/* Premium Standalone Portfolio Theme - Mobile First Dark Slate & Teal Style
   Author: Xiaoliang Liang (梁小梁)
*/

:root {
  --bg-main: #0f172a;
  --bg-surface: #1e293b;
  --bg-glass: rgba(15, 23, 42, 0.9);
  --border-color: rgba(71, 85, 105, 0.4);
  --border-focus: #14b8a6;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --primary-gradient: linear-gradient(135deg, #14b8a6, #06b6d4);
  --teal-accent: #2dd4bf;
  --teal-glow: rgba(20, 184, 166, 0.15);
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.15), 0 2px 4px -1px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.25), 0 4px 6px -2px rgba(0,0,0,0.15);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.35), 0 10px 10px -5px rgba(0,0,0,0.2);
}

/* Reset & Base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--bg-main);
  color: var(--text-primary);
  font-size: 16px; /* Mobile first: increased base font size */
}

@media (min-width: 768px) {
  html {
    font-size: 17.5px; /* Scaled up for tablet and desktop */
  }
}

body {
  line-height: 1.65;
  overflow-x: hidden;
  padding-bottom: 2rem;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.3s;
}

/* Utility Layouts */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.section-padding {
  padding: 4rem 0; /* Responsive section padding */
}

@media (min-width: 768px) {
  .section-padding {
    padding: 6.5rem 0;
  }
}

.text-gradient {
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* Sticky Header & Nav (Responsive Mobile-First) */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 0.9rem 0;
}

.header .nav-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

@media (min-width: 768px) {
  .header .nav-container {
    flex-direction: row;
    justify-content: space-between;
    gap: 0;
  }
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.logo-badge {
  background: var(--primary-gradient);
  color: #fff;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.72rem;
  text-transform: uppercase;
  font-weight: 800;
}

.nav-links {
  display: flex;
  gap: 1.1rem;
  list-style: none;
  overflow-x: auto;
  width: 100%;
  justify-content: center;
  padding: 0.2rem 0;
  -webkit-overflow-scrolling: touch;
}

.nav-links::-webkit-scrollbar {
  display: none; /* Hide scrollbar for cleaner look on mobile */
}

@media (min-width: 768px) {
  .nav-links {
    gap: 1.85rem;
    overflow-x: visible;
    width: auto;
    justify-content: flex-end;
  }
}

.nav-links a {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-secondary);
  white-space: nowrap;
}

@media (min-width: 768px) {
  .nav-links a {
    font-size: 0.98rem;
  }
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--teal-accent);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.75rem 1.5rem;
  font-size: 0.92rem;
  font-weight: 700;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border: 1px solid transparent;
}

@media (min-width: 768px) {
  .btn {
    padding: 0.8rem 1.7rem;
    font-size: 0.98rem;
  }
}

.btn-primary {
  background: var(--primary-gradient);
  color: #fff;
  box-shadow: 0 4px 10px var(--teal-glow);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 14px var(--teal-glow);
  filter: brightness(1.1);
}

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

.btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.05);
  border-color: var(--teal-accent);
  transform: translateY(-1px);
}

/* Active Status Pill */
.hero-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.9rem;
  background-color: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.25);
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 700;
  color: #34d399; /* Soft green active text */
  margin-bottom: 1.5rem;
}

.status-dot {
  width: 8px;
  height: 8px;
  background-color: #10b981;
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7);
  }
  70% {
    transform: scale(1);
    box-shadow: 0 0 0 6px rgba(16, 185, 129, 0);
  }
  100% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0);
  }
}

/* Hero Actions Spacing & Centering */
.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center; /* Centered on mobile */
}

@media (min-width: 900px) {
  .hero-actions {
    justify-content: flex-start; /* Left-aligned on desktop */
  }
}

/* Hero Section with Avatar Grid (Responsive Stack) */
.hero {
  position: relative;
  overflow: hidden;
  padding: 1.5rem 0; /* Compact mobile padding */
}

@media (min-width: 768px) {
  .hero {
    padding: 5.5rem 0;
  }
}

.hero::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, var(--teal-glow) 0%, transparent 70%);
  z-index: -1;
  pointer-events: none;
}

.hero-grid {
  display: flex;
  flex-direction: column-reverse; /* Avatar first, then text content on mobile */
  gap: 1.2rem; /* Compact mobile gap */
  align-items: center;
  text-align: center;
}

@media (min-width: 900px) {
  .hero-grid {
    display: grid;
    grid-template-columns: 1.35fr 0.65fr;
    text-align: left;
    gap: 3.5rem;
  }
}

.hero-content {
  width: 100%;
}

.hero-eyebrow {
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--teal-accent);
  margin-bottom: 1rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.3rem 0.75rem;
  background-color: rgba(20, 184, 166, 0.1);
  border-radius: 9999px;
  border: 1px solid rgba(20, 184, 166, 0.2);
}

.hero-title {
  font-size: 1.95rem; /* Safe mobile title size */
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 0.75rem; /* Compact mobile margin */
  letter-spacing: -0.01em;
}

@media (min-width: 768px) {
  .hero-title {
    font-size: 2.5rem;
    margin-bottom: 1.1rem;
  }
}

@media (min-width: 1024px) {
  .hero-title {
    font-size: 3.0rem;
  }
}

.hero-subtitle {
  font-size: 0.98rem;
  color: var(--text-secondary);
  margin-bottom: 1.0rem; /* Compact mobile margin */
  line-height: 1.6;
}

@media (min-width: 768px) {
  .hero-subtitle {
    font-size: 1.08rem;
    margin-bottom: 1.85rem;
  }
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1.0rem; /* Compact mobile margin */
}

@media (min-width: 768px) {
  .hero-tags {
    margin-bottom: 1.85rem;
  }
}

@media (min-width: 900px) {
  .hero-tags {
    justify-content: flex-start;
  }
}

.hero-tag {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 0.3rem 0.6rem;
  border-radius: 4px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
}

/* Avatar Compatibility (Handles white background gracefully) */
.hero-avatar-area {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
}

.avatar-wrapper {
  position: relative;
  width: 150px; /* Highly optimized mobile size */
  height: 150px;
  border-radius: 50%;
  padding: 4px;
  background-color: #ffffff;
  border: 4px solid var(--border-color);
  box-shadow: var(--shadow-lg), 0 0 20px rgba(20, 184, 166, 0.25);
  overflow: hidden;
  transition: transform 0.3s;
}

.avatar-wrapper:hover {
  transform: scale(1.03);
  border-color: var(--teal-accent);
}

@media (min-width: 768px) {
  .avatar-wrapper {
    width: 190px;
    height: 190px;
  }
}

@media (min-width: 1024px) {
  .avatar-wrapper {
    width: 220px;
    height: 220px;
    padding: 6px;
    border-width: 5px;
  }
}

.avatar-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 50%;
}

/* Sections Head */
.section-header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.section-eyebrow {
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--teal-accent);
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.section-title {
  font-size: 1.85rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

@media (min-width: 768px) {
  .section-title {
    font-size: 2.25rem;
  }
}

.section-divider {
  width: 50px;
  height: 3px;
  background: var(--primary-gradient);
  margin: 0.8rem auto 0;
  border-radius: 9999px;
}

/* Grid & Cards layout (Mobile First) */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .card-grid {
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
  }
}

.card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.75rem;
  transition: all 0.3s;
  position: relative;
  overflow: hidden;
}

@media (min-width: 768px) {
  .card {
    padding: 2.2rem;
  }
}

.card:hover {
  transform: translateY(-2px);
  border-color: var(--teal-accent);
  box-shadow: var(--shadow-md), 0 0 10px rgba(20, 184, 166, 0.1);
}

/* Advantage Section with Inline Icon & Title */
.advantage-header {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  margin-bottom: 0.85rem;
}

.advantage-icon {
  font-size: 2.2rem; /* Significantly enlarged advantage icons */
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.advantage-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0;
}

@media (min-width: 768px) {
  .advantage-title {
    font-size: 1.3rem;
  }
}

.advantage-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

@media (min-width: 768px) {
  .advantage-desc {
    font-size: 1.0rem;
  }
}

/* Timeline / Experience (Responsive adjustments) */
.timeline {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

.timeline::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 15px;
  width: 2px;
  background-color: var(--border-color);
}

.timeline-item {
  position: relative;
  padding-left: 38px;
  margin-bottom: 2.8rem;
}

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

.timeline-marker {
  position: absolute;
  left: 7px;
  top: 6px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background-color: var(--bg-main);
  border: 3px solid var(--teal-accent);
  box-shadow: 0 0 6px var(--teal-accent);
  z-index: 2;
  transition: all 0.3s;
}

.timeline-item:hover .timeline-marker {
  background-color: var(--teal-accent);
  transform: scale(1.1);
}

.timeline-content {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 1.6rem;
  border-radius: 10px;
}

@media (min-width: 768px) {
  .timeline-content {
    padding: 2rem;
  }
}

.timeline-header {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 0.75rem;
}

@media (min-width: 768px) {
  .timeline-header {
    flex-direction: row;
    justify-content: space-between;
    align-items: flex-start;
    gap: 0.5rem;
  }
}

.timeline-title {
  font-size: 1.2rem;
  font-weight: 700;
}

@media (min-width: 768px) {
  .timeline-title {
    font-size: 1.3rem;
  }
}

.timeline-meta {
  font-size: 0.88rem;
  color: var(--text-muted);
  font-weight: 600;
  display: flex;
  gap: 0.5rem;
}

.timeline-date {
  font-size: 0.82rem;
  color: var(--teal-accent);
  font-weight: 700;
  background-color: rgba(20, 184, 166, 0.1);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  align-self: flex-start;
}

.timeline-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

@media (min-width: 768px) {
  .timeline-desc {
    font-size: 1.0rem;
  }
}

.timeline-achievements {
  margin-top: 0.75rem;
  padding-left: 1.1rem;
  font-size: 0.88rem;
  color: var(--text-secondary);
}

@media (min-width: 768px) {
  .timeline-achievements {
    font-size: 0.92rem;
  }
}

.timeline-achievements li {
  margin-bottom: 0.4rem;
}

/* Standalone Project Card Style (Clean, Responsive) */
.project-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 1.6rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--border-color); /* Set 4px left border to avoid content shift */
  background-color: var(--bg-surface);
  transition: all 0.3s;
}

@media (min-width: 768px) {
  .project-card {
    padding: 2.2rem;
  }
}

.project-card:hover {
  transform: translateY(-2px);
  border-left-color: var(--teal-accent); /* Only transition the border color on hover */
  box-shadow: var(--shadow-md), 0 0 10px rgba(20, 184, 166, 0.1);
}

.project-tag-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 1rem;
}

.project-tag {
  background-color: rgba(6, 182, 212, 0.1);
  color: #06b6d4;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
}

.project-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

@media (min-width: 768px) {
  .project-title {
    font-size: 1.3rem;
  }
}

.project-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  flex-grow: 1;
  margin-bottom: 1.5rem;
  line-height: 1.55;
}

@media (min-width: 768px) {
  .project-desc {
    font-size: 1.0rem;
  }
}

.project-links {
  display: flex;
  gap: 1rem;
}

.project-link {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--teal-accent);
  display: inline-flex;
  align-items: center;
  gap: 0.2rem;
}

.project-link:hover {
  filter: brightness(1.2);
}

/* Centered Contact layout without form (Responsive Stack) */
.contact-container-centered {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}

.contact-subtitle {
  color: var(--text-secondary);
  font-size: 0.98rem;
  margin-bottom: 2rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

@media (min-width: 768px) {
  .contact-subtitle {
    font-size: 1.08rem;
    margin-bottom: 3.5rem;
  }
}

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

@media (min-width: 768px) {
  .contact-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.25rem;
  }
}

.contact-method-card {
  display: flex;
  flex-direction: row; /* Horizontal layout on mobile contact cards */
  align-items: center;
  text-align: left;
  gap: 1rem;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 1.35rem;
  border-radius: 10px;
  transition: all 0.3s;
}

@media (min-width: 768px) {
  .contact-method-card {
    flex-direction: column; /* Centered column layout on desktop */
    text-align: center;
    padding: 2.5rem 1.6rem;
    gap: 1rem;
  }
}

.contact-method-card:hover {
  border-color: var(--teal-accent);
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.contact-method-icon {
  width: 56px; /* Enlarged mobile contact icons container */
  height: 56px;
  background: var(--primary-gradient);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.85rem; /* Enlarged mobile contact emoji size */
  color: #fff;
  flex-shrink: 0;
  box-shadow: 0 4px 8px var(--teal-glow);
}

@media (min-width: 768px) {
  .contact-method-icon {
    width: 68px; /* Enlarged desktop contact icons container */
    height: 68px;
    border-radius: 10px;
    font-size: 2.2rem; /* Enlarged desktop contact emoji size */
  }
}

.contact-method-label {
  font-size: 0.82rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.15rem;
}

.contact-method-value {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

@media (min-width: 768px) {
  .contact-method-value {
    font-size: 1.15rem;
  }
}

/* Footer */
.footer {
  border-top: 1px solid var(--border-color);
  padding: 2.5rem 0;
  margin-top: 4.5rem;
  text-align: center;
}

@media (min-width: 768px) {
  .footer {
    padding: 3rem 0;
    margin-top: 5.5rem;
  }
}

.footer-socials {
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.footer-social-link {
  width: 48px; /* Enlarged footer icons container */
  height: 48px;
  border-radius: 50%;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem; /* Enlarged footer emoji size */
  font-weight: 700;
  color: var(--text-secondary);
  transition: all 0.3s;
}

.footer-social-link:hover {
  background-color: var(--teal-accent);
  color: var(--bg-main);
  transform: scale(1.05);
}

.footer-copyright {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-copyright a:hover {
  color: var(--teal-accent);
}