/* ===========================
   TEACHMEMATE GLOBAL STYLES
   Sleek Black Theme
   =========================== */

:root {
  /* Primary Colors */
  --primary-black: #0a0e27;
  --secondary-black: #141829;
  --tertiary-black: #1a1f3a;
  --accent-black: #252d47;
  
  /* Accent Colors */
  --neon-cyan: #00d4ff;
  --neon-purple: #b74bff;
  --neon-pink: #ff006e;
  --neon-green: #39ff14;
  
  /* Neutral Colors */
  --light-gray: #e0e0e0;
  --medium-gray: #a0a0a0;
  --dark-gray: #4a4a4a;
  
  /* Shadows & Effects */
  --shadow-sm: 0 2px 8px rgba(0, 212, 255, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 212, 255, 0.15);
  --shadow-lg: 0 8px 32px rgba(0, 212, 255, 0.2);
  --glow-cyan: 0 0 20px rgba(0, 212, 255, 0.4);
  --glow-purple: 0 0 20px rgba(183, 75, 255, 0.4);
  
  /* Typography */
  --font-primary: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --font-mono: 'Courier New', monospace;
  
  /* Transitions */
  --transition-fast: 0.2s ease-in-out;
  --transition-smooth: 0.4s ease-in-out;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  font-family: var(--font-primary);
  background: linear-gradient(135deg, var(--primary-black) 0%, var(--secondary-black) 100%);
  color: var(--light-gray);
  line-height: 1.6;
}

/* ===========================
   TYPOGRAPHY
   =========================== */

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: 0.5px;
}

h1 {
  font-size: 2.5rem;
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: 2rem;
  color: var(--neon-cyan);
}

h3 {
  font-size: 1.5rem;
  color: var(--light-gray);
}

h4 {
  font-size: 1.25rem;
  color: var(--medium-gray);
}

p {
  color: var(--medium-gray);
  margin-bottom: 1rem;
}

a {
  color: var(--neon-cyan);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--neon-pink);
  text-shadow: var(--glow-cyan);
}

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

.btn {
  padding: 12px 28px;
  border: 2px solid transparent;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-transform: uppercase;
  letter-spacing: 1px;
  position: relative;
  overflow: hidden;
  font-family: var(--font-primary);
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: rgba(0, 212, 255, 0.1);
  transition: left var(--transition-fast);
  z-index: -1;
}

.btn:hover::before {
  left: 100%;
}

/* Primary Button - Cyan */
.btn-primary {
  background: linear-gradient(135deg, var(--neon-cyan), #00a8cc);
  color: var(--primary-black);
  border-color: var(--neon-cyan);
  box-shadow: var(--shadow-md), var(--glow-cyan);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), var(--glow-cyan);
}

/* Secondary Button - Purple */
.btn-secondary {
  background: linear-gradient(135deg, var(--neon-purple), #9c2aff);
  color: var(--primary-black);
  border-color: var(--neon-purple);
  box-shadow: var(--shadow-md), var(--glow-purple);
}

.btn-secondary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), var(--glow-purple);
}

/* Outlined Button */
.btn-outline {
  background: transparent;
  color: var(--neon-cyan);
  border-color: var(--neon-cyan);
  box-shadow: 0 0 10px rgba(0, 212, 255, 0.2);
}

.btn-outline:hover {
  background: rgba(0, 212, 255, 0.1);
  box-shadow: var(--glow-cyan);
}

/* Ghost Button */
.btn-ghost {
  background: transparent;
  color: var(--light-gray);
  border-color: var(--dark-gray);
}

.btn-ghost:hover {
  color: var(--neon-cyan);
  border-color: var(--neon-cyan);
}

/* ===========================
   FORM ELEMENTS
   =========================== */

.form-group {
  margin-bottom: 1.5rem;
  display: flex;
  flex-direction: column;
}

label {
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: var(--light-gray);
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

input, textarea, select {
  padding: 12px 16px;
  background: var(--accent-black);
  border: 2px solid var(--tertiary-black);
  border-radius: 6px;
  color: var(--light-gray);
  font-family: var(--font-primary);
  font-size: 1rem;
  transition: all var(--transition-fast);
}

input::placeholder, textarea::placeholder {
  color: var(--dark-gray);
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--neon-cyan);
  background: rgba(0, 212, 255, 0.05);
  box-shadow: 0 0 10px rgba(0, 212, 255, 0.3);
}

textarea {
  resize: vertical;
  min-height: 120px;
}

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

.card {
  background: var(--tertiary-black);
  border: 1px solid var(--accent-black);
  border-radius: 8px;
  padding: 24px;
  transition: all var(--transition-smooth);
  box-shadow: var(--shadow-sm);
}

.card:hover {
  border-color: var(--neon-cyan);
  box-shadow: var(--shadow-md), var(--glow-cyan);
  transform: translateY(-4px);
}

.card-header {
  border-bottom: 2px solid var(--accent-black);
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
}

.card-title {
  font-size: 1.25rem;
  color: var(--neon-cyan);
  margin: 0;
}

.card-footer {
  border-top: 1px solid var(--accent-black);
  margin-top: 1.5rem;
  padding-top: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* ===========================
   NAVIGATION
   =========================== */

nav {
  background: rgba(10, 14, 39, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--accent-black);
  padding: 1rem 0;
  box-shadow: var(--shadow-md);
}

.navbar {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.navbar-brand {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-transform: uppercase;
  letter-spacing: 2px;
}

.nav-menu {
  list-style: none;
  display: flex;
  gap: 2rem;
}

.nav-item a {
  color: var(--light-gray);
  transition: all var(--transition-fast);
  position: relative;
  padding-bottom: 4px;
}

.nav-item a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--neon-cyan);
  transition: width var(--transition-fast);
}

.nav-item a:hover {
  color: var(--neon-cyan);
}

.nav-item a:hover::after {
  width: 100%;
}

/* ===========================
   CONTAINERS & LAYOUT
   =========================== */

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
}

.hero {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  text-align: center;
  padding: 2rem;
  background: linear-gradient(135deg, rgba(0, 212, 255, 0.05), rgba(183, 75, 255, 0.05));
}

.hero-content {
  max-width: 800px;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--neon-cyan);
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 2px;
}

.grid {
  display: grid;
  gap: 2rem;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

/* ===========================
   USER PROFILE & AVATAR
   =========================== */

.avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--neon-cyan), var(--neon-purple));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary-black);
  font-weight: 700;
  font-size: 1.25rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: var(--glow-cyan);
}

.avatar:hover {
  transform: scale(1.1);
}

.profile-card {
  text-align: center;
}

.profile-card .avatar {
  width: 100px;
  height: 100px;
  font-size: 2rem;
  margin: 0 auto 1rem;
}

/* ===========================
   BADGES & TAGS
   =========================== */

.badge {
  display: inline-block;
  padding: 6px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge-primary {
  background: rgba(0, 212, 255, 0.2);
  color: var(--neon-cyan);
  border: 1px solid var(--neon-cyan);
}

.badge-success {
  background: rgba(57, 255, 20, 0.2);
  color: var(--neon-green);
  border: 1px solid var(--neon-green);
}

.badge-danger {
  background: rgba(255, 0, 110, 0.2);
  color: var(--neon-pink);
  border: 1px solid var(--neon-pink);
}

/* ===========================
   MODALS & OVERLAYS
   =========================== */

.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(5px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal {
  background: var(--secondary-black);
  border: 2px solid var(--accent-black);
  border-radius: 12px;
  padding: 2rem;
  max-width: 500px;
  width: 90%;
  box-shadow: 0 0 30px rgba(0, 212, 255, 0.3);
}

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

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }

.flex {
  display: flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.flex-between {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.flex-column {
  display: flex;
  flex-direction: column;
}

.opacity-50 { opacity: 0.5; }
.opacity-75 { opacity: 0.75; }

.hidden { display: none; }

/* ===========================
   RESPONSIVE DESIGN
   =========================== */

@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  
  .navbar {
    flex-direction: column;
    gap: 1rem;
  }
  
  .nav-menu {
    flex-direction: column;
    gap: 1rem;
  }
  
  .container {
    padding: 0 1rem;
  }
  
  .hero {
    min-height: 80vh;
  }
  
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
}