contact-link:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}


/* =============================================
   Scroll-to-top Button
   ============================================= */
.scroll-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 48px;
    height: 48px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 1.4rem;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
}

.scroll-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.scroll-top:hover {
    background: var(--primary-dark);
    transform: translateY(-4px);
}


/* =============================================
   Footer
   ============================================= */
footer {
    background: var(--text-primary);
    color: var(--background);
    text-align: center;
    padding: 2rem;
}


/* =============================================
   Responsive
   ============================================= */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
        position: fixed;
        top: 1.2rem;
        right: 2rem;
        z-index: 2000;
    }

    .nav-links {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        height: 100dvh;
        background: var(--header-bg);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 2.5rem;
        opacity: 0;
        visibility: hidden;
        transition: opacity 0.3s ease, visibility 0s 0.3s;
        z-index: 1999;
        overflow-y: auto;
    }

    .nav-links.active {
        opacity: 1;
        visibility: visible;
        transition: opacity 0.3s ease, visibility 0s;
    }

    .nav-links a {
        font-size: 1.5rem;
    }

    .theme-toggle {
        position: fixed;
        top: 1.2rem;
        right: 5rem;
        z-index: 2000;
        margin-left: 0;
        margin-right: 0;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

    .tagline {
        font-size: 1.2rem;
    }

    .typewriter-line {
        font-size: 1.05rem;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .about-stats {
        grid-template-columns: 1fr;
    }

    .skills-grid {
        grid-template-columns: 1fr;
    }

    section {
        padding: 3rem 0;
    }

    #about, #skills, #contact {
        padding: 3rem 1rem;
    }

    .scroll-top {
        bottom: 1.5rem;
        right: 1.5rem;
        width: 42px;
        height: 42px;
        font-size: 1.2rem;
    }
}


/* =============================================
   Section Dividers (between surface/white sections)
   ============================================= */
#about::before,
#contact::before {
    content: '';
    position: absolute;
    top: -40px;
    left: 0;
    width: 100%;
    height: 40px;
    background: var(--surface);
    clip-path: polygon(0 100%, 100% 0, 100% 100%, 0 100%);
    pointer-events: none;
}

#about {
    padding-top: 6rem;
}

#contact {
    padding-top: 6rem;
}