/* ===== CSS VARIABLES ===== */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f4f6f9;
    --bg-tertiary: #e8ecf0;
    --text-primary: #0d1117;
    --text-secondary: #57606a;
    --accent-primary: #0969da;
    --accent-secondary: #0550ae;
    --accent-light: #ddf4ff;
    --accent-glow: rgba(9, 105, 218, 0.15);
    --border-color: #d0d7de;
    --shadow: rgba(31, 35, 40, 0.1);
    --shadow-lg: rgba(31, 35, 40, 0.2);
    --success-bg: #dafbe1;
    --success-text: #1a7f37;
    --success-border: #aceebb;
    --error-bg: #ffebe9;
    --error-text: #cf222e;
    --error-border: #ffcecb;

    --font-primary: 'Sora', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'Space Mono', monospace;

    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    --radius-sm: 0.375rem;
    --radius-md: 0.625rem;
    --radius-lg: 1.25rem;
    --radius-full: 9999px;

    --transition-base: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.45s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --accent-primary: #388bfd;
    --accent-secondary: #58a6ff;
    --accent-light: #112d45;
    --accent-glow: rgba(56, 139, 253, 0.2);
    --border-color: #30363d;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-lg: rgba(0, 0, 0, 0.5);
    --success-bg: #0d2817;
    --success-text: #56d364;
    --success-border: #1a7f37;
    --error-bg: #2d1117;
    --error-text: #ff7b72;
    --error-border: #cf222e;
}

/* ===== RESET & BASE ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html { scroll-behavior: smooth; }

body {
    font-family: var(--font-primary);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    transition: background-color 0.35s ease, color 0.35s ease;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

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

/* ===== NAVIGATION ===== */
.navbar {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition-base);
}

[data-theme="dark"] .navbar {
    background-color: rgba(13, 17, 23, 0.88);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem var(--spacing-md);
}

.nav-brand {
    font-family: var(--font-mono);
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.nav-brand .accent {
    color: var(--accent-primary);
    font-size: 1.6rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0.25rem;
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    padding: 0.4rem 0.75rem;
    border-radius: var(--radius-sm);
    transition: var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-primary);
    background-color: var(--accent-light);
}

.theme-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    padding: 0.4rem 0.75rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 1rem;
    transition: var(--transition-base);
    color: var(--text-primary);
}

.theme-btn:hover {
    transform: scale(1.1);
    border-color: var(--accent-primary);
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.hamburger span {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition-base);
    display: block;
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.7rem 1.5rem;
    border-radius: var(--radius-md);
    font-family: var(--font-primary);
    font-weight: 600;
    font-size: 0.95rem;
    transition: var(--transition-base);
    border: none;
    cursor: pointer;
    letter-spacing: 0.01em;
}

.btn-primary {
    background-color: var(--accent-primary);
    color: white;
    box-shadow: 0 1px 3px var(--shadow);
}

.btn-primary:hover {
    background-color: var(--accent-secondary);
    transform: translateY(-2px);
    box-shadow: 0 6px 18px var(--accent-glow);
}

.btn-secondary {
    background-color: transparent;
    color: var(--accent-primary);
    border: 1.5px solid var(--accent-primary);
}

.btn-secondary:hover {
    background-color: var(--accent-light);
}

/* ===== DIFFICULTY SELECTOR ===== */
.difficulty-wrapper {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.difficulty-wrapper label {
    font-weight: 600;
    color: var(--text-primary);
    white-space: nowrap;
    font-size: 0.95rem;
}

.difficulty-select {
    padding: var(--spacing-xs) var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-primary);
    cursor: pointer;
    transition: var(--transition-base);
    font-size: 0.95rem;
}

.difficulty-select:hover {
    border-color: var(--accent-primary);
}

.difficulty-select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

/* ===== HERO SECTION ===== */
.hero {
    padding: var(--spacing-xl) 0;
    position: relative;
    overflow: hidden;
    background: linear-gradient(160deg, var(--bg-secondary) 0%, var(--bg-primary) 60%);
}

.hero-bg-grid {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(var(--border-color) 1px, transparent 1px),
        linear-gradient(90deg, var(--border-color) 1px, transparent 1px);
    background-size: 40px 40px;
    opacity: 0.4;
    pointer-events: none;
    mask-image: radial-gradient(ellipse 70% 70% at 50% 50%, black 40%, transparent 100%);
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.greeting {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.9rem;
    color: var(--accent-primary);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    background: var(--accent-light);
    border: 1px solid var(--accent-primary);
    padding: 0.3rem 1rem;
    border-radius: var(--radius-full);
    letter-spacing: 0.05em;
    animation: fadeInDown 0.6s ease both;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--text-primary) 30%, var(--accent-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: fadeInUp 0.7s ease 0.1s both;
}

.hero-tagline {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    font-weight: 400;
    min-height: 1.9rem;
    animation: fadeInUp 0.7s ease 0.2s both;
}

.hero-tagline .cursor {
    display: inline-block;
    width: 2px;
    height: 1.2em;
    background: var(--accent-primary);
    margin-left: 2px;
    vertical-align: middle;
    animation: blink 1s step-end infinite;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
    max-width: 680px;
    margin-left: auto;
    margin-right: auto;
    animation: fadeInUp 0.7s ease 0.3s both;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.7s ease 0.4s both;
}

/* ===== SECTIONS ===== */
.section { padding: var(--spacing-xl) 0; }

.section:nth-child(even) { background-color: var(--bg-secondary); }

.section-title {
    font-size: clamp(1.8rem, 4vw, 2.75rem);
    font-weight: 800;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    letter-spacing: -0.02em;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -0.75rem;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    border-radius: 2px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-top: -2.5rem;
    margin-bottom: 2.5rem;
    font-size: 1rem;
}

/* ===== ABOUT ===== */
.about-content {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: var(--spacing-lg);
    align-items: start;
}

.profile-image {
    width: 220px;
    height: 220px;
    border-radius: 50%;
    object-fit: cover;
    object-position: center top;
    display: block;
    margin: 0 auto;
    border: 3px solid var(--border-color);
    box-shadow: 0 8px 32px var(--shadow);
    transition: var(--transition-base);
}

.profile-image:hover {
    transform: scale(1.04);
    box-shadow: 0 14px 40px var(--shadow-lg);
    border-color: var(--accent-primary);
}

.about-text p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
    font-size: 1.05rem;
}

/* ===== ACCORDION ===== */
.accordion {
    margin-top: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.accordion-item {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition-base);
}

.accordion-item:hover {
    border-color: var(--accent-primary);
}

.accordion-header {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.9rem 1.25rem;
    background: var(--bg-primary);
    border: none;
    cursor: pointer;
    font-family: var(--font-primary);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    text-align: left;
    transition: var(--transition-base);
}

.accordion-header:hover {
    background: var(--accent-light);
    color: var(--accent-primary);
}

.accordion-header[aria-expanded="true"] {
    background: var(--accent-light);
    color: var(--accent-primary);
}

.accordion-icon {
    font-size: 1.3rem;
    font-weight: 300;
    transition: transform 0.3s ease;
    flex-shrink: 0;
}

.accordion-header[aria-expanded="true"] .accordion-icon {
    transform: rotate(45deg);
}

.accordion-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), padding 0.3s ease;
    padding: 0 1.25rem;
    background: var(--bg-secondary);
}

.accordion-body.open {
    max-height: 200px;
    padding: 1rem 1.25rem;
}

.accordion-body p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* ===== SKILLS ===== */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--spacing-md);
}

.skill-category {
    background-color: var(--bg-primary);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 8px var(--shadow);
    transition: var(--transition-base);
}

.skill-category:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 28px var(--shadow-lg);
    border-color: var(--accent-primary);
}

.skill-category h3 {
    font-size: 1rem;
    font-family: var(--font-mono);
    margin-bottom: var(--spacing-sm);
    color: var(--accent-primary);
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

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

.skill-tag {
    background-color: var(--accent-light);
    color: var(--accent-primary);
    padding: 0.35rem 0.85rem;
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 600;
    border: 1px solid transparent;
    transition: var(--transition-base);
}

.skill-tag:hover {
    border-color: var(--accent-primary);
    transform: scale(1.05);
}

/* ===== PROJECTS ===== */

/* Filter & Search Controls */
.projects-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
}

.search-wrapper {
    position: relative;
    flex: 1;
    min-width: 220px;
    max-width: 380px;
}

.search-icon {
    position: absolute;
    left: 0.85rem;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    color: var(--text-secondary);
    pointer-events: none;
}

.search-input {
    width: 100%;
    padding: 0.65rem 2.5rem 0.65rem 2.75rem;
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    transition: var(--transition-base);
}

.search-input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.search-input::placeholder { color: var(--text-secondary); }

.search-clear {
    position: absolute;
    right: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 0.9rem;
    padding: 2px;
    transition: var(--transition-base);
}

.search-clear:hover { color: var(--error-text); }

.filter-tabs {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.filter-tab {
    background: var(--bg-primary);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-full);
    padding: 0.4rem 1rem;
    font-family: var(--font-primary);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition-base);
}

.filter-tab:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: var(--accent-light);
}

.filter-tab.active {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
}

.sort-wrapper {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.sort-wrapper label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.sort-select {
    padding: 0.4rem 0.75rem;
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.85rem;
    cursor: pointer;
    font-family: var(--font-primary);
    transition: var(--transition-base);
}

.sort-select:hover {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.sort-select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

/* Projects Grid */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.project-card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 8px var(--shadow);
    transition: var(--transition-slow);
    opacity: 1;
    transform: scale(1);
}

.project-card:hover {
    transform: translateY(-8px) scale(1.01);
    box-shadow: 0 16px 40px var(--shadow-lg);
    border-color: var(--accent-primary);
}

.project-card.hidden {
    display: none;
}

.project-card.fade-out {
    opacity: 0;
    transform: scale(0.95);
    pointer-events: none;
}

.project-image {
    width: 100%;
    height: 200px;
    overflow: hidden;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-tertiary);
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    display: block;
    transition: transform 0.45s ease;
}

.project-card:hover .project-image img {
    transform: scale(1.07);
}

.project-content { padding: 1.5rem; }

.project-content h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 0.6rem;
    letter-spacing: -0.01em;
}

.project-content p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.project-tech { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.tech-tag {
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 0.2rem 0.65rem;
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 600;
    border: 1px solid var(--border-color);
}

/* No results state */
.no-results {
    text-align: center;
    padding: var(--spacing-lg);
    color: var(--text-secondary);
    animation: fadeInUp 0.3s ease both;
}

.no-results-icon { font-size: 3rem; margin-bottom: 1rem; }
.no-results h3 { font-size: 1.4rem; margin-bottom: 0.5rem; color: var(--text-primary); }
.no-results p { margin-bottom: 1.5rem; }

/* ===== EXPERIENCE / TIMELINE ===== */
.timeline {
    max-width: 780px;
    margin: 0 auto;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 18px;
    top: 10px;
    bottom: 10px;
    width: 2px;
    background: linear-gradient(180deg, var(--accent-primary), transparent);
}

.timeline-item {
    position: relative;
    padding-left: 55px;
    margin-bottom: var(--spacing-md);
}

.timeline-dot {
    position: absolute;
    left: 9px;
    top: 4px;
    width: 18px;
    height: 18px;
    background: var(--accent-primary);
    border: 3px solid var(--bg-primary);
    border-radius: 50%;
    box-shadow: 0 0 0 3px var(--accent-light);
    transition: var(--transition-base);
}

.timeline-item:hover .timeline-dot {
    transform: scale(1.3);
    box-shadow: 0 0 0 5px var(--accent-glow);
}

.timeline-content {
    background: var(--bg-primary);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 8px var(--shadow);
    transition: var(--transition-base);
}

.timeline-item:hover .timeline-content {
    border-color: var(--accent-primary);
    box-shadow: 0 6px 20px var(--shadow-lg);
}

.timeline-content h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 0.3rem;
    color: var(--accent-primary);
}

.timeline-role {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.6rem;
    font-family: var(--font-mono);
}

.timeline-content p { color: var(--text-secondary); font-size: 0.95rem; }

/* ===== FACTS SECTION ===== */
.facts { background-color: var(--bg-secondary); }

.fact-card {
    max-width: 680px;
    margin: 0 auto;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: 0 4px 16px var(--shadow);
    text-align: center;
    transition: var(--transition-base);
}

.fact-loader, .fact-content, .fact-error {
    margin-bottom: 1.5rem;
}

.spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--border-color);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 1rem;
}

.fact-icon { font-size: 2.5rem; margin-bottom: 0.75rem; }

blockquote {
    font-size: 1.1rem;
    font-style: italic;
    color: var(--text-primary);
    line-height: 1.8;
    border-left: 3px solid var(--accent-primary);
    padding-left: 1.25rem;
    text-align: left;
    margin: 0 0 1rem;
}

.fact-source {
    font-size: 0.85rem;
    font-family: var(--font-mono);
    color: var(--text-secondary);
}

.fact-btn { margin: 0 auto; }

/* ===== CONTACT ===== */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.6fr;
    gap: var(--spacing-lg);
}

.contact-info h3 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--accent-primary);
}

.contact-info > p {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

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

.contact-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.contact-item svg {
    width: 20px;
    height: 20px;
    color: var(--accent-primary);
    flex-shrink: 0;
}

.contact-item a {
    color: var(--accent-primary);
    font-weight: 500;
}

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

/* ===== FORM ===== */
.contact-form {
    background: var(--bg-primary);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 16px var(--shadow);
}

.form-group { margin-bottom: 1.25rem; }

.form-group label {
    display: block;
    margin-bottom: 0.4rem;
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.7rem 1rem;
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 0.95rem;
    transition: var(--transition-base);
    resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
    background: var(--bg-primary);
}

.form-group input.invalid,
.form-group textarea.invalid {
    border-color: var(--error-text);
    box-shadow: 0 0 0 3px rgba(207, 34, 46, 0.12);
}

.field-error {
    display: block;
    font-size: 0.8rem;
    color: var(--error-text);
    margin-top: 0.3rem;
    min-height: 1.1rem;
    font-weight: 500;
}

.form-message {
    margin-top: 1rem;
    padding: 0.85rem 1rem;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 500;
    display: none;
    animation: fadeInUp 0.3s ease;
}

.form-message.success {
    display: block;
    background: var(--success-bg);
    color: var(--success-text);
    border: 1px solid var(--success-border);
}

.form-message.error {
    display: block;
    background: var(--error-bg);
    color: var(--error-text);
    border: 1px solid var(--error-border);
}

/* ===== FOOTER ===== */
.footer {
    background: var(--bg-secondary);
    padding: var(--spacing-md) 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: 0.2rem 0;
}

/* ===== SCROLL TO TOP ===== */
.scroll-top-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    background: var(--accent-primary);
    color: white;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-base);
    z-index: 999;
    box-shadow: 0 4px 14px var(--accent-glow);
    display: flex;
    align-items: center;
    justify-content: center;
}

.scroll-top-btn.visible {
    opacity: 1;
    visibility: visible;
}

.scroll-top-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px var(--accent-glow);
}

/* ===== ANIMATIONS ===== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(24px); }
    to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-16px); }
    to   { opacity: 1; transform: translateY(0); }
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

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

/* Scroll-reveal class */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger children */
.reveal-children > * {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal-children.visible > *:nth-child(1) { opacity: 1; transform: none; transition-delay: 0s; }
.reveal-children.visible > *:nth-child(2) { opacity: 1; transform: none; transition-delay: 0.1s; }
.reveal-children.visible > *:nth-child(3) { opacity: 1; transform: none; transition-delay: 0.2s; }
.reveal-children.visible > *:nth-child(4) { opacity: 1; transform: none; transition-delay: 0.3s; }

/* ===== ASSIGNMENT 3: SECTION HEADER & TOGGLES ===== */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.section-header .section-title {
    margin-bottom: 0;
}

.section-toggle {
    padding: 0.5rem 1.25rem;
    background: var(--accent-primary);
    color: #fff;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    transition: var(--transition-base);
    white-space: nowrap;
}

.section-toggle:hover {
    background: var(--accent-secondary);
    transform: translateY(-2px);
}

.section-toggle:active {
    transform: translateY(0);
}

/* ===== ASSIGNMENT 3: GITHUB REPOSITORIES SECTION ===== */
#github {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

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

.sort-wrapper,
.filter-wrapper {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.sort-wrapper label,
.filter-wrapper label {
    font-weight: 600;
    color: var(--text-primary);
}

.sort-select,
.language-select {
    padding: 0.5rem var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.95rem;
    cursor: pointer;
    transition: var(--transition-base);
}

.sort-select:hover,
.language-select:hover {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.sort-select:focus,
.language-select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.repos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(330px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.repo-loader {
    grid-column: 1 / -1;
    text-align: center;
    padding: var(--spacing-lg);
}

.repo-card {
    padding: var(--spacing-md);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: var(--transition-base);
    display: flex;
    flex-direction: column;
}

.repo-card:hover {
    border-color: var(--accent-primary);
    box-shadow: 0 8px 24px var(--shadow-lg);
    transform: translateY(-4px);
}

.repo-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.repo-name {
    margin: 0;
    font-size: 1.1rem;
    font-weight: 700;
}

.repo-name a {
    color: var(--accent-primary);
    transition: var(--transition-base);
}

.repo-name a:hover {
    color: var(--accent-secondary);
}

.repo-fork {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: var(--accent-glow);
    color: var(--accent-primary);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    white-space: nowrap;
}

.repo-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin: 0 0 var(--spacing-sm) 0;
    flex-grow: 1;
    line-height: 1.5;
}

.repo-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    font-size: 0.85rem;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
    padding-top: var(--spacing-sm);
}

.repo-language {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: var(--accent-primary);
    color: #fff;
    border-radius: var(--radius-full);
    font-weight: 600;
}

.repo-stars,
.repo-date {
    display: flex;
    align-items: center;
}

.repos-error,
.repos-empty {
    grid-column: 1 / -1;
    text-align: center;
    padding: var(--spacing-lg);
    color: var(--text-secondary);
}

.repos-error p {
    margin-bottom: var(--spacing-md);
}

/* ===== SECTION VISIBILITY STATES ===== */
.section-content {
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 968px) {
    .nav-menu {
        position: fixed;
        top: 60px;
        left: -100%;
        width: 100%;
        flex-direction: column;
        background: var(--bg-primary);
        padding: 1.5rem;
        box-shadow: 0 10px 30px var(--shadow);
        transition: left 0.3s ease;
        border-bottom: 1px solid var(--border-color);
        gap: 0.5rem;
    }

    .nav-menu.active { left: 0; }
    .hamburger { display: flex; }

    .hamburger.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
    .hamburger.active span:nth-child(2) { opacity: 0; }
    .hamburger.active span:nth-child(3) { transform: rotate(-45deg) translate(7px, -6px); }

    .about-content { grid-template-columns: 1fr; text-align: center; }
    .contact-content { grid-template-columns: 1fr; }

    .timeline::before { left: 10px; }
    .timeline-item { padding-left: 42px; }
    .timeline-dot { left: 1px; }

    .projects-controls { flex-direction: column; align-items: stretch; }
    .search-wrapper { max-width: 100%; }
    .filter-tabs { justify-content: center; }
}

@media (max-width: 640px) {
    .hero { padding: var(--spacing-lg) 0; }
    .section { padding: var(--spacing-lg) 0; }
    .hero-cta { flex-direction: column; }
    .btn { width: 100%; justify-content: center; }
    .skills-grid { grid-template-columns: 1fr; }
    .projects-grid { grid-template-columns: 1fr; }
    .about-content { gap: var(--spacing-md); }
}