* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    text-decoration: none;
    list-style: none;
}

:root {
    --primary-color: #0056b3; /* Biru */
    --secondary-color: #f1f5f9; /* Abu-abu sangat muda untuk latar */
    --text-color: #334155; /* Abu-abu gelap untuk teks */
    --white: #ffffff;
    --transition: 0.3s ease;

    /* Warna kartu/panel (kaca gelap) - default: Dark Mode */
    --card-bg: rgba(15, 23, 42, 0.7);
    --card-bg-solid: rgba(15, 23, 42, 0.9);
    --card-text: #ffffff;
    --card-text-muted: #cbd5e1;
    --overlay-color: rgba(15, 23, 42, 0.35);
    --heading-shadow: 2px 2px 5px rgba(0, 0, 0, 0.8);
}

body.light-mode {
    /* Warna kartu/panel saat Light Mode */
    --card-bg: rgba(255, 255, 255, 0.85);
    --card-bg-solid: rgba(255, 255, 255, 0.95);
    --card-text: #1e293b;
    --card-text-muted: #475569;
    --overlay-color: rgba(255, 255, 255, 0.55);
    --heading-shadow: 1px 1px 3px rgba(255, 255, 255, 0.9);
}

body::before {
    content: "";
    position: fixed;
    inset: 0;
    background-color: var(--overlay-color);
    transition: background-color var(--transition);
    z-index: -1;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--secondary-color);
    background-image: url('pexels-brett-sayles-5073493.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    color: var(--text-color);
    line-height: 1.6;
}

/* =========================================
   NAVBAR (HEADER)
========================================= */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.2rem 8%;
    background-color: rgba(15, 23, 42, 0.9);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--white);
}

.logo span {
    color: var(--primary-color);
}

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

.nav-links a {
    color: var(--white);
    font-weight: 400;
    transition: var(--transition);
}

.nav-links a:hover, 
.nav-links a.active {
    color: var(--primary-color);
    font-weight: 600;
}

/* =========================================
   HAMBURGER MENU (MOBILE)
========================================= */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 28px;
    height: 20px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 200;
}

.hamburger span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: var(--white);
    border-radius: 2px;
    transition: var(--transition);
}

.hamburger.active span:nth-child(1) {
    transform: translateY(8.5px) rotate(45deg);
}

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

.hamburger.active span:nth-child(3) {
    transform: translateY(-8.5px) rotate(-45deg);
}

/* =========================================
   THEME TOGGLE (DARK / LIGHT)
========================================= */
.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 1px solid rgba(255, 255, 255, 0.3);
    background: transparent;
    color: var(--white);
    font-size: 1.1rem;
    cursor: pointer;
    transition: var(--transition);
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.1);
}

.nav-controls {
    display: flex;
    align-items: center;
    gap: 1.2rem;
}

/* =========================================
   FADE-IN ON SCROLL
========================================= */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* =========================================
   BACK TO TOP BUTTON
========================================= */
.back-to-top {
    position: fixed;
    right: 1.5rem;
    bottom: 1.5rem;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    border: none;
    background-color: var(--primary-color);
    color: var(--white);
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    opacity: 0;
    visibility: hidden;
    transform: translateY(15px);
    transition: var(--transition);
    z-index: 150;
}

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

.back-to-top:hover {
    background-color: #004494;
}

/* =========================================
   TYPING EFFECT (HERO)
========================================= */
.typing-cursor {
    display: inline-block;
    margin-left: 2px;
    animation: blink 0.8s step-end infinite;
}

@keyframes blink {
    50% { opacity: 0; }
}

/* =========================================
   BUTTONS
========================================= */
.btn {
    display: inline-block;
    padding: 0.6rem 1.5rem;
    border-radius: 5px;
    font-weight: 600;
    transition: var(--transition);
    cursor: pointer;
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    background-color: #004494;
}

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

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

/* =========================================
   HOME 
========================================= */
.hero {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 4rem 8%;
    min-height: 80vh;
}

.hero-content {
    max-width: 800px;
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 15px;
    backdrop-filter: blur(5px);
}

.hero-content h3 {
    font-size: 1.2rem;
    font-weight: 400;
    color: var(--card-text-muted);
}

.hero-content h1 {
    font-size: 3rem;
    font-weight: 600;
    color: var(--card-text);
    margin: 0.5rem 0;
}

.hero-content h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--card-text-muted);
    margin-bottom: 1rem;
}

.hero-content p {
    margin-bottom: 2rem;
    font-size: 1rem;
    color: var(--card-text-muted);
}

.cta-buttons {
    display: flex;
    gap: 1rem;
}

.hero-image img {
    width: 320px;
    height: 320px;
    object-fit: cover;
    border-radius: 20px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

/* =========================================
   ABOUT 
========================================= */
.about-container {
    padding: 4rem 8%;
    max-width: 1200px;
    margin: auto;
}

.about-text h2, 
.skills-section h3, 
.projects-section h3,
.contact-header h2 {
    font-size: 2rem;
    color: var(--card-text);
    text-shadow: var(--heading-shadow);
    margin-bottom: 1rem;
    text-align: center;
}

.contact-header p {
    color: var(--card-text);
    text-shadow: var(--heading-shadow);
}

.about-description {
    background: var(--card-bg);
    backdrop-filter: blur(5px);
    color: var(--card-text);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
    text-align: center;
    margin-bottom: 3rem;
}

.about-description p {
    margin-bottom: 1rem;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.skill-card {
    background: var(--card-bg);
    backdrop-filter: blur(5px);
    color: var(--card-text);
    padding: 1.5rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
    border-bottom: 3px solid var(--primary-color);
    transition: var(--transition);
}

.skill-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
}

.skill-card h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--card-text);
}

.skill-card p {
    font-size: 0.9rem;
    color: var(--card-text-muted);
}

/* =========================================
   PROJECTS
========================================= */
.projects-section {
    margin-top: 4rem;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.project-card {
    background: var(--card-bg);
    backdrop-filter: blur(5px);
    color: var(--card-text);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
    border-left: 5px solid var(--primary-color);
    transition: var(--transition);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
}

.project-card h4 {
    font-size: 1.3rem;
    margin-bottom: 0.8rem;
    color: var(--card-text);
}

.project-card p {
    font-size: 1rem;
    color: var(--card-text-muted);
}

/* =========================================
CONTACT 
========================================= */
.contact-container {
    padding: 4rem 8%;
    max-width: 1000px;
    margin: auto;
}

.contact-header {
    text-align: center;
    margin-bottom: 3rem;
}

.contact-content {
    display: flex;
    gap: 3rem;
    justify-content: space-between;
}

.contact-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.info-card {
    background: var(--card-bg);
    backdrop-filter: blur(5px);
    color: var(--card-text);
    padding: 1.5rem;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
}

.info-card h4 {
    font-size: 1rem;
    color: var(--card-text-muted);
    margin-bottom: 0.3rem;
}

.info-card a {
    color: #38bdf8;
    font-weight: 600;
    font-size: 1.1rem;
    
}

.contact-form {
    flex: 1;
    background: var(--card-bg);
    backdrop-filter: blur(5px);
    color: var(--card-text);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
}

.contact-form h3 {
    margin-bottom: 1.5rem;
    color: var(--card-text);
}

.input-group {
    margin-bottom: 1.2rem;
}

.input-group input, 
.input-group textarea {
    width: 100%;
    padding: 10px 15px;
    border: 1px solid rgba(0, 0, 0, 0.03);
    border-radius: 5px;
    font-family: inherit;
    font-size: 1rem;
    outline: none;
    transition: var(--transition);

    /* Transparan seperti kaca */
    background: rgba(0, 0, 0, 0.03);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);

    /* Warna tulisan */
    color: var(--card-text);
}

.input-group input:focus, 
.input-group textarea:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 5px rgba(0, 86, 179, 0.2);
}

.error-text {
    display: block;
    color: #f87171;
    font-size: 0.8rem;
    margin-top: 0.3rem;
    min-height: 1rem;
}

.input-group input.invalid,
.input-group textarea.invalid {
    border-color: #f87171;
}

.form-message {
    margin-top: 1rem;
    padding: 0.8rem 1rem;
    border-radius: 8px;
    font-size: 0.9rem;
    display: none;
}

.form-message.success {
    display: block;
    background-color: rgba(34, 197, 94, 0.15);
    color: #4ade80;
    border: 1px solid rgba(74, 222, 128, 0.4);
}

.form-message.error {
    display: block;
    background-color: rgba(248, 113, 113, 0.15);
    color: #f87171;
    border: 1px solid rgba(248, 113, 113, 0.4);
}

/* =========================================
   FOOTER
========================================= */
.site-footer {
    text-align: center;
    padding: 1.5rem 8%;
    background-color: rgba(15, 23, 42, 0.9);
    color: #cbd5e1;
    font-size: 0.9rem;
}

/* =========================================
Untuk HP / Layar Kecil
========================================= */
@media (max-width: 768px) {
    .hero {
        flex-direction: column-reverse;
        text-align: center;
        gap: 2rem;
    }

    .contact-content {
        flex-direction: column;
        text-align: center;
    }

    .cta-buttons {
        justify-content: center;
    }

    .navbar {
        flex-direction: row;
        justify-content: space-between;
        gap: 0;
        position: relative;
    }

    .hamburger {
        display: flex;
    }

    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: rgba(15, 23, 42, 0.97);
        text-align: center;
        padding: 1.5rem 0;
        gap: 1.2rem;
        box-shadow: 0 10px 15px rgba(0, 0, 0, 0.3);
    }

    .nav-links.active {
        display: flex;
    }
}