/*!
 * Resume CSS - Modern Redesign
 * Tung Nguyen - AI/ML Engineer Portfolio
 */

/* ===================== CSS VARIABLES ===================== */
:root {
  --primary:        #4f46e5;
  --primary-dark:   #3730a3;
  --primary-light:  #818cf8;
  --accent:         #06b6d4;
  --accent2:        #10b981;
  --bg-dark:        #0f172a;
  --text-muted:     #94a3b8;
  --text-body:      #334155;
  --border:         rgba(99, 102, 241, 0.2);
  --shadow-glow:    0 0 30px rgba(79, 70, 229, 0.25);
  --radius:         12px;
  --transition:     all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', 'Muli', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  padding-top: 54px;
  color: var(--text-body);
  background-color: #f8fafc;
  line-height: 1.7;
  overflow-x: hidden;
}

@media (min-width: 992px) {
  body { padding-top: 0; padding-left: 17rem; }
}

/* ===================== TYPOGRAPHY ===================== */
h1, h2, h3, h4, h5, h6 {
  font-family: 'Saira Extra Condensed', 'Inter', sans-serif;
  font-weight: 700;
  color: #0f172a;
  text-transform: uppercase;
}

h1 { font-size: clamp(2.8rem, 6vw, 5rem); line-height: 1.05; }
h2 { font-size: clamp(2rem, 4vw, 3.2rem); line-height: 1.1; }
h3 { font-size: clamp(1.5rem, 2.5vw, 2rem); }
h4 { font-size: 1.15rem; }
h5 { font-size: 1rem; }

p.lead {
  font-size: 1.08rem;
  font-weight: 400;
  color: #475569;
  line-height: 1.8;
}

strong { color: var(--primary); font-weight: 600; }

a { color: var(--primary); text-decoration: none; transition: var(--transition); }
a:hover, a:focus { color: var(--primary-dark); text-decoration: none; }

/* ===================== SIDEBAR NAV ===================== */
#sideNav {
  background: linear-gradient(160deg, #0f172a 0%, #1a1f3c 60%, #0e1628 100%) !important;
  border-right: 1px solid rgba(99, 102, 241, 0.15);
  box-shadow: 4px 0 30px rgba(0, 0, 0, 0.3);
}

#sideNav .navbar-brand .img-profile {
  border: 3px solid rgba(99, 102, 241, 0.5) !important;
  box-shadow: 0 0 0 6px rgba(99, 102, 241, 0.12), var(--shadow-glow);
  transition: var(--transition);
  max-width: 10rem;
  max-height: 10rem;
}

#sideNav .navbar-brand .img-profile:hover {
  transform: scale(1.05);
  box-shadow: 0 0 0 8px rgba(99, 102, 241, 0.2), 0 0 40px rgba(79, 70, 229, 0.4);
}

#sideNav .navbar-nav .nav-item .nav-link {
  font-weight: 800;
  letter-spacing: 0.08rem;
  text-transform: uppercase;
  font-size: 0.73rem;
  color: #94a3b8 !important;
  padding: 0.6rem 1.2rem;
  border-radius: 8px;
  margin: 2px 8px;
  transition: var(--transition);
  position: relative;
}

#sideNav .navbar-nav .nav-item .nav-link::before {
  content: '';
  position: absolute;
  left: 0; top: 50%;
  transform: translateY(-50%);
  width: 3px; height: 0;
  background: linear-gradient(180deg, var(--primary-light), var(--accent));
  border-radius: 0 3px 3px 0;
  transition: var(--transition);
}

#sideNav .navbar-nav .nav-item .nav-link:hover,
#sideNav .navbar-nav .nav-item .nav-link.active {
  color: #fff !important;
  background: rgba(99, 102, 241, 0.18);
}

#sideNav .navbar-nav .nav-item .nav-link:hover::before,
#sideNav .navbar-nav .nav-item .nav-link.active::before {
  height: 60%;
}

#sideNav .navbar-toggler:focus {
  outline-color: var(--primary-light);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.4);
}

.lang-switcher {
  display: flex;
  gap: 10px;
  align-items: center;
}

.lang-switcher a {
  display: block;
  transition: var(--transition);
  opacity: 0.7;
  line-height: 1;
}

.lang-switcher a:hover {
  opacity: 1;
  transform: scale(1.12);
}

.lang-switcher a.active-lang {
  opacity: 1;
  outline: 2px solid var(--accent);
  border-radius: 4px;
}

.lang-switcher img {
  display: block;
  border-radius: 3px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.4);
}

@media (min-width: 992px) {
  #sideNav {
    text-align: center;
    position: fixed;
    top: 0; left: 0;
    display: flex;
    flex-direction: column;
    width: 17rem;
    height: 100vh;
    overflow-y: auto;
  }
  #sideNav .navbar-brand {
    display: flex;
    margin: auto auto 0;
    padding: 1rem 0.5rem;
    flex-direction: column;
    align-items: center;
  }
  #sideNav .navbar-collapse {
    display: flex !important;
    align-items: flex-start;
    flex-grow: 0;
    width: 100%;
    margin-bottom: auto;
  }
  #sideNav .navbar-collapse .navbar-nav {
    flex-direction: column;
    width: 100%;
  }
  #sideNav .navbar-collapse .navbar-nav .nav-item { display: block; }
  #sideNav .navbar-collapse .navbar-nav .nav-item .nav-link { display: block; }

  .lang-switcher {
    padding: 12px 0 16px;
    justify-content: center;
    border-top: 1px solid rgba(99, 102, 241, 0.15);
    margin-top: 8px;
  }
}

@media (max-width: 991px) {
  .lang-switcher {
    position: absolute;
    right: 70px;
    top: 50%;
    transform: translateY(-50%);
  }
}

/* ===================== SECTIONS ===================== */
section.resume-section {
  padding: 5rem 3rem !important;
  max-width: 75rem;
  position: relative;
}

hr.m-0 { border-color: rgba(99,102,241,0.1); }

@media (min-width: 768px) {
  section.resume-section { min-height: 100vh; }
  section.resume-section .resume-item .resume-date { min-width: 18rem; }
}

@media (min-width: 992px) {
  section.resume-section { padding: 4rem 4rem !important; }
}

/* Section heading */
section.resume-section h3 {
  position: relative;
  display: inline-block;
  padding-bottom: 12px;
  margin-bottom: 2rem !important;
}

section.resume-section h3::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0;
  width: 50px; height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
  transition: width 0.6s ease;
}

section.resume-section:hover h3::after { width: 100%; }

/* ===================== ABOUT SECTION ===================== */
#about {
  background: linear-gradient(135deg, #f0f4ff 0%, #fafbff 60%, #f0fafa 100%);
}

#about h2 {
  background: linear-gradient(135deg, #0f172a 0%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

#about h2 span { color: var(--primary); -webkit-text-fill-color: var(--primary); }

#about .role-title {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 1rem;
  font-family: 'Muli', sans-serif;
}

.subheading {
  text-transform: uppercase;
  font-weight: 500;
  font-family: 'Saira Extra Condensed', sans-serif;
  font-size: 1.35rem;
}

.subheading a { color: var(--primary); font-weight: 600; }
.subheading a:hover { color: var(--accent); }

/* Social Icons */
.social-icons { display: flex; flex-wrap: wrap; gap: 0.75rem; }

.social-icons a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 3rem;
  width: 3rem;
  background: #1e293b;
  color: #fff !important;
  border-radius: 10px;
  font-size: 1.3rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.social-icons a::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  opacity: 0;
  transition: var(--transition);
}

.social-icons a i { position: relative; z-index: 1; }

social-icons a:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 8px 20px rgba(79, 70, 229, 0.4);
}

.social-icons a:hover::before { opacity: 1; }
.social-icons a:last-child { margin-right: 0; }

/* Download Buttons */
.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.88rem;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.btn-download-vn {
  background: linear-gradient(135deg, #f59e0b, #f97316);
  color: #fff;
  box-shadow: 0 4px 15px rgba(245, 158, 11, 0.35);
}

.btn-download-vn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(245, 158, 11, 0.5);
  color: #fff;
}

.btn-download-en {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  box-shadow: 0 4px 15px rgba(79, 70, 229, 0.35);
}

.btn-download-en:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(79, 70, 229, 0.5);
  color: #fff;
}

/* Scroll Down Arrow */
.scroll-down-arrow {
  position: absolute;
  right: 2.5rem;
  bottom: 2.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--primary);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  opacity: 0.65;
  transition: var(--transition);
  animation: float 2.5s ease-in-out infinite;
}

.scroll-down-arrow:hover { opacity: 1; color: var(--primary); }
.scroll-down-arrow i { font-size: 1.6rem; }

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(10px); }
}

/* ===================== SKILLS SECTION ===================== */
#skills { background: #fff; }

.skills-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 0.5rem;
}

.skills-badges img {
  border-radius: 6px;
  transition: var(--transition);
  filter: brightness(0.95) saturate(0.85);
}

.skills-badges img:hover {
  transform: translateY(-3px) scale(1.08);
  filter: brightness(1) saturate(1.2);
  box-shadow: 0 6px 16px rgba(0,0,0,0.15);
}

.skills-category-title {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #0f172a;
  padding: 6px 14px;
  background: linear-gradient(135deg, rgba(79,70,229,0.07), rgba(6,182,212,0.07));
  border-left: 3px solid var(--primary);
  border-radius: 0 8px 8px 0;
  margin: 1.5rem 0 0.75rem;
}

.skills-list {
  list-style: none;
  padding: 0;
  margin-bottom: 0;
}

.skills-list li {
  padding: 10px 0;
  border-bottom: 1px dashed rgba(99, 102, 241, 0.12);
  display: flex;
  align-items: flex-start;
  gap: 10px;
  color: #475569;
  font-size: 0.94rem;
  transition: var(--transition);
}

.skills-list li:last-child { border-bottom: none; }
.skills-list li:hover { color: #0f172a; }

.skill-check {
  flex-shrink: 0;
  width: 20px; height: 20px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-top: 2px;
}

.skill-check i { font-size: 0.58rem; color: #fff; }

/* ===================== PROJECTS SECTION ===================== */
#projects { background: linear-gradient(135deg, #fafbff 0%, #f5f7ff 100%); }

.project-card {
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid rgba(99, 102, 241, 0.12);
  padding: 1.5rem;
  margin-bottom: 1.25rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
  background: linear-gradient(180deg, var(--primary), var(--accent));
  transform: scaleY(0);
  transform-origin: bottom;
  transition: transform 0.4s ease;
}

.project-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 40px rgba(79, 70, 229, 0.12);
  border-color: rgba(99, 102, 241, 0.3);
}

.project-card:hover::before {
  transform: scaleY(1);
  transform-origin: top;
}

.project-card-header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.6rem;
}

.project-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: #0f172a;
  letter-spacing: -0.01em;
  font-family: 'Saira Extra Condensed', sans-serif;
}

.project-tech {
  font-size: 0.75rem;
  color: var(--primary);
  font-weight: 600;
  background: rgba(79, 70, 229, 0.08);
  padding: 3px 10px;
  border-radius: 20px;
  white-space: nowrap;
}

.project-date {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
  padding: 3px 12px;
  background: #f1f5f9;
  border-radius: 20px;
  border: 1px solid #e2e8f0;
}

.project-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 0.75rem;
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--primary) !important;
  padding: 4px 12px;
  border: 1.5px solid rgba(79, 70, 229, 0.3);
  border-radius: 6px;
  transition: var(--transition);
}

.project-link:hover {
  background: var(--primary);
  color: #fff !important;
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.project-desc {
  font-size: 0.9rem;
  color: #64748b;
  line-height: 1.7;
  margin-bottom: 0;
}

/* ===================== EXPERIENCE SECTION ===================== */
#experience { background: #fff; }

.experience-timeline {
  position: relative;
  padding-left: 2rem;
}

.experience-timeline::before {
  content: '';
  position: absolute;
  left: 4px; top: 12px; bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--primary) 0%, rgba(79,70,229,0.08) 100%);
}

.exp-item {
  position: relative;
  margin-bottom: 1.75rem;
}

.exp-dot {
  position: absolute;
  left: -2rem;
  top: 8px;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: 0 0 0 3px rgba(79,70,229,0.18), 0 0 0 6px rgba(79,70,229,0.06);
}

.exp-card {
  background: #f8fafc;
  border: 1px solid rgba(99, 102, 241, 0.1);
  border-radius: var(--radius);
  padding: 1.2rem 1.4rem;
  transition: var(--transition);
}

.exp-card:hover {
  background: #fff;
  border-color: rgba(99, 102, 241, 0.25);
  box-shadow: 0 8px 24px rgba(79, 70, 229, 0.08);
  transform: translateX(4px);
}

.exp-company {
  font-size: 1rem;
  font-weight: 700;
  color: #0f172a;
  font-family: 'Saira Extra Condensed', sans-serif;
  font-size: 1.2rem;
  letter-spacing: 0.02em;
  margin-bottom: 2px;
}

.exp-company a {
  font-size: 0.72rem;
  font-weight: 400;
  font-style: italic;
  color: var(--text-muted) !important;
  margin-left: 8px;
  text-transform: none;
  font-family: 'Muli', sans-serif;
}

.exp-company a:hover { color: var(--primary) !important; }

.exp-position {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 4px;
}

.exp-date {
  display: inline-block;
  font-size: 0.73rem;
  font-weight: 600;
  color: var(--text-muted);
  background: rgba(79,70,229,0.07);
  padding: 2px 10px;
  border-radius: 20px;
  margin-bottom: 8px;
  border: 1px solid rgba(79,70,229,0.12);
}

.exp-desc {
  font-size: 0.88rem;
  color: #64748b;
  line-height: 1.7;
  margin: 0;
}

/* ===================== EDUCATION SECTION ===================== */
#education { background: linear-gradient(135deg, #fafbff 0%, #f0fdf4 100%); }

.edu-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 1.4rem;
  margin-bottom: 1.25rem;
  border: 1px solid rgba(16, 185, 129, 0.15);
  transition: var(--transition);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  flex-wrap: wrap;
}

.edu-card:hover {
  box-shadow: 0 10px 28px rgba(16, 185, 129, 0.1);
  border-color: rgba(16, 185, 129, 0.3);
  transform: translateY(-3px);
}

.edu-school {
  font-size: 1.1rem;
  font-weight: 700;
  color: #0f172a;
  font-family: 'Saira Extra Condensed', sans-serif;
  letter-spacing: 0.02em;
  margin-bottom: 4px;
}

.edu-major {
  font-size: 0.88rem;
  color: var(--accent2);
  font-weight: 600;
}

.edu-date {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  padding: 3px 12px;
  background: #f0fdf4;
  border-radius: 20px;
  border: 1px solid rgba(16,185,129,0.2);
  white-space: nowrap;
  flex-shrink: 0;
}

/* Competition */
.competition-card {
  background: linear-gradient(135deg, rgba(245,158,11,0.06), rgba(249,115,22,0.06));
  border: 1px solid rgba(245, 158, 11, 0.2);
  border-radius: var(--radius);
  padding: 1.25rem 1.4rem;
  margin-bottom: 1.25rem;
  transition: var(--transition);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  flex-wrap: wrap;
}

.competition-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 25px rgba(245, 158, 11, 0.15);
}

.competition-title {
  font-size: 1rem;
  font-weight: 700;
  color: #0f172a;
  font-family: 'Saira Extra Condensed', sans-serif;
  margin-bottom: 4px;
  letter-spacing: 0.02em;
}

.competition-desc {
  font-size: 0.88rem;
  color: #64748b;
}

.competition-date {
  font-size: 0.75rem;
  font-weight: 600;
  color: #d97706;
  padding: 3px 12px;
  background: rgba(245,158,11,0.1);
  border-radius: 20px;
  white-space: nowrap;
  flex-shrink: 0;
}

/* Certifications */
.cert-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.cert-list > li {
  padding: 8px 0;
  border-bottom: 1px dashed rgba(99,102,241,0.1);
  font-size: 0.9rem;
}

.cert-list > li:last-child { border-bottom: none; }

.cert-list a {
  color: var(--primary);
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition);
}

.cert-list a:hover { color: var(--accent); gap: 10px; }

/* Toggle */
.toggle-list { list-style: none; padding: 0; }

.toggle-item {
  display: none;
  padding-left: 16px;
  border-left: 2px solid rgba(99,102,241,0.2);
  margin: 6px 0;
}

.toggle-button {
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  color: var(--primary);
  font-weight: 600;
  font-size: 0.88rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition);
}

.toggle-button:hover { color: var(--accent); }

.toggle-arrow::before {
  content: '▶';
  font-size: 0.6rem;
  transition: transform 0.3s ease;
  display: inline-block;
  color: var(--primary-light);
}

.toggle-arrow.open::before { transform: rotate(90deg); }

/* ===================== SCROLL ANIMATION ===================== */
.fade-in-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ===================== UTILITY ===================== */
.text-primary { color: var(--primary) !important; }
.bg-primary { background: var(--bg-dark) !important; }

/* ===================== SCROLLBAR ===================== */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: #f1f5f9; }
::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, var(--primary), var(--accent));
  border-radius: 3px;
}

/* ===================== SELECTION ===================== */
::selection { background: rgba(79,70,229,0.18); color: var(--primary-dark); }

/* ===================== RESPONSIVE ===================== */
@media (max-width: 767px) {
  section.resume-section { padding: 3rem 1.5rem !important; }
  .project-card-header { flex-direction: column; }
  .scroll-down-arrow { display: none; }
  .edu-card, .competition-card { flex-direction: column; }
}