/*
  ============================================================================
  PORTFOLIO STYLESHEET
  ============================================================================
  Oliver Ibrahim — Portfolio Website Styles
  - Modern, minimal, responsive design
  - Primary accent color: #007bff (blue)
  - Uses CSS custom properties (variables) for easy theming
  - Mobile-first responsive approach
  ============================================================================
*/

/* ============================================================================
   CSS CUSTOM PROPERTIES (VARIABLES)
   ============================================================================
   Centralized color scheme and design tokens for consistent styling
   ============================================================================ */
:root {
  --bg: #ffffff;                    /* Main background color (white) */
  --text: #0b0f14;                  /* Primary text color (dark gray) */
  --muted: #5b6470;                 /* Secondary/muted text color (medium gray) */
  --accent: #007bff;                /* Primary accent color (blue) */
  --border: #e7ecf2;                /* Border color (light gray) */
  --card: #f9fbfd;                 /* Card background color (very light gray) */
  --shadow: 0 10px 30px rgba(11, 15, 20, 0.06);  /* Default box shadow */
  --radius: 14px;                   /* Default border radius for cards */
  --radius-sm: 10px;                /* Small border radius for buttons/inputs */
}

/* ============================================================================
   RESET & BASE STYLES
   ============================================================================ */

/* Box-sizing reset - ensures padding and border are included in element width */
* {
  box-sizing: border-box;
}

/* Smooth scrolling for anchor links and scroll padding for fixed header */
html {
  scroll-behavior: smooth;          /* Smooth scroll animation */
  scroll-padding-top: 80px;         /* Offset for fixed header when scrolling to anchors */
}

/* Base body styles - typography, colors, and layout */
body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, 'Apple Color Emoji', 'Segoe UI Emoji';
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;                 /* Improved readability */
  scroll-behavior: smooth;
}

/* Image and SVG alignment */
img, svg {
  display: inline-block;
  vertical-align: middle;
}

/* Link default styling - inherits text color, no underline */
a {
  color: inherit;
  text-decoration: none;
}

/* ============================================================================
   LAYOUT UTILITIES
   ============================================================================ */

/* Container - centers content with max-width and responsive padding */
.container {
  width: min(1100px, 92%);          /* Max width 1100px, 92% on smaller screens */
  margin: 0 auto;                   /* Center horizontally */
}

/* ============================================================================
   ACCESSIBILITY - SKIP LINK
   ============================================================================
   Hidden by default, visible on focus for keyboard navigation users
   ============================================================================ */
.skip-link {
  position: absolute;
  left: -9999px;                    /* Move off-screen */
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

/* Show skip link when focused (keyboard navigation) */
.skip-link:focus {
  position: fixed;
  left: 16px;
  top: 16px;
  width: auto;
  height: auto;
  padding: 10px 14px;
  background: var(--text);
  color: #fff;
  z-index: 1000;                    /* Above all other content */
  border-radius: 8px;
}

/* ============================================================================
   HEADER & NAVIGATION
   ============================================================================ */

/* Sticky header - stays at top when scrolling */
.site-header {
  position: sticky;
  top: 0;
  z-index: 999;                     /* High z-index to stay above content */
  background: rgba(255, 255, 255, 0.8);  /* Semi-transparent white */
  backdrop-filter: saturate(180%) blur(12px);  /* Glassmorphism effect */
  border-bottom: 1px solid var(--border);
}

/* Header inner container - flexbox layout for logo and navigation */
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
}

/* Logo styling - clickable link to home */
.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
}

/* Logo mark - circular badge with initials "OI" */
.logo__mark {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  background: var(--text);
  color: #fff;
  border-radius: 9px;
  font-size: 14px;
  letter-spacing: 0.5px;
}

/* Logo text - name next to logo mark */
.logo__text {
  font-weight: 600;
}

/* Navigation menu - horizontal list */
.site-nav ul {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 0;
  margin: 0;
  list-style: none;
}

/* Navigation links - muted color by default */
.site-nav a {
  color: var(--muted);
  font-weight: 500;
}

/* Navigation links - accent color on hover/focus */
.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--accent);
}

/* Mobile navigation toggle button (hamburger menu) - hidden on desktop */
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 10px;
}

/* Hamburger menu bars - three horizontal lines */
.nav-toggle__bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text);
  margin: 5px auto;
}

/* ============================================================================
   HERO SECTION
   ============================================================================
   Introduction section with name, title, description, and call-to-action
   ============================================================================ */
.hero {
  padding: 24px 0 48px;
}

/* Hero grid - two column layout: content (left) and profile (right) */
.hero__grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;  /* Content takes more space than profile */
  gap: 40px;
}

/* Hero subtitle - professional title */
.hero__subtitle {
  color: var(--muted);
  margin: 6px 0 14px;
}

/* Hero description - brief professional summary */
.hero__desc {
  color: var(--muted);
  max-width: 60ch;                   /* Optimal reading width */
}

/* Accent color class - highlights important text */
.accent {
  color: var(--accent);
}

/* Call-to-action buttons container */
.hero__cta {
  display: flex;
  gap: 12px;
  margin: 22px 0 16px;
}

/* ============================================================================
   BUTTONS
   ============================================================================ */

/* Base button styles */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 42px;
  padding: 0 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
  font-weight: 600;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease, color .2s ease;
}

/* Primary button - main action button (blue) */
.btn--primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 8px 20px rgba(0, 123, 255, 0.22);
  border-color: transparent;
}

/* Primary button hover - slight lift and stronger shadow */
.btn--primary:hover,
.btn--primary:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 12px 24px rgba(0, 123, 255, 0.28);
}

/* Ghost button hover - accent color and lift */
.btn--ghost:hover,
.btn--ghost:focus-visible {
  color: var(--accent);
  transform: translateY(-1px);
}

/* CV download button - green gradient with shine effect */
.btn--cv {
  background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 8px 20px rgba(40, 167, 69, 0.22);
  position: relative;
  overflow: hidden;
}

/* Shine effect animation - sliding highlight on hover */
.btn--cv::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  transition: left 0.5s;
}

/* Shine effect - slides across button on hover */
.btn--cv:hover::before {
  left: 100%;
}

/* CV button hover - darker gradient and lift */
.btn--cv:hover,
.btn--cv:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 12px 24px rgba(40, 167, 69, 0.28);
  background: linear-gradient(135deg, #218838 0%, #1ea085 100%);
}

/* ============================================================================
   SOCIAL LINKS
   ============================================================================ */

/* Social media links container */
.social {
  display: flex;
  gap: 12px;
  padding: 0;
  margin: 18px 0 0;
  list-style: none;
}

/* Social link buttons - square icons */
.social a {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  background: #fff;
  transition: border-color .2s ease, color .2s ease, transform .2s ease, box-shadow .2s ease;
}

/* Social link hover - accent color, border, lift, and shadow */
.social a:hover,
.social a:focus-visible {
  color: var(--accent);
  border-color: var(--accent);
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

/* ============================================================================
   META INFORMATION
   ============================================================================ */

/* Contact metadata list (location, phone, email, etc.) */
.meta {
  margin: 0;
  padding: 0;
  list-style: none;
}

.meta li + li { margin-top: 8px; }

.meta a { color: var(--accent); }

/* ============================================================================
   PROFILE IMAGE
   ============================================================================ */

/* Circular profile image with animated rotating border */
.profile-image {
  width: 200px;
  height: 200px;
  margin: 24px;
  border-radius: 50%;                /* Perfect circle */
  overflow: hidden;
  border: 4px solid var(--accent);
  box-shadow: 0 10px 30px rgba(0, 123, 255, 0.2);
  position: relative;
}

/* Animated rotating gradient border */
.profile-image::before {
  content: '';
  position: absolute;
  inset: -4px;                       /* Extends beyond image */
  border-radius: 50%;
  background: linear-gradient(45deg, var(--accent), #0056b3, #004085, var(--accent));
  z-index: -1;                       /* Behind the image */
  animation: rotate 3s linear infinite;  /* Continuous rotation */
}

/* Profile image - covers entire circle */
.profile-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;                 /* Maintains aspect ratio, fills circle */
  transition: transform 0.3s ease;
}

/* Profile image hover - slight zoom effect */
.profile-image:hover img {
  transform: scale(1.05);
}

/* Rotation animation for gradient border */
@keyframes rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* ============================================================================
   SECTIONS
   ============================================================================ */

/* Base section styling - vertical spacing */
.section {
  padding: 16px 0;
}

/* Section title - main heading for each section */
.section__title {
  margin: 0 0 18px;
}

/* Section lead paragraph - introductory text */
.section__lead {
  color: var(--muted);
  max-width: 70ch;                  /* Optimal reading width */
}

/* ============================================================================
   CARDS & GRIDS
   ============================================================================ */

/* Card component - reusable container with shadow and border */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 18px;
  box-shadow: var(--shadow);
}

/* Skills grid - 4 columns on desktop */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

/* Tags and badges - pill-shaped labels for skills/technologies */
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 0;
  margin: 12px 0 0;
  list-style: none;
}

/* Individual tag/badge styling - rounded pills */
.tags li, .badge {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 999px;             /* Fully rounded (pill shape) */
  padding: 6px 10px;
  font-size: 14px;
  color: var(--muted);
}

/* ============================================================================
   TIMELINE (EXPERIENCE SECTION)
   ============================================================================ */

/* Timeline container - vertical list of work experience */
.timeline {
  display: grid;
  gap: 14px;
}

/* Individual timeline item (work experience entry) */
.timeline__item {
  position: relative;
}

/* Timeline header - job title and date range */
.timeline__header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

/* Time period - date range styling */
.time { color: var(--muted); font-size: 14px; }

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

/* Projects grid - 3 columns on desktop */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

/* Project card metadata - technology badges */
.project-card__meta {
  display: flex;
  gap: 8px;
  margin-top: 12px;
  padding: 0 16px;
}

/* ============================================================================
   PROJECT CARDS
   ============================================================================ */

/* Base project card - flex column layout */
.project-card {
  position: relative;
  overflow: hidden;
  border-radius: 10px;
  display: flex;
  flex-direction: column;
}

/* Vibrant project card - blue gradient background with special effects */
.project-card--vibrant {
  background: linear-gradient(135deg, #1e3a8a 0%, #3b82f6 30%, #1d4ed8 70%, #1e40af 100%);
  color: #fff;
  border: none;
  box-shadow: 0 20px 40px rgba(30, 58, 138, 0.3);
}

/* Badges on vibrant cards - semi-transparent white */
.project-card--vibrant .badge {
  background: rgba(255,255,255,0.15);
  border-color: rgba(255,255,255,0.25);
  color: #fff;
}

/* Project card thumbnail - layered background with project image */
.project-card__thumb {
  height: 350px;
  border-radius: 10px;
  margin: -6px -6px 12px;           /* Negative margin to extend beyond card */
  /* Multiple background layers for depth effect */
  background:
    linear-gradient(135deg, rgba(30, 58, 138, 0.4), rgba(59, 130, 246, 0.2)),
    radial-gradient(120px 80px at 20% 30%, rgba(255,255,255,0.15), transparent 60%),
    radial-gradient(120px 80px at 80% 20%, rgba(255,255,255,0.1), transparent 60%),
    radial-gradient(180px 120px at 60% 80%, rgba(255,255,255,0.12), transparent 60%),
    var(--thumb-image, url('img/omnifood-logo.png'));  /* Project image via CSS variable */
  background-size: cover, auto, auto, auto, contain;
  background-position: center, center, center, center, center;
  background-repeat: no-repeat;
  position: relative;
  overflow: hidden;
  filter: brightness(1.1) contrast(1.1) saturate(1.2);  /* Enhanced image appearance */
}

/* Project label - overlay badge on thumbnail */
.project-card__label {
  position: absolute;
  left: 12px;
  bottom: 12px;
  background: rgba(0,0,0,0.35);      /* Semi-transparent dark background */
  border: 1px solid rgba(255,255,255,0.35);
  color: #fff;
  padding: 6px 10px;
  border-radius: 999px;               /* Pill shape */
  font-weight: 600;
  backdrop-filter: blur(4px);         /* Glassmorphism effect */
}

/* Project card body - content area with description and actions */
.project-card__body { 
  padding: 8px 16px; 
  position: relative; 
  display: flex; 
  flex-direction: column; 
  height: 70%; 
}

.project-card__title { margin: 0 0 6px; }

/* Project description - slightly transparent for visual hierarchy */
.project-card__desc { margin: 0 0 12px; opacity: .95;}

/* Project card actions - buttons container at bottom */
.project-card__actions { 
  display: flex; 
  gap: 8px; 
  margin-top: auto;                   /* Push to bottom */
  padding-top: 12px;
  border-top: 1px solid rgba(255,255,255,0.1);  /* Subtle divider */
}

/* ============================================================================
   PROJECT CARD HOVER ANIMATIONS
   ============================================================================ */

/* Animated gradient overlays for hover effect */
.project-card--vibrant::before,
.project-card--vibrant::after {
  content: "";
  position: absolute;
  inset: -30%;                       /* Extends beyond card */
  background: conic-gradient(from 0deg, rgba(255,255,255,0.12), rgba(255,255,255,0) 30%, rgba(255,255,255,0.12) 60%, rgba(255,255,255,0) 100%);
  transform: rotate(0deg);
  transition: transform 1.2s ease;
  pointer-events: none;              /* Doesn't interfere with clicks */
}

/* Blurred version for depth effect */
.project-card--vibrant::after {
  inset: -60%;
  filter: blur(14px);
}

/* Rotate overlays on hover for dynamic effect */
.project-card--vibrant:hover::before,
.project-card--vibrant:focus-within::before {
  transform: rotate(30deg);
}

.project-card--vibrant:hover::after,
.project-card--vibrant:focus-within::after {
  transform: rotate(-18deg);
}

/* Card lift effect on hover */
.project-card--vibrant:hover,
.project-card--vibrant:focus-within {
  transform: translateY(-2px);     /* Slight lift */
  box-shadow: 0 25px 60px rgba(30, 58, 138, 0.4);  /* Stronger shadow */
}

/* Thumbnail enhancement on hover - brighter and slightly zoomed */
.project-card--vibrant:hover .project-card__thumb {
  filter: brightness(1.2) contrast(1.2) saturate(1.3);
  transform: scale(1.02);
}

/* ============================================================================
   CONTACT SECTION
   ============================================================================ */

/* Contact grid - form (left) and info (right) */
.contact-grid {
  display: grid;
  grid-template-columns: 1.2fr .8fr;  /* Form takes more space */
  gap: 16px;
}

/* Form row - two columns for name and email */
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

/* Form field - label and input container */
.form-field { display: grid; gap: 6px; }

/* Form labels */
label { font-weight: 600; }

/* Form inputs and textarea */
input, textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: #fff;
  padding: 10px 12px;
  font: inherit;
  color: var(--text);
}

/* Focus styles - blue outline for accessibility */
input:focus-visible, textarea:focus-visible, .btn:focus-visible, .social a:focus-visible, .site-nav a:focus-visible {
  outline: 2px solid rgba(0, 123, 255, 0.4);
  outline-offset: 2px;
}

/* Form note - disclaimer text */
.form-note { color: var(--muted); font-size: 14px; }

/* Contact information list */
.contact-list { list-style: none; padding: 0; margin: 0; }
.contact-list li + li { margin-top: 8px; }

/* ============================================================================
   FOOTER
   ============================================================================ */

/* Site footer - copyright information */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 22px 0;
  color: var(--muted);
}

/* ============================================================================
   REVEAL ANIMATIONS
   ============================================================================
   Scroll-triggered fade-in and slide-up animations
   ============================================================================ */

/* Hidden by default - will be revealed when scrolled into view */
.reveal { 
  opacity: 0; 
  transform: translateY(8px);       /* Slightly below final position */
  transition: opacity .6s ease, transform .6s ease; 
}

/* Visible state - triggered by JavaScript when element enters viewport */
.reveal.is-visible { 
  opacity: 1; 
  transform: none;                   /* Final position */
}

/* ============================================================================
   RESPONSIVE DESIGN - TABLET (max-width: 980px)
   ============================================================================ */
@media (max-width: 980px) {
  /* Skills grid - single column */
  .skills-grid { grid-template-columns: auto; }
  
  /* Projects grid - 2 columns */
  .projects-grid { grid-template-columns: repeat(2, 1fr); }
  
  /* Hero grid - single column (stacked) */
  .hero__grid { grid-template-columns: 1fr; }
  
  /* Contact grid - single column */
  .contact-grid { grid-template-columns: 1fr; }
  
  /* Smaller profile image */
  .profile-image {
    width: 160px;
    height: 160px;
    margin-bottom: 20px;
  }
}

/* ============================================================================
   RESPONSIVE DESIGN - MOBILE (max-width: 720px)
   ============================================================================ */
@media (max-width: 720px) {
  /* Mobile navigation - fixed overlay menu */
  .site-nav { 
    position: fixed; 
    inset: 64px 16px auto 16px;     /* Positioned below header */
    background: #fff; 
    border: 1px solid var(--border); 
    border-radius: 12px; 
    padding: 12px; 
    display: none;                   /* Hidden by default */
    box-shadow: var(--shadow); 
  }
  
  /* Show navigation when toggled open */
  .site-nav.open { display: block; }
  
  /* Vertical navigation menu */
  .site-nav ul { 
    flex-direction: column; 
    align-items: stretch; 
    gap: 8px; 
  }
  
  /* Show hamburger menu button */
  .nav-toggle { display: inline-grid; place-items: center; }
  
  /* Form fields - single column */
  .form-row { grid-template-columns: 1fr; }
  
  /* Projects grid - single column */
  .projects-grid { grid-template-columns: 1fr; }
  
  /* Smaller profile image */
  .profile-image {
    width: 140px;
    height: 140px;
    margin-bottom: 16px;
  }
  
  /* Mobile font size adjustments for better readability */
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  h3 { font-size: 1.25rem; }
  .hero__subtitle { font-size: 0.9rem; }
  .hero__desc { font-size: 0.9rem; }
  .section__lead { font-size: 0.9rem; }
  .card h3 { font-size: 1.1rem; }
  .timeline__header h3 { font-size: 1.1rem; }
  .project-card__desc { font-size: 0.9rem; }
  .contact-list { font-size: 0.9rem; }
}

/* ============================================================================
   RESPONSIVE DESIGN - SMALL MOBILE (max-width: 480px)
   ============================================================================ */
@media (max-width: 480px) {
  /* Further reduced font sizes for small screens */
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.35rem; }
  h3 { font-size: 1.15rem; }
  .hero__subtitle { font-size: 0.85rem; }
  .hero__desc { font-size: 0.85rem; }
  .section__lead { font-size: 0.85rem; }
  .card h3 { font-size: 1rem; }
  .timeline__header h3 { font-size: 1rem; }
  .project-card__desc { font-size: 0.85rem; }
  .contact-list { font-size: 0.85rem; }
  .btn { font-size: 0.9rem; padding: 8px 16px; }
  .tags li, .badge{font-size: 0.8rem;}
}

/* ============================================================================
   RESPONSIVE DESIGN - VERY SMALL MOBILE (max-width: 400px)
   ============================================================================ */
@media (max-width: 400px) {
  /* Minimum font sizes for very small devices */
  body { font-size: 12px; }
  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.2rem; }
  h3 { font-size: 1rem; }
  .hero__subtitle { font-size: 0.8rem; }
  .hero__desc { font-size: 0.8rem; }
  .section__lead { font-size: 0.8rem; }
  .card h3 { font-size: 0.9rem; }
  .timeline__header h3 { font-size: 0.9rem; }
  .project-card__desc { font-size: 0.8rem; }
  .contact-list { font-size: 0.8rem; }
  .btn { font-size: 0.6rem; padding: 6px 12px; }
  .logo__text { font-size: 0.9rem; }
  .site-nav a { font-size: 0.9rem; }
}

/* ============================================================================
   FAVICON STYLING
   ============================================================================ */

/* Circular favicon styling for profile image icon */
.favicon-circular {
  width: 100px;                      /* Size of the favicon */
  height: 100px;
  border-radius: 50%;                /* Makes it circular */
  object-fit: cover;                 /* Crops the image to fit the circle */
  overflow: hidden;                  /* Hides anything outside the circle */
}