/* ==========================================================================
   Brittany Chiang v4 inspired portfolio — Bootstrap custom theme
   ========================================================================== */

:root {
  --navy: #0a192f;
  --light-navy: #112240;
  --lightest-navy: #233554;
  --dark-navy: #020c1b;
  --slate: #8892b0;
  --light-slate: #a8b2d1;
  --lightest-slate: #ccd6f6;
  --white: #e6f1ff;
  --green: #64ffda;
  --green-tint: rgba(100, 255, 218, 0.1);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;
  --fz-xs: 13px;
  --fz-sm: 14px;
  --fz-md: 16px;
  --fz-lg: 18px;
  --fz-xl: 20px;
  --fz-xxl: 22px;
  --fz-heading: 32px;
  --border-radius: 4px;
  --transition: all 0.25s cubic-bezier(0.645, 0.045, 0.355, 1);
  --nav-height: 100px;
  --side-padding: 50px;
  --rail-width: 42px;
  --tab-height: 42px;
  --easing: cubic-bezier(0.645, 0.045, 0.355, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--fz-lg);
  line-height: 1.6;
  color: var(--slate);
  background-color: var(--navy);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

a:hover {
  color: var(--green);
}

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

::selection {
  background-color: var(--lightest-navy);
  color: var(--lightest-slate);
}

/* Layout */
.main-content {
  width: 100%;
  min-height: 100vh;
  padding: 0 25px 100px;
}

@media (min-width: 768px) {
  .main-content {
    padding: 0 50px 100px;
  }
}

@media (min-width: 1080px) {
  .main-content {
    padding: 0 150px 100px;
  }
}

.section {
  max-width: 1000px;
  margin: 0 auto;
  padding: 100px 0;
}

.section:first-of-type:not(.hero-section) {
  padding-top: 0;
}

/* Header — cố định phía trên */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1040;
  height: var(--nav-height);
  background-color: rgba(10, 25, 47, 0.85);
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  margin: 0 auto;
  padding: 0 25px;
}

@media (min-width: 768px) {
  .header-inner {
    padding: 0 50px;
  }
}

.header-logo {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  flex-shrink: 0;
  color: var(--green);
}

.header-logo:hover {
  transform: translateY(-2px);
}

.header-logo img {
  display: block;
}

/* Nav ngang trên header */
.header-nav .nav-list {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.header-nav .nav-link {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 10px;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--light-slate);
  transition: var(--transition);
}

.header-nav .nav-link:hover,
.header-nav .nav-link.active {
  color: var(--green);
}

.nav-number {
  color: var(--green);
}

.nav-resume {
  margin-left: 12px;
}

.nav-resume .btn-outline-accent {
  padding: 0.6rem 1rem;
  font-size: var(--fz-xs);
}

/* Mobile nav */
.mobile-nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 42px;
  height: 42px;
  padding: 8px;
  background: transparent;
  border: none;
  cursor: pointer;
}

@media (max-width: 991.98px) {
  .mobile-nav-toggle {
    position: fixed;
    top: 14px;
    right: 20px;
    z-index: 1050;
    pointer-events: auto;
  }
}

.mobile-nav-toggle .bar {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--green);
  border-radius: 2px;
  transition: var(--transition);
}

.mobile-nav-toggle.is-active .bar:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.mobile-nav-toggle.is-active .bar:nth-child(2) {
  opacity: 0;
}

.mobile-nav-toggle.is-active .bar:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

@media (max-width: 991.98px) {
  .header-nav {
    position: fixed;
    top: 0;
    right: 0;
    z-index: 2;
    width: min(75vw, 320px);
    height: 100vh;
    padding: 80px 40px 40px;
    background-color: var(--light-navy);
    box-shadow: -10px 0 30px -15px rgba(2, 12, 27, 0.7);
    transform: translateX(100%);
    transition: transform 0.3s var(--easing);
    overflow-y: auto;
    pointer-events: auto;
  }

  body.nav-open .header-nav {
    transform: translateX(0);
  }

  .nav-close {
    position: absolute;
    top: 28px;
    right: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    padding: 0;
    color: var(--green);
    font-size: 24px;
    background: transparent;
    border: none;
    cursor: pointer;
    transition: var(--transition);
  }

  .nav-close:hover {
    transform: rotate(90deg);
  }

  .header-nav .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }

  .header-nav .nav-link {
    width: 100%;
    padding: 12px 0;
    font-size: var(--fz-sm);
  }

  .nav-resume {
    margin-left: 0;
    margin-top: 24px;
  }
}

@media (min-width: 992px) {
  .mobile-nav-toggle {
    display: none;
  }
}

.nav-overlay {
  position: fixed;
  inset: 0;
  z-index: 1035;
  background: rgba(2, 12, 27, 0.7);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: var(--transition);
}

body.nav-open {
  overflow: hidden;
}

body.nav-open .site-header {
  z-index: 1045;
}

body.nav-open .nav-overlay {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

/* Side rails — desktop */
@media (min-width: 1080px) {
  .header-inner {
    padding-left: var(--side-padding);
    padding-right: var(--side-padding);
  }

  .header-logo {
    width: var(--rail-width);
    justify-content: center;
  }
}

/* Social cố định bên trái */
.fixed-social {
  display: none;
  position: fixed;
  bottom: 0;
  left: var(--side-padding);
  z-index: 10;
  width: var(--rail-width);
  flex-direction: column;
  align-items: center;
}

@media (min-width: 1080px) {
  .fixed-social {
    display: flex;
  }
}

.fixed-social .social-list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  width: 100%;
  margin: 0;
  padding: 0;
}

.fixed-social .social-list::after {
  content: '';
  display: block;
  width: 1px;
  height: 90px;
  background-color: var(--light-slate);
}

.fixed-social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  color: var(--light-slate);
  font-size: 20px;
}

.fixed-social a:hover {
  color: var(--green);
  transform: translateY(-3px);
}

/* Email cố định bên phải */
.fixed-email {
  display: none;
  position: fixed;
  bottom: 0;
  right: var(--side-padding);
  z-index: 10;
  width: var(--rail-width);
  flex-direction: column;
  align-items: center;
}

@media (min-width: 1080px) {
  .fixed-email {
    display: flex;
  }
}

.fixed-email a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: var(--rail-width);
  margin-bottom: 20px;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  letter-spacing: 0.1em;
  line-height: 1;
  color: var(--light-slate);
  writing-mode: vertical-rl;
  text-orientation: mixed;
  white-space: nowrap;
}

.fixed-email::after {
  content: '';
  display: block;
  width: 1px;
  height: 90px;
  flex-shrink: 0;
  background-color: var(--light-slate);
}

.fixed-email a:hover {
  color: var(--green);
  transform: translateY(-3px);
}

/* Hero */
.section.hero-section {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  padding-top: calc(var(--nav-height) + 24px);
  padding-bottom: 60px;
}

.hero-greeting {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: var(--fz-md);
  color: var(--green);
}

.hero-name {
  margin-bottom: 8px;
  font-size: clamp(40px, 8vw, 80px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--lightest-slate);
}

.hero-tagline {
  margin-bottom: 24px;
  font-size: clamp(30px, 6vw, 60px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--slate);
}

.hero-description {
  max-width: 540px;
  margin-bottom: 48px;
  font-size: var(--fz-xl);
  line-height: 1.5;
}

/* Buttons */
.btn-outline-accent {
  display: inline-block;
  padding: 1rem 1.75rem;
  font-family: var(--font-mono);
  font-size: var(--fz-sm);
  color: var(--green);
  background: transparent;
  border: 1px solid var(--green);
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.btn-outline-accent:hover,
.btn-outline-accent:focus {
  color: var(--green);
  background-color: var(--green-tint);
  border-color: var(--green);
  transform: translateY(-3px);
  box-shadow: none;
}

/* Section headings */
.section-heading {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 48px;
  font-size: clamp(24px, 5vw, var(--fz-heading));
  font-weight: 600;
  color: var(--lightest-slate);
  white-space: nowrap;
}

.section-heading::after {
  content: '';
  display: block;
  width: 100%;
  max-width: 300px;
  height: 1px;
  margin-left: 16px;
  background-color: var(--lightest-navy);
}

.section-number {
  font-family: var(--font-mono);
  font-size: clamp(16px, 3vw, var(--fz-xl));
  font-weight: 400;
  color: var(--green);
}

/* About */
.about-text p {
  margin-bottom: 16px;
}

.skills-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(140px, 200px));
  gap: 0 12px;
  margin-top: 20px;
  padding: 0;
  list-style: none;
}

.skills-list li {
  position: relative;
  padding-left: 20px;
  font-family: var(--font-mono);
  font-size: var(--fz-sm);
  color: var(--light-slate);
}

.skills-list li::before {
  content: '▹';
  position: absolute;
  left: 0;
  color: var(--green);
}

.about-image-wrapper {
  display: flex;
  justify-content: center;
}

@media (min-width: 992px) {
  .about-image-wrapper {
    justify-content: flex-end;
  }
}

.about-image-frame {
  position: relative;
  width: 100%;
  max-width: 280px;
  border-radius: var(--border-radius);
}

.about-image-frame::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 2;
  border: 2px solid var(--green);
  border-radius: var(--border-radius);
  mix-blend-mode: normal;
  transition: var(--transition);
  transform: translate(16px, 16px);
}

.about-image-frame::after {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 1;
  border-radius: var(--border-radius);
  background-color: var(--green);
  mix-blend-mode: multiply;
  transition: var(--transition);
}

.about-image-frame:hover::before {
  transform: translate(12px, 12px);
}

.about-image-frame:hover::after {
  background-color: transparent;
}

.about-image {
  position: relative;
  z-index: 3;
  display: block;
  width: 100%;
  border-radius: var(--border-radius);
  filter: grayscale(100%) contrast(1.1);
  transition: var(--transition);
  object-fit: cover;
  aspect-ratio: 1;
  background: linear-gradient(135deg, var(--light-navy), var(--lightest-navy));
}

.about-image-frame:hover .about-image {
  filter: none;
}

/* Experience tabs */
.experience-tabs {
  gap: 0;
}

.experience-tabs .nav-link {
  display: flex;
  align-items: center;
  width: 100%;
  min-height: var(--tab-height);
  padding: 0 20px;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--light-slate);
  text-align: left;
  background: transparent;
  border: none;
  border-left: 2px solid var(--lightest-navy);
  border-radius: 0;
  transition: var(--transition);
}

.experience-tabs .nav-link:hover {
  color: var(--green);
  background-color: var(--light-navy);
}

.experience-tabs .nav-link.active {
  color: var(--green);
  background-color: var(--light-navy);
  border-left-color: var(--green);
}

.job-title {
  margin-bottom: 4px;
  font-size: var(--fz-xxl);
  font-weight: 500;
  color: var(--lightest-slate);
}

.job-company {
  color: var(--green);
}

.job-range {
  margin-bottom: 24px;
  font-family: var(--font-mono);
  font-size: var(--fz-sm);
  color: var(--light-slate);
}

.job-details {
  padding-left: 20px;
}

.job-details li {
  position: relative;
  margin-bottom: 10px;
  padding-left: 4px;
  font-size: var(--fz-md);
  color: var(--light-slate);
}

.job-details li::marker {
  color: var(--green);
  content: '▹';
}

/* Featured projects */
.featured-project {
  margin-bottom: 100px;
}

.featured-project:last-of-type {
  margin-bottom: 80px;
}

.project-label {
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: var(--fz-sm);
  color: var(--green);
}

.project-title {
  margin-bottom: 20px;
  font-size: clamp(22px, 4vw, 28px);
  font-weight: 600;
  color: var(--lightest-slate);
}

.project-title a:hover {
  color: var(--green);
}

.project-description {
  position: relative;
  z-index: 2;
  padding: 24px;
  margin-bottom: 20px;
  background-color: var(--light-navy);
  border-radius: var(--border-radius);
  box-shadow: 0 10px 30px -15px rgba(2, 12, 27, 0.7);
}

.project-description p {
  margin: 0;
  font-size: var(--fz-md);
  color: var(--light-slate);
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 16px;
}

.project-tech li {
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--slate);
}

.project-links {
  display: flex;
  gap: 16px;
}

.project-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  color: var(--light-slate);
}

.project-links a:hover {
  color: var(--green);
  transform: translateY(-2px);
}

.project-image-link {
  display: block;
  position: relative;
  border-radius: var(--border-radius);
  overflow: hidden;
}

.project-image {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 10;
  border-radius: var(--border-radius);
  box-shadow: 0 10px 30px -15px rgba(2, 12, 27, 0.7);
  transition: var(--transition);
}

.project-image::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 1;
  background-color: var(--green);
  mix-blend-mode: screen;
  opacity: 0.25;
  transition: var(--transition);
}

.project-image-link:hover .project-image {
  filter: none;
  transform: translateY(-4px);
}

.project-image-link:hover .project-image::before {
  opacity: 0;
}

.project-image-1 {
  background: linear-gradient(135deg, #1d3557 0%, #457b9d 50%, #64ffda 100%);
}

.project-image-2 {
  background: linear-gradient(135deg, #2d1b69 0%, #6930c3 50%, #64ffda 100%);
}

.project-image-3 {
  background: linear-gradient(135deg, #0d2818 0%, #2d6a4f 50%, #64ffda 100%);
}

/* Other projects */
.other-projects-heading {
  margin-bottom: 40px;
  font-size: clamp(22px, 4vw, 28px);
  font-weight: 600;
  color: var(--lightest-slate);
  text-align: center;
}

.project-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 32px 28px;
  background-color: var(--light-navy);
  border-radius: var(--border-radius);
  transition: var(--transition);
  box-shadow: 0 10px 30px -15px rgba(2, 12, 27, 0.7);
}

.project-card:hover {
  transform: translateY(-7px);
  box-shadow: 0 20px 30px -15px rgba(2, 12, 27, 0.7);
}

.project-card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 24px;
}

.project-card-top > .bi-folder {
  font-size: 40px;
  color: var(--green);
}

.project-card-links {
  display: flex;
  gap: 12px;
  font-size: 18px;
  color: var(--light-slate);
}

.project-card-title {
  margin-bottom: 12px;
  font-size: var(--fz-xl);
  font-weight: 600;
  color: var(--lightest-slate);
}

.project-card-desc {
  flex: 1;
  margin-bottom: 20px;
  font-size: var(--fz-md);
  line-height: 1.5;
  color: var(--light-slate);
}

.project-card-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.project-card-tech li {
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--slate);
}

/* Contact */
.contact-section {
  text-align: center;
  padding-bottom: 80px;
}

.contact-label {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: var(--fz-md);
  color: var(--green);
}

.contact-heading {
  margin-bottom: 24px;
  font-size: clamp(36px, 6vw, 60px);
  font-weight: 700;
  color: var(--lightest-slate);
}

.contact-text {
  max-width: 600px;
  margin: 0 auto 48px;
  font-size: var(--fz-xl);
}

/* Footer */
.site-footer {
  max-width: 1000px;
  margin: 0 auto;
  padding: 24px 0 40px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--light-slate);
}

.site-footer a {
  color: var(--green);
}

.site-footer a:hover {
  text-decoration: underline;
}

/* Mobile spacing */
@media (max-width: 767.98px) {
  :root {
    --nav-height: 70px;
  }

  .main-content {
    padding: 0 20px 40px;
  }

  .section {
    padding: 30px 0;
  }

  .section.hero-section {
    min-height: auto;
    padding-top: calc(var(--nav-height) + 20px);
    padding-bottom: 30px;
  }

  .hero-greeting {
    margin-bottom: 12px;
  }

  .hero-name {
    margin-bottom: 6px;
  }

  .hero-tagline {
    margin-bottom: 16px;
  }

  .hero-description {
    margin-bottom: 28px;
    font-size: var(--fz-md);
  }

  .btn-outline-accent {
    padding: 0.75rem 1.25rem;
  }

  .section-heading {
    gap: 8px;
    margin-bottom: 24px;
    white-space: normal;
  }

  .section-heading::after {
    max-width: 80px;
    margin-left: 10px;
  }

  .about-text p {
    margin-bottom: 12px;
  }

  .skills-list {
    margin-top: 12px;
    gap: 0 8px;
  }

  .about-image-wrapper {
    margin-top: 8px;
  }

  .about-image-frame::before {
    transform: translate(10px, 10px);
  }

  .section .row.g-4 {
    --bs-gutter-y: 1rem;
  }

  .job-range {
    margin-bottom: 16px;
  }

  .job-details li {
    margin-bottom: 8px;
  }

  .featured-project {
    margin-bottom: 36px;
  }

  .featured-project:last-of-type {
    margin-bottom: 30px;
  }

  .project-title {
    margin-bottom: 12px;
  }

  .project-description {
    padding: 16px;
    margin-bottom: 14px;
  }

  .project-tech {
    gap: 10px;
    margin-bottom: 12px;
  }

  .project-image {
    margin-bottom: 4px;
  }

  .other-projects-heading {
    margin-bottom: 24px;
  }

  .project-card {
    padding: 20px 18px;
  }

  .project-card-top {
    margin-bottom: 16px;
  }

  .project-card-top > .bi-folder {
    font-size: 32px;
  }

  .project-card-desc {
    margin-bottom: 14px;
  }

  .section .text-center.mt-5 {
    margin-top: 1.5rem !important;
  }

  .contact-section {
    padding-bottom: 30px;
  }

  .contact-label {
    margin-bottom: 12px;
  }

  .contact-heading {
    margin-bottom: 16px;
  }

  .contact-text {
    margin-bottom: 28px;
    font-size: var(--fz-md);
  }

  .site-footer {
    padding: 16px 0 24px;
  }
}

@media (min-width: 768px) and (max-width: 991.98px) {
  .section {
    padding: 60px 0;
  }

  .featured-project {
    margin-bottom: 60px;
  }

  .featured-project:last-of-type {
    margin-bottom: 50px;
  }

  .section-heading {
    margin-bottom: 36px;
  }

  .contact-section {
    padding-bottom: 50px;
  }
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s var(--easing), transform 0.6s var(--easing);
}

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

/* Scrollbar */
::-webkit-scrollbar {
  width: 12px;
}

::-webkit-scrollbar-track {
  background: var(--dark-navy);
}

::-webkit-scrollbar-thumb {
  background-color: var(--dark-navy);
  border: 3px solid var(--dark-navy);
  border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
  background-color: var(--lightest-navy);
}