/* ==========================================================================
   HABIBUR ROHMAN HAYAT — PERSONAL PORTFOLIO
   Clean, Modern, Professional, Student & Developer-Friendly Portfolio
   Architecture: HTML5 + CSS3 + Vanilla JavaScript (No Frameworks, No Backend)
   Default: Dark Mode | Primary Accent: #00ACF5
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. DESIGN TOKENS (CSS VARIABLES)
   -------------------------------------------------------------------------- */
:root {
  /* Dark Mode Palette (Default) */
  --color-bg: #0b0f19;
  --color-bg-alt: #101626;
  --color-surface: #151d30;
  --color-surface-hover: #1c2740;
  --color-surface-elevated: #202c46;
  --color-border: rgba(255, 255, 255, 0.08);
  --color-border-hover: rgba(0, 172, 245, 0.45);

  /* Primary Accent: #00ACF5 */
  --color-primary: #00acf5;
  --color-primary-hover: #0096d6;
  --color-primary-subtle: rgba(0, 172, 245, 0.12);
  --color-primary-border: rgba(0, 172, 245, 0.3);

  /* Typography Colors */
  --color-text-main: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  --color-text-inverse: #0b0f19;

  /* Status Colors */
  --color-success: #10b981;
  --color-success-subtle: rgba(16, 185, 129, 0.12);
  --color-warning: #f59e0b;
  --color-warning-subtle: rgba(245, 158, 11, 0.12);
  --color-error: #ef4444;
  --color-error-subtle: rgba(239, 68, 68, 0.12);

  /* Typography */
  --font-family-base: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --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 */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;

  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 10px 28px rgba(0, 0, 0, 0.45);
  --shadow-primary: 0 4px 18px rgba(0, 172, 245, 0.3);

  /* Layout Constants */
  --container-max: 1140px;
  --header-height: 70px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

/* --------------------------------------------------------------------------
   Light Mode Overrides
   -------------------------------------------------------------------------- */
[data-theme="light"] {
  --color-bg: #f8fafc;
  --color-bg-alt: #f1f5f9;
  --color-surface: #ffffff;
  --color-surface-hover: #f8fafc;
  --color-surface-elevated: #ffffff;
  --color-border: #e2e8f0;
  --color-border-hover: rgba(0, 172, 245, 0.5);

  --color-text-main: #0f172a;
  --color-text-secondary: #475569;
  --color-text-muted: #64748b;
  --color-text-inverse: #ffffff;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 28px rgba(0, 0, 0, 0.12);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 1rem);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  line-height: 1.65;
  color: var(--color-text-main);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

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

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

ul, ol {
  list-style: none;
}

button, input, textarea, select {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

/* Focus Visibility */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
}

/* --------------------------------------------------------------------------
   3. LAYOUT UTILITIES
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.section {
  padding-top: var(--space-16);
  padding-bottom: var(--space-16);
  position: relative;
}

.section-alt {
  background-color: var(--color-bg-alt);
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto var(--space-12);
}

.section-tag {
  display: inline-block;
  font-size: var(--font-size-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-primary);
  margin-bottom: var(--space-2);
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--color-text-main);
  margin-bottom: var(--space-3);
}

.section-subtitle {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   4. BUTTONS
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.75rem 1.4rem;
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 600;
  transition: all var(--transition-fast);
  cursor: pointer;
  white-space: nowrap;
}

.btn svg {
  width: 16px;
  height: 16px;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #0b0f19;
  border: 1px solid var(--color-primary);
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  box-shadow: var(--shadow-primary);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--color-surface);
  color: var(--color-text-main);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover,
.btn-secondary:focus-visible {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background-color: var(--color-surface-hover);
  transform: translateY(-1px);
}

/* --------------------------------------------------------------------------
   5. HEADER & NAVIGATION
   -------------------------------------------------------------------------- */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background-color: rgba(11, 15, 25, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background-color var(--transition-normal);
}

[data-theme="light"] .header {
  background-color: rgba(248, 250, 252, 0.9);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: 800;
  font-size: var(--font-size-lg);
  color: var(--color-text-main);
  letter-spacing: -0.02em;
}

.brand-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-subtle);
  color: var(--color-primary);
  font-size: var(--font-size-sm);
  font-weight: 700;
  border: 1px solid var(--color-primary-border);
}

.brand-text {
  font-weight: 700;
  color: var(--color-text-main);
}

.nav-menu {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  display: inline-block;
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-text-main);
  background-color: var(--color-surface);
}

.nav-link.active {
  color: var(--color-primary);
  background-color: var(--color-primary-subtle);
  font-weight: 600;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.theme-toggle-btn {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  transition: all var(--transition-fast);
}

.theme-toggle-btn:hover {
  color: var(--color-primary);
  border-color: var(--color-border-hover);
}

.theme-toggle-btn .sun-icon {
  width: 18px;
  height: 18px;
  display: none;
}

.theme-toggle-btn .moon-icon {
  width: 18px;
  height: 18px;
  display: block;
}

[data-theme="light"] .theme-toggle-btn .sun-icon {
  display: block;
}

[data-theme="light"] .theme-toggle-btn .moon-icon {
  display: none;
}

.mobile-toggle-btn {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
}

.hamburger-bar {
  width: 18px;
  height: 2px;
  background-color: var(--color-text-main);
  border-radius: 1px;
  transition: all var(--transition-fast);
}

/* --------------------------------------------------------------------------
   6. HERO SECTION
   -------------------------------------------------------------------------- */
.hero-section {
  padding-top: var(--space-16);
  padding-bottom: var(--space-16);
  position: relative;
}

.hero-container {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  align-items: center;
  gap: var(--space-12);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.35rem 0.85rem;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-subtle);
  border: 1px solid var(--color-primary-border);
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-primary);
  box-shadow: 0 0 8px var(--color-primary);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.hero-salutation {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-1);
}

.hero-name {
  font-size: var(--font-size-5xl);
  font-weight: 900;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--color-text-main);
  margin-bottom: var(--space-2);
}

.hero-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

.hero-tagline {
  font-size: var(--font-size-base);
  font-style: italic;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
  padding-left: var(--space-3);
  border-left: 2px solid var(--color-primary);
}

.hero-desc {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.7;
  max-width: 580px;
  margin-bottom: var(--space-8);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.hero-social-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
}

.social-icon-btn {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  font-size: 1rem;
  transition: all var(--transition-fast);
}

.social-icon-btn:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  background-color: var(--color-surface-hover);
}

.hero-visual {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.avatar-frame {
  position: relative;
  width: 270px;
  height: 270px;
  border-radius: 50%;
  padding: 8px;
  background: linear-gradient(145deg, rgba(0, 172, 245, 0.45), rgba(255, 255, 255, 0.05));
  box-shadow: var(--shadow-lg), 0 0 35px rgba(0, 172, 245, 0.15);
}

.avatar-img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  background-color: var(--color-surface);
}

.status-pill {
  margin-top: var(--space-4);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.4rem 0.95rem;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: 500;
  color: var(--color-text-secondary);
}

.status-indicator {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-success);
}

/* --------------------------------------------------------------------------
   7. ABOUT SECTION
   -------------------------------------------------------------------------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: var(--space-12);
  align-items: start;
}

.narrative-block p {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-4);
}

.about-highlights-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  margin-top: var(--space-6);
  margin-bottom: var(--space-6);
}

.about-highlight-card {
  padding: var(--space-4);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
}

.highlight-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-subtle);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
}

.highlight-title {
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-text-main);
  margin-bottom: var(--space-1);
}

.highlight-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.hobbies-container {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  margin-top: var(--space-4);
  margin-bottom: var(--space-6);
}

.about-hobby-card {
  padding: var(--space-5);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.about-hobby-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.hobby-card-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.hobby-icon {
  background-color: rgba(239, 68, 68, 0.12);
  color: #ef4444;
}

.travel-icon {
  background-color: rgba(16, 185, 129, 0.12);
  color: #10b981;
}

.hobby-tag {
  display: inline-block;
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  margin-bottom: 2px;
}

.hobby-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.hobby-channel-link {
  color: var(--color-primary);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--transition-fast);
}

.hobby-channel-link:hover {
  color: var(--color-primary-hover);
}

.about-cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

.about-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.info-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}

.info-card-title {
  font-size: var(--font-size-md);
  font-weight: 700;
  color: var(--color-text-main);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--color-border);
}

.info-card-title svg {
  width: 18px;
  height: 18px;
  color: var(--color-primary);
}

.info-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.info-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--font-size-sm);
}

.info-label {
  color: var(--color-text-muted);
  font-weight: 500;
}

.info-value {
  color: var(--color-text-main);
  font-weight: 600;
  text-align: right;
}

/* --------------------------------------------------------------------------
   8. EDUCATION SECTION & TIMELINE
   -------------------------------------------------------------------------- */
.education-card {
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
}

.education-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--color-border);
  flex-wrap: wrap;
  gap: var(--space-2);
}

.education-card-header .info-card-title {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.timeline {
  position: relative;
  width: 100%;
  margin: 0;
}

.timeline::before {
  content: "";
  position: absolute;
  top: 6px;
  bottom: 6px;
  left: 9px;
  width: 2px;
  background-color: var(--color-border);
}

.timeline-item {
  position: relative;
  padding-left: 32px;
  margin-bottom: var(--space-4);
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-dot {
  position: absolute;
  left: 1px;
  top: 14px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background-color: var(--color-surface);
  border: 3px solid var(--color-primary);
  z-index: 2;
  transition: all var(--transition-fast);
}

.timeline-dot.ongoing-dot {
  border-color: var(--color-warning);
  box-shadow: 0 0 10px rgba(245, 158, 11, 0.45);
}

.timeline-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  transition: all var(--transition-fast);
}

[data-theme="light"] .timeline-card {
  background-color: var(--color-bg-alt);
}

.timeline-card:hover {
  border-color: var(--color-border-hover);
  background-color: var(--color-surface-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.timeline-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-1);
  flex-wrap: wrap;
  gap: var(--space-1);
}

.timeline-year {
  font-size: var(--font-size-xs);
  font-weight: 700;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.timeline-institution {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-text-secondary);
}

.timeline-program {
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-text-main);
  margin-bottom: 2px;
  line-height: 1.4;
}

.timeline-group {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.badge {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.badge-ongoing {
  background-color: var(--color-warning-subtle);
  color: var(--color-warning);
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.badge-completed {
  background-color: var(--color-success-subtle);
  color: var(--color-success);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.timeline-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: 1.55;
  margin: 0;
}

.info-competencies-link {
  color: var(--color-primary);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--transition-fast);
}

.info-competencies-link:hover {
  color: var(--color-primary-hover);
}

/* --------------------------------------------------------------------------
   9. CORE COMPETENCIES SECTION
   -------------------------------------------------------------------------- */
.competencies-filter-bar {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-8);
}

.filter-tab {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.55rem 1.15rem;
  border-radius: var(--radius-full);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  font-size: var(--font-size-xs);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
}

.filter-tab:hover {
  color: var(--color-text-main);
  border-color: var(--color-primary-border);
  background-color: var(--color-surface-hover);
  transform: translateY(-1px);
}

.filter-tab.active {
  background-color: var(--color-primary);
  color: #0b0f19;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-primary);
  font-weight: 700;
}

.filter-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  padding: 0.1rem 0.45rem;
  border-radius: var(--radius-full);
  background-color: rgba(255, 255, 255, 0.12);
  color: inherit;
  font-weight: 700;
}

.filter-tab.active .filter-count {
  background-color: rgba(0, 0, 0, 0.2);
  color: #0b0f19;
}

.competencies-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
  margin-bottom: var(--space-10);
}

.competency-card {
  position: relative;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal), background-color var(--transition-normal);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.competency-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--card-accent, var(--color-primary)), transparent);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.competency-card:hover {
  transform: translateY(-4px);
  border-color: var(--card-accent-border, var(--color-primary-border));
  box-shadow: var(--shadow-md), 0 0 22px var(--card-accent-glow, rgba(0, 172, 245, 0.18));
  background-color: var(--color-surface-hover);
}

.competency-card:hover::before {
  opacity: 1;
}

.competency-card.hidden {
  display: none !important;
}

.competency-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.competency-icon-box {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  flex-shrink: 0;
  transition: transform var(--transition-fast);
  background-color: var(--card-icon-bg, var(--color-primary-subtle));
  color: var(--card-accent, var(--color-primary));
  border: 1px solid var(--card-icon-border, var(--color-primary-border));
}

.competency-card:hover .competency-icon-box {
  transform: scale(1.08) rotate(3deg);
}

.competency-badge {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-full);
  background-color: var(--color-bg);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
}

[data-theme="light"] .competency-badge {
  background-color: var(--color-bg-alt);
}

.competency-title {
  font-size: var(--font-size-lg);
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--color-text-main);
  margin-bottom: var(--space-2);
}

.competency-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: var(--space-5);
  flex-grow: 1;
}

.competency-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-top: auto;
}

.tech-chip {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.2rem 0.55rem;
  border-radius: var(--radius-sm);
  background-color: var(--color-bg);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  transition: all var(--transition-fast);
}

[data-theme="light"] .tech-chip {
  background-color: var(--color-bg-alt);
}

.competency-card:hover .tech-chip {
  color: var(--color-text-secondary);
  border-color: rgba(255, 255, 255, 0.16);
}

[data-theme="light"] .competency-card:hover .tech-chip {
  border-color: rgba(0, 0, 0, 0.14);
}

/* Card Individual Brand Theming */
.card-python {
  --card-accent: #3776ab;
  --card-icon-bg: rgba(55, 118, 171, 0.15);
  --card-icon-border: rgba(55, 118, 171, 0.35);
  --card-accent-border: rgba(55, 118, 171, 0.5);
  --card-accent-glow: rgba(55, 118, 171, 0.2);
}

.card-webdev {
  --card-accent: #00acf5;
  --card-icon-bg: rgba(0, 172, 245, 0.15);
  --card-icon-border: rgba(0, 172, 245, 0.35);
  --card-accent-border: rgba(0, 172, 245, 0.5);
  --card-accent-glow: rgba(0, 172, 245, 0.2);
}

.card-fastapi {
  --card-accent: #059669;
  --card-icon-bg: rgba(5, 150, 105, 0.15);
  --card-icon-border: rgba(5, 150, 105, 0.35);
  --card-accent-border: rgba(5, 150, 105, 0.5);
  --card-accent-glow: rgba(5, 150, 105, 0.2);
}

.card-aiauto {
  --card-accent: #a855f7;
  --card-icon-bg: rgba(168, 85, 247, 0.15);
  --card-icon-border: rgba(168, 85, 247, 0.35);
  --card-accent-border: rgba(168, 85, 247, 0.5);
  --card-accent-glow: rgba(168, 85, 247, 0.2);
}

.card-linux {
  --card-accent: #f59e0b;
  --card-icon-bg: rgba(245, 158, 11, 0.15);
  --card-icon-border: rgba(245, 158, 11, 0.35);
  --card-accent-border: rgba(245, 158, 11, 0.5);
  --card-accent-glow: rgba(245, 158, 11, 0.2);
}

.card-networking {
  --card-accent: #3b82f6;
  --card-icon-bg: rgba(59, 130, 246, 0.15);
  --card-icon-border: rgba(59, 130, 246, 0.35);
  --card-accent-border: rgba(59, 130, 246, 0.5);
  --card-accent-glow: rgba(59, 130, 246, 0.2);
}

.card-windows {
  --card-accent: #0284c7;
  --card-icon-bg: rgba(2, 132, 199, 0.15);
  --card-icon-border: rgba(2, 132, 199, 0.35);
  --card-accent-border: rgba(2, 132, 199, 0.5);
  --card-accent-glow: rgba(2, 132, 199, 0.2);
}

.card-html {
  --card-accent: #e34f26;
  --card-icon-bg: rgba(227, 79, 38, 0.15);
  --card-icon-border: rgba(227, 79, 38, 0.35);
  --card-accent-border: rgba(227, 79, 38, 0.5);
  --card-accent-glow: rgba(227, 79, 38, 0.2);
}

.card-css {
  --card-accent: #2563eb;
  --card-icon-bg: rgba(37, 99, 235, 0.15);
  --card-icon-border: rgba(37, 99, 235, 0.35);
  --card-accent-border: rgba(37, 99, 235, 0.5);
  --card-accent-glow: rgba(37, 99, 235, 0.2);
}

.card-javascript {
  --card-accent: #eab308;
  --card-icon-bg: rgba(234, 179, 8, 0.15);
  --card-icon-border: rgba(234, 179, 8, 0.35);
  --card-accent-border: rgba(234, 179, 8, 0.5);
  --card-accent-glow: rgba(234, 179, 8, 0.2);
}

/* Competencies Architecture Strip */
.competencies-summary-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.summary-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-primary);
}

.summary-pillars-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}

.pillar-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

[data-theme="light"] .pillar-item {
  background-color: var(--color-bg-alt);
}

.pillar-item:hover {
  border-color: var(--color-primary-border);
  transform: translateY(-2px);
}

.pillar-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-subtle);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.05rem;
  flex-shrink: 0;
}

.pillar-title {
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-text-main);
  margin-bottom: 2px;
}

.pillar-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: 1.4;
}

/* --------------------------------------------------------------------------
   10. CONTACT SECTION
   -------------------------------------------------------------------------- */
.contact-channels-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
  max-width: 860px;
  margin: 0 auto;
}

.contact-channel-card {
  padding: var(--space-6);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  gap: var(--space-4);
  transition: all var(--transition-fast);
  position: relative;
  box-shadow: var(--shadow-sm);
}

.contact-channel-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  background-color: var(--color-surface-hover);
}

.channel-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background-color: var(--color-primary-subtle);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  flex-shrink: 0;
}

.whatsapp-icon {
  background-color: rgba(37, 211, 102, 0.12);
  color: #25d366;
}

.phone-icon {
  background-color: rgba(59, 130, 246, 0.12);
  color: #3b82f6;
}

.location-icon {
  background-color: rgba(245, 158, 11, 0.12);
  color: #f59e0b;
}

.channel-info {
  flex: 1;
  min-width: 0;
}

.channel-label {
  display: block;
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  font-weight: 500;
  margin-bottom: 2px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.channel-value {
  display: block;
  font-size: var(--font-size-base);
  font-weight: 700;
  color: var(--color-text-main);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.channel-action-badge {
  font-size: var(--font-size-xs);
  font-weight: 600;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-subtle);
  color: var(--color-primary);
  border: 1px solid var(--color-primary-border);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.contact-channel-card:hover .channel-action-badge {
  background-color: var(--color-primary);
  color: #0b0f19;
}

.location-badge {
  background-color: rgba(245, 158, 11, 0.12);
  color: var(--color-warning);
  border-color: rgba(245, 158, 11, 0.3);
}

.location-channel-card:hover .location-badge {
  background-color: var(--color-warning);
  color: #0b0f19;
}

/* --------------------------------------------------------------------------
   10. FOOTER
   -------------------------------------------------------------------------- */
.footer {
  margin-top: auto;
  background-color: var(--color-bg);
  border-top: 1px solid var(--color-border);
  padding: var(--space-12) 0 var(--space-8);
}

.footer-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-6);
  padding-bottom: var(--space-8);
  border-bottom: 1px solid var(--color-border);
}

.footer-brand {
  max-width: 360px;
}

.footer-brand-title {
  font-size: var(--font-size-base);
  font-weight: 700;
  color: var(--color-text-main);
  margin-top: var(--space-2);
}

.footer-brand-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
}

.footer-socials {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.footer-social-pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  font-size: var(--font-size-xs);
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.footer-social-pill:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: var(--color-surface-hover);
  transform: translateY(-1px);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
  padding-top: var(--space-6);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.footer-nav {
  display: flex;
  gap: var(--space-4);
}

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

/* --------------------------------------------------------------------------
   11. SCROLL TO TOP BUTTON
   -------------------------------------------------------------------------- */
.scroll-top-btn {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-fast);
  z-index: 90;
  box-shadow: var(--shadow-md);
}

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

.scroll-top-btn:hover {
  background-color: var(--color-primary);
  color: #0b0f19;
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.scroll-top-btn svg {
  width: 20px;
  height: 20px;
}

/* --------------------------------------------------------------------------
   12. RESPONSIVE DESIGN BREAKPOINTS
   -------------------------------------------------------------------------- */
@media (max-width: 992px) {
  .hero-container {
    display: flex;
    flex-direction: column;
    text-align: center;
    gap: var(--space-6);
  }

  .hero-visual {
    order: -1;
    margin-bottom: var(--space-2);
  }

  .avatar-frame {
    width: 210px;
    height: 210px;
  }

  .hero-desc {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-social-bar {
    justify-content: center;
  }

  .hero-tagline {
    border-left: none;
    border-bottom: 2px solid var(--color-primary);
    padding-left: 0;
    padding-bottom: var(--space-2);
    display: inline-block;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .competencies-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
  }
}

@media (max-width: 768px) {
  .section {
    padding-top: 3rem;
    padding-bottom: 3rem;
  }

  .summary-pillars-grid {
    grid-template-columns: 1fr;
  }

  .hero-section {
    padding-top: 2.75rem;
    padding-bottom: 2.75rem;
  }

  .section-header {
    margin-bottom: 2rem;
  }

  .section-title {
    font-size: 1.65rem;
  }

  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-5);
    display: none;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
  }

  .nav-menu.open {
    display: flex;
  }

  .nav-list {
    flex-direction: column;
    width: 100%;
    gap: var(--space-2);
  }

  .nav-link {
    width: 100%;
    padding: 0.75rem 1rem;
  }

  .mobile-toggle-btn {
    display: flex;
  }

  .hero-name {
    font-size: 2.1rem;
  }

  .about-highlights-grid {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  .timeline::before {
    left: 9px;
  }

  .timeline-item {
    padding-left: 30px;
  }

  .timeline-dot {
    left: 1px;
  }
}

@media (max-width: 640px) {
  .contact-channels-grid {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 480px) {
  .section {
    padding-top: 2.25rem;
    padding-bottom: 2.25rem;
  }

  .hero-section {
    padding-top: 1.75rem;
    padding-bottom: 2rem;
  }

  .section-header {
    margin-bottom: 1.5rem;
  }

  .section-tag {
    font-size: 0.7rem;
    letter-spacing: 0.08em;
  }

  .section-title {
    font-size: 1.45rem;
    margin-bottom: var(--space-2);
  }

  .section-subtitle {
    font-size: 0.875rem;
    line-height: 1.5;
  }

  .avatar-frame {
    width: 155px;
    height: 155px;
    padding: 6px;
  }

  .status-pill {
    margin-top: var(--space-3);
    padding: 0.3rem 0.75rem;
    font-size: 0.75rem;
  }

  .hero-badge {
    font-size: 0.75rem;
    padding: 0.25rem 0.75rem;
    margin-bottom: var(--space-3);
  }

  .hero-salutation {
    font-size: 1rem;
  }

  .hero-name {
    font-size: 1.65rem;
    margin-bottom: var(--space-2);
  }

  .hero-title {
    font-size: 1.05rem;
    margin-bottom: var(--space-3);
  }

  .hero-tagline {
    font-size: 0.875rem;
    margin-bottom: var(--space-3);
    padding-bottom: var(--space-1);
  }

  .hero-desc {
    font-size: 0.875rem;
    line-height: 1.55;
    margin-bottom: var(--space-6);
  }

  .btn {
    width: 100%;
    padding: 0.65rem 1.25rem;
    font-size: 0.85rem;
  }

  .hero-actions {
    flex-direction: column;
    gap: 0.6rem;
    margin-bottom: var(--space-6);
  }

  .hero-social-bar {
    gap: 0.5rem;
  }

  .social-icon-btn {
    width: 36px;
    height: 36px;
    font-size: 0.9rem;
  }

  .about-hobby-card,
  .info-card,
  .project-card-content,
  .contact-channel-card,
  .timeline-card,
  .competency-card,
  .competencies-summary-card {
    padding: 1.05rem;
  }

  .project-title {
    font-size: 1.15rem;
  }

  .project-desc {
    font-size: 0.85rem;
  }

  .competency-title {
    font-size: 1.05rem;
  }

  .skill-category-title {
    font-size: 1.05rem;
  }

  .skill-tag,
  .tech-chip {
    padding: 0.35rem 0.65rem;
    font-size: 0.72rem;
  }

  .timeline-title {
    font-size: 1.05rem;
  }

  .timeline-org {
    font-size: 0.85rem;
  }

  .channel-icon {
    width: 42px;
    height: 42px;
    font-size: 1.15rem;
  }

  .channel-label {
    font-size: 0.75rem;
  }

  .channel-value {
    font-size: 0.9rem;
  }

  .footer-top {
    flex-direction: column;
    text-align: center;
    align-items: center;
    gap: var(--space-4);
  }

  .footer-socials {
    justify-content: center;
  }

  .footer-nav {
    justify-content: center;
    gap: var(--space-4);
    font-size: 0.85rem;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
    font-size: 0.8rem;
    gap: var(--space-2);
  }
}

@media (max-width: 375px) {
  .avatar-frame {
    width: 135px;
    height: 135px;
    padding: 5px;
  }

  .hero-name {
    font-size: 1.45rem;
  }

  .section-title {
    font-size: 1.3rem;
  }

  .hero-desc {
    font-size: 0.825rem;
  }

  .btn {
    padding: 0.6rem 1rem;
    font-size: 0.825rem;
  }

  .contact-channel-card {
    padding: 0.85rem;
  }

  .channel-icon {
    width: 38px;
    height: 38px;
    font-size: 1rem;
  }

  .social-icon-btn {
    width: 34px;
    height: 34px;
    font-size: 0.85rem;
  }
}

/* --------------------------------------------------------------------------
   13. ACCESSIBILITY: REDUCED MOTION SUPPORT
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}