/* ==========================================================================
   Freate Vietnam — Design Tokens & Core System
   ========================================================================== */

:root {
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Dark Theme Colors (Default) */
  --bg-primary: #07090e;
  --bg-secondary: #0d111a;
  --bg-card: rgba(255, 255, 255, 0.03);
  --bg-card-hover: rgba(255, 255, 255, 0.06);
  --border-card: rgba(255, 255, 255, 0.08);
  --border-card-hover: rgba(59, 130, 246, 0.4);

  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --text-dim: #6b7280;

  /* Accent Gradients & Colors */
  --accent-blue: #3b82f6;
  --accent-purple: #8b5cf6;
  --accent-cyan: #06b6d4;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;

  --nav-bg: rgba(7, 9, 14, 0.75);
  --shadow-glow: 0 0 25px rgba(59, 130, 246, 0.15);
  --backdrop-blur: blur(16px);
}

/* Light Theme Overrides */
[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.75);
  --bg-card-hover: rgba(255, 255, 255, 0.95);
  --border-card: rgba(0, 0, 0, 0.08);
  --border-card-hover: rgba(59, 130, 246, 0.4);

  --text-main: #0f172a;
  --text-muted: #475569;
  --text-dim: #64748b;

  --nav-bg: rgba(248, 250, 252, 0.85);
  --shadow-glow: 0 10px 25px rgba(0, 0, 0, 0.05);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
}

a {
  color: inherit;
  text-decoration: none;
}

/* Aurora Background Glow */
.bg-glow {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.glow-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.18;
  animation: floatOrb 18s infinite alternate ease-in-out;
}

.orb-1 { width: 500px; height: 500px; background: var(--accent-blue); top: -100px; left: -100px; }
.orb-2 { width: 600px; height: 600px; background: var(--accent-purple); bottom: -150px; right: -100px; animation-delay: -5s; }
.orb-3 { width: 400px; height: 400px; background: var(--accent-cyan); top: 40%; left: 50%; animation-delay: -10s; }

@keyframes floatOrb {
  0% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(60px, 40px) scale(1.1); }
  100% { transform: translate(-40px, 80px) scale(0.95); }
}

/* ==========================================================================
   Alert Toast Container & Cards
   ========================================================================== */

.alert-container {
  position: fixed;
  top: 80px;
  right: 20px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: 480px;
  width: calc(100% - 40px);
  pointer-events: none;
}

.toast-alert {
  pointer-events: auto;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 16px 20px;
  border-radius: 12px;
  background: var(--bg-card);
  backdrop-filter: var(--backdrop-blur);
  border: 1px solid var(--border-card);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
  animation: slideInToast 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes slideInToast {
  from { opacity: 0; transform: translateY(-20px) scale(0.95); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

.toast-alert.alert-error {
  border-color: rgba(244, 63, 94, 0.5);
  background: rgba(244, 63, 94, 0.12);
  color: #fca5a5;
}

.toast-alert.alert-warning {
  border-color: rgba(245, 158, 11, 0.5);
  background: rgba(245, 158, 11, 0.12);
  color: #fde68a;
}

.toast-alert.alert-success {
  border-color: rgba(16, 185, 129, 0.5);
  background: rgba(16, 185, 129, 0.12);
  color: #6ee7b7;
}

.toast-alert.alert-info {
  border-color: rgba(59, 130, 246, 0.5);
  background: rgba(59, 130, 246, 0.12);
  color: #93c5fd;
}

.toast-icon {
  flex-shrink: 0;
  margin-top: 2px;
}

.toast-content {
  flex-grow: 1;
  font-size: 0.92rem;
  line-height: 1.5;
}

.toast-close {
  background: none;
  border: none;
  color: currentColor;
  opacity: 0.7;
  cursor: pointer;
  padding: 2px;
  transition: opacity 0.2s;
}

.toast-close:hover { opacity: 1; }

/* ==========================================================================
   Navigation Bar
   ========================================================================== */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: var(--nav-bg);
  backdrop-filter: var(--backdrop-blur);
  border-bottom: 1px solid var(--border-card);
  transition: padding 0.3s ease;
  padding: 16px 0;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  font-size: 1.25rem;
}

.brand-text small {
  font-size: 0.65rem;
  color: var(--accent-blue);
  letter-spacing: 1px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 28px;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--accent-blue);
}

.theme-toggle {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  color: var(--text-main);
  padding: 8px;
  border-radius: 10px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.2s;
}

.theme-toggle:hover {
  border-color: var(--accent-blue);
}

[data-theme="dark"] .sun-icon { display: block; }
[data-theme="dark"] .moon-icon { display: none; }
[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background-color: var(--text-main);
  transition: 0.3s;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero {
  position: relative;
  z-index: 1;
  padding: 160px 0 100px;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: 30px;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.3);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-blue);
  margin-bottom: 24px;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--accent-blue);
  box-shadow: 0 0 10px var(--accent-blue);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { opacity: 0.4; transform: scale(0.9); }
  50% { opacity: 1; transform: scale(1.2); }
  100% { opacity: 0.4; transform: scale(0.9); }
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 900;
  letter-spacing: -1px;
  line-height: 1.15;
  margin-bottom: 20px;
}

.gradient-text {
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple), var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 720px;
  margin: 0 auto 16px;
}

.hero-founder {
  font-size: 0.95rem;
  color: var(--text-dim);
  margin-bottom: 36px;
}

.hero-founder a {
  color: var(--text-main);
  font-weight: 600;
  text-decoration: underline;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 28px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  cursor: pointer;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  color: #fff;
  border: none;
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  filter: brightness(1.1);
}

.btn-glass {
  background: var(--bg-card);
  backdrop-filter: var(--backdrop-blur);
  border: 1px solid var(--border-card);
  color: var(--text-main);
}

.btn-glass:hover {
  border-color: var(--accent-blue);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.85rem;
  border-radius: 8px;
}

.btn-secondary {
  background: rgba(139, 92, 246, 0.15);
  color: var(--accent-purple);
  border: 1px solid rgba(139, 92, 246, 0.3);
}

.btn-secondary:hover {
  background: rgba(139, 92, 246, 0.3);
}

.btn-ghost {
  background: transparent;
  border: 1px solid var(--border-card);
  color: var(--text-muted);
}

.btn-ghost:hover {
  color: var(--text-main);
  border-color: var(--text-muted);
}

/* ==========================================================================
   Section Headers & Common Layouts
   ========================================================================== */

section {
  position: relative;
  z-index: 1;
  padding: 90px 0;
}

.section-header {
  text-align: center;
  max-width: 650px;
  margin: 0 auto 60px;
}

.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--accent-blue);
  margin-bottom: 12px;
}

.section-header h2 {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.section-header p {
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* About Grid */
.about-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.about-card {
  background: var(--bg-card);
  backdrop-filter: var(--backdrop-blur);
  border: 1px solid var(--border-card);
  padding: 32px;
  border-radius: 20px;
  transition: transform 0.3s, border-color 0.3s;
}

.about-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-card-hover);
}

.card-icon {
  width: 54px;
  height: 54px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.icon-blue { background: rgba(59, 130, 246, 0.15); color: var(--accent-blue); }
.icon-purple { background: rgba(139, 92, 246, 0.15); color: var(--accent-purple); }
.icon-cyan { background: rgba(6, 182, 212, 0.15); color: var(--accent-cyan); }
.icon-diary { background: rgba(244, 63, 94, 0.15); color: var(--accent-rose); }
.icon-drop { background: rgba(16, 185, 129, 0.15); color: var(--accent-emerald); }
.icon-oj { background: rgba(245, 158, 11, 0.15); color: var(--accent-amber); }
.icon-wiki { background: rgba(139, 92, 246, 0.15); color: var(--accent-purple); }
.icon-docs { background: rgba(59, 130, 246, 0.15); color: var(--accent-blue); }

.about-card h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
}

.about-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Projects Grid */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 28px;
}

.project-card {
  background: var(--bg-card);
  backdrop-filter: var(--backdrop-blur);
  border: 1px solid var(--border-card);
  padding: 32px;
  border-radius: 24px;
  display: flex;
  flex-direction: column;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.project-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-card-hover);
  box-shadow: var(--shadow-glow);
}

.project-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 20px;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  justify-content: flex-end;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  padding: 4px 8px;
  border-radius: 6px;
  font-weight: 500;
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-muted);
}

.tag-rust { color: #f97316; background: rgba(249, 115, 22, 0.12); }
.tag-python { color: #38bdf8; background: rgba(56, 189, 248, 0.12); }
.tag-docker { color: #60a5fa; background: rgba(96, 165, 250, 0.12); }
.tag-security { color: #f43f5e; background: rgba(244, 63, 94, 0.12); }
.tag-actix { color: #a855f7; background: rgba(168, 85, 247, 0.12); }
.tag-sqlite { color: #34d399; background: rgba(52, 211, 153, 0.12); }
.tag-gui { color: #e879f9; background: rgba(232, 121, 249, 0.12); }
.tag-feature { color: #fbbf24; background: rgba(251, 191, 36, 0.12); }
.tag-docs { color: #3b82f6; background: rgba(59, 130, 246, 0.12); }
.tag-html { color: #ec4899; background: rgba(236, 72, 153, 0.12); }

.project-card h3 {
  font-size: 1.4rem;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.dual-badge {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  background: rgba(59, 130, 246, 0.15);
  color: var(--accent-blue);
  padding: 2px 6px;
  border-radius: 4px;
}

.project-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 16px;
  flex-grow: 1;
}

.project-features {
  list-style: none;
  margin-bottom: 24px;
  border-top: 1px solid var(--border-card);
  padding-top: 16px;
}

.project-features li {
  font-size: 0.88rem;
  color: var(--text-dim);
  margin-bottom: 8px;
  position: relative;
  padding-left: 18px;
}

.project-features li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--accent-emerald);
  font-weight: bold;
}

.project-links {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: auto;
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  padding: 24px;
  border-radius: 16px;
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.fi-blue { background: rgba(59, 130, 246, 0.15); color: var(--accent-blue); }
.fi-purple { background: rgba(139, 92, 246, 0.15); color: var(--accent-purple); }
.fi-cyan { background: rgba(6, 182, 212, 0.15); color: var(--accent-cyan); }
.fi-emerald { background: rgba(16, 185, 129, 0.15); color: var(--accent-emerald); }

.feature-card h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* Stats Section */
.stats {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-card);
  border-bottom: 1px solid var(--border-card);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 30px;
  text-align: center;
}

.stat-number {
  display: block;
  font-size: 3rem;
  font-weight: 900;
  font-family: var(--font-mono);
  color: var(--text-main);
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.stat-label {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 500;
}

/* Contact Grid */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.contact-card {
  background: var(--bg-card);
  backdrop-filter: var(--backdrop-blur);
  border: 1px solid var(--border-card);
  padding: 30px;
  border-radius: 20px;
  text-align: center;
  transition: transform 0.3s, border-color 0.3s;
}

.contact-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-blue);
}

.contact-icon {
  margin-bottom: 12px;
  color: var(--accent-blue);
}

.contact-card h3 {
  font-size: 1.2rem;
  margin-bottom: 4px;
}

.contact-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Footer */
.footer {
  padding: 60px 0 40px;
  border-top: 1px solid var(--border-card);
  text-align: center;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.2rem;
  margin-bottom: 8px;
}

.footer-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 20px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 24px;
}

.footer-links a {
  color: var(--text-dim);
  font-size: 0.9rem;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: var(--accent-blue);
}

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

/* Scroll Reveal Initial State */
[data-aos] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-aos].aos-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive Breakpoints */
@media (max-width: 768px) {
  .hero-title { font-size: 2.4rem; }
  .nav-links {
    position: fixed;
    top: 70px;
    left: 0;
    width: 100%;
    background: var(--bg-primary);
    flex-direction: column;
    padding: 30px;
    gap: 20px;
    border-bottom: 1px solid var(--border-card);
    transform: translateY(-150%);
    transition: transform 0.3s ease;
  }
  .nav-links.open { transform: translateY(0); }
  .nav-toggle { display: flex; }
}