/* ===================================
   CSS Custom Properties (Variables)
   =================================== */
:root {
    /* Colors */
    --color-primary: #6366f1;
    --color-primary-dark: #4f46e5;
    --color-secondary: #10b981;
    --color-accent: #f59e0b;
    
    --color-bg-primary: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-bg-card: #1e293b;
    
    --color-text-primary: #f1f5f9;
    --color-text-secondary: #cbd5e1;
    --color-text-muted: #94a3b8;
    
    --color-border: #334155;
    
    /* Typography */
    --font-primary: 'Poppins', sans-serif;
    --font-code: 'Fira Code', monospace;
    
    --font-size-base: 1rem;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;
    
    /* Layout */
    --container-width: 1200px;
    --border-radius: 0.5rem;
    --border-radius-lg: 1rem;
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.2);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.3);
}

/* ===================================
   Reset & Base Styles
   =================================== */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    overflow-x: hidden;
}

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

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-base);
}

ul {
    list-style: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* ===================================
   Utility Classes
   =================================== */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-3xl) 0;
}

.section__title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section__subtitle {
    text-align: center;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-xl);
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: var(--font-size-base);
    font-weight: 500;
    border-radius: var(--border-radius);
    transition: var(--transition-base);
    text-align: center;
}

.btn--primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
}

.btn--primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn--secondary {
    background: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

.btn--secondary:hover {
    background: var(--color-primary);
    color: white;
}

.btn--full {
    width: 100%;
}

.btn--sm {
    padding: 0.5rem 1rem;
    font-size: var(--font-size-sm);
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.35rem 0.75rem;
    font-size: var(--font-size-sm);
    font-weight: 600;
    border-radius: 50px;
}

.badge--success {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--color-secondary);
    border: 1px solid rgba(16, 185, 129, 0.2);
}

/* ===================================
   Header & Navigation
   =================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--color-border);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav__logo {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
}

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

.nav__menu {
    display: flex;
    gap: var(--spacing-lg);
}

.nav__link {
    color: var(--color-text-secondary);
    font-weight: 500;
    position: relative;
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: var(--transition-base);
}

.nav__link:hover {
    color: var(--color-primary);
}

.nav__link:hover::after {
    width: 100%;
}

.nav__toggle,
.nav__close {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--color-text-primary);
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 70px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 80% 80%, rgba(16, 185, 129, 0.1) 0%, transparent 50%);
    z-index: -1;
}

.hero__content {
    max-width: 700px;
}

.hero__greeting {
    font-size: var(--font-size-lg);
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.hero__title {
    font-size: var(--font-size-5xl);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
}

.hero__subtitle {
    font-size: var(--font-size-3xl);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.hero__description {
    font-size: var(--font-size-lg);
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

.hero__buttons {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.hero__social {
    display: flex;
    gap: var(--spacing-md);
}

.social__link {
    width: 45px;
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-bg-secondary);
    border-radius: var(--border-radius);
    color: var(--color-text-primary);
    font-size: 1.25rem;
    transition: var(--transition-base);
}

.social__link:hover {
    background: var(--color-primary);
    transform: translateY(-3px);
}

/* ===================================
   About Section
   =================================== */
.about__container {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-2xl);
    align-items: start;
}

.about__image {
    position: relative;
}

.about__img {
    width: 100%;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-xl);
}

.about__description {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

.about__tabs {
    display: flex;
    gap: var(--spacing-md);
    margin: var(--spacing-xl) 0 var(--spacing-lg);
    border-bottom: 2px solid var(--color-border);
}

.tab__button {
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text-muted);
    background: none;
    border: none;
    cursor: pointer;
    transition: var(--transition-base);
    position: relative;
}

.tab__button::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: var(--transition-base);
}

.tab__button--active {
    color: var(--color-primary);
}

.tab__button--active::after {
    width: 100%;
}

.tab__content {
    display: none;
}

.tab__content--active {
    display: block;
}

.skills__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
}

.skill__category-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

.skill__list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.skill__item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-text-secondary);
    padding: var(--spacing-xs) 0;
}

.skill__item i {
    color: var(--color-primary);
    font-size: 1.25rem;
}

.education__list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.education__item {
    padding: var(--spacing-lg);
    background: var(--color-bg-secondary);
    border-radius: var(--border-radius);
    border-left: 3px solid var(--color-primary);
}

.education__degree {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xs);
}

.education__school {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
}

.education__year {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

/* ===================================
   Experience Section
   =================================== */
.experience {
    background: var(--color-bg-secondary);
}

.experience__card {
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-xl);
    background: var(--color-bg-card);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
}

.experience__header {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.experience__title {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-xs);
}

.experience__company {
    font-size: var(--font-size-lg);
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.experience__location,
.experience__duration {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.experience__responsibilities {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.experience__responsibilities li {
    color: var(--color-text-secondary);
    padding-left: var(--spacing-lg);
    position: relative;
    line-height: 1.8;
}

.experience__responsibilities li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: bold;
}

/* ===================================
   Projects Section
   =================================== */
.projects__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.projects__grid--personal {
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
}

.project__card {
    background: var(--color-bg-card);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    border: 1px solid var(--color-border);
    transition: var(--transition-base);
    display: flex;
    flex-direction: column;
}

.project__card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--color-primary);
}

.project__card--professional {
    border-left: 3px solid var(--color-primary);
}

.project__image {
    position: relative;
    overflow: hidden;
    aspect-ratio: 16 / 9;
    background: var(--color-bg-secondary);
}

.project__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition-base);
}

.project__card:hover .project__image img {
    transform: scale(1.05);
}

.project__overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 23, 42, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition-base);
}

.project__card:hover .project__overlay {
    opacity: 1;
}

.project__link {
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--color-primary);
    color: white;
    border-radius: var(--border-radius);
    font-weight: 500;
    transition: var(--transition-base);
}

.project__link:hover {
    background: var(--color-primary-dark);
}

.project__content {
    padding: var(--spacing-lg);
    flex: 1;
    display: flex;
    flex-direction: column;
}

.project__title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
}

.project__description {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
    flex: 1;
}

.project__bullet-list {
    list-style-type: none;
    padding-left: 0;
    margin-bottom: var(--spacing-md);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.6;
    flex: 1;
}

.project__bullet-list li {
    margin-bottom: 0.5rem;
    position: relative;
    padding-left: 1.25rem;
}

.project__bullet-list li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--color-primary);
}

.project__tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.tech__tag {
    padding: 0.375rem 0.75rem;
    background: rgba(99, 102, 241, 0.1);
    color: var(--color-primary);
    border-radius: var(--border-radius);
    font-size: var(--font-size-sm);
    font-family: var(--font-code);
}

/* ===================================
   Contact Section
   =================================== */
.contact {
    background: var(--color-bg-secondary);
}

.contact__container {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: var(--spacing-2xl);
    max-width: 1000px;
    margin: 0 auto;
}

.contact__info-title {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-lg);
}

.contact__item {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.contact__icon {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-bg-card);
    border-radius: var(--border-radius);
    color: var(--color-primary);
    font-size: 1.25rem;
    flex-shrink: 0;
}

.contact__item h4 {
    margin-bottom: var(--spacing-xs);
    font-size: var(--font-size-base);
}

.contact__item a {
    color: var(--color-text-secondary);
    transition: var(--transition-base);
}

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

.contact__item p {
    color: var(--color-text-secondary);
}

.contact__social {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.contact__form {
    background: var(--color-bg-card);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border);
}

.form__group {
    margin-bottom: var(--spacing-md);
}

.form__input,
.form__textarea {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    color: var(--color-text-primary);
    font-family: inherit;
    font-size: var(--font-size-base);
    transition: var(--transition-base);
}

.form__input:focus,
.form__textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

.form__textarea {
    resize: vertical;
    min-height: 150px;
}

.form__message {
    display: none;
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background: rgba(16, 185, 129, 0.1);
    border-radius: var(--border-radius);
    color: var(--color-secondary);
    text-align: center;
    font-weight: 500;
    transition: var(--transition-base);
}

/* ===================================
   Footer
   =================================== */
.footer {
    padding: var(--spacing-xl) 0;
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
}

.footer__text {
    text-align: center;
    color: var(--color-text-muted);
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 968px) {
    :root {
        --font-size-5xl: 2.5rem;
        --font-size-4xl: 2rem;
        --font-size-3xl: 1.5rem;
    }
    
    .nav__menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 400px;
        height: 100vh;
        background: var(--color-bg-secondary);
        flex-direction: column;
        padding: var(--spacing-3xl) var(--spacing-xl);
        transition: var(--transition-base);
        box-shadow: var(--shadow-xl);
    }
    
    .nav__menu.show-menu {
        right: 0;
    }
    
    .nav__toggle,
    .nav__close {
        display: block;
    }
    
    .nav__close {
        position: absolute;
        top: var(--spacing-lg);
        right: var(--spacing-lg);
    }
    
    .hero__title {
        font-size: var(--font-size-4xl);
    }
    
    .hero__buttons {
        flex-direction: column;
    }
    
    .about__container {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .skills__grid {
        grid-template-columns: 1fr;
    }
    
    .projects__grid,
    .projects__grid--personal {
        grid-template-columns: 1fr;
    }
    
    .contact__container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 576px) {
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .section {
        padding: var(--spacing-2xl) 0;
    }
    
    .hero__title {
        font-size: var(--font-size-3xl);
    }
    
    .section__title {
        font-size: var(--font-size-3xl);
    }
    
    .about__tabs {
        flex-direction: column;
        border-bottom: none;
    }
    
    .tab__button {
        text-align: left;
        border-bottom: 1px solid var(--color-border);
    }
}

/* ===================================
   Animations
   =================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}