@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;500;600;700;800;900&display=swap');

:root {
  --green-100: #e8f5e9;
  --green-200: #c8e6c9;
  --green-300: #a5d6a7;
  --green-400: #66bb6a;
  --green-500: #4caf50;
  --green-600: #43a047;
  --green-700: #388e3c;
  --green-800: #2e7d32;
  --green-900: #1b5e20;
  --leaf: #58cc02;
  --leaf-dark: #46a302;
  --leaf-light: #89e219;
  --leaf-bg: #f0fce8;
  --sky: #1cb0f6;
  --sky-dark: #0095d9;
  --gold: #ffc800;
  --gold-dark: #e5a800;
  --fire: #ff4b4b;
  --fire-dark: #ea2b2b;
  --purple: #ce82ff;
  --bg-primary: #f7f7f7;
  --bg-white: #ffffff;
  --bg-green-soft: #f0fce8;
  --bg-sidebar: #ffffff;
  --text-primary: #3c3c3c;
  --text-secondary: #777777;
  --text-muted: #afafaf;
  --border: #e5e5e5;
  --border-active: #58cc02;
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.12);
  --shadow-btn: 0 4px 0;
  --radius: 16px;
  --radius-lg: 20px;
  --radius-xl: 24px;
  --transition: all 0.2s ease;
}

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

body {
  font-family: 'Nunito', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
}

::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--green-300); border-radius: 4px; }

/* ===== LANDING PAGE ===== */
.landing-page { min-height: 100vh; background: linear-gradient(180deg, #f0fce8 0%, #ffffff 100%); }

.landing-nav {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 48px; background: white; border-bottom: 2px solid var(--border);
  position: sticky; top: 0; z-index: 100;
}

.landing-logo { display: flex; align-items: center; gap: 12px; }
.landing-logo img { width: 48px; height: 48px; }
.landing-logo h1 { font-size: 24px; font-weight: 900; color: var(--green-800); }

.landing-nav-btns { display: flex; gap: 12px; }

.landing-hero {
  display: flex; align-items: center; justify-content: center;
  gap: 60px; padding: 80px 48px; max-width: 1200px; margin: 0 auto;
}

.hero-left { flex: 1; max-width: 500px; }
.hero-left h2 { font-size: 42px; font-weight: 900; color: var(--green-900); line-height: 1.2; margin-bottom: 16px; }
.hero-left p { font-size: 18px; color: var(--text-secondary); line-height: 1.6; margin-bottom: 32px; }

.hero-right { flex: 1; display: flex; justify-content: center; }
.hero-mascot { width: 350px; height: 350px; animation: float 3s ease-in-out infinite; }

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-20px); }
}

.landing-features {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 24px; padding: 60px 48px; max-width: 1200px; margin: 0 auto;
}

.feature-card {
  background: white; border-radius: var(--radius-lg); padding: 32px;
  border: 2px solid var(--border); text-align: center;
  transition: var(--transition);
}

.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--leaf); }
.feature-icon { font-size: 48px; margin-bottom: 16px; }
.feature-card h3 { font-size: 18px; font-weight: 800; margin-bottom: 8px; color: var(--green-800); }
.feature-card p { color: var(--text-secondary); font-size: 14px; line-height: 1.5; }

.landing-companies {
  padding: 60px 48px; max-width: 1200px; margin: 0 auto; text-align: center;
}

.landing-companies h2 { font-size: 32px; font-weight: 900; color: var(--green-900); margin-bottom: 32px; }

.company-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px; text-align: left;
}

.company-card {
  background: white; border: 2px solid var(--border); border-radius: var(--radius-lg);
  padding: 24px; transition: var(--transition);
}

.company-card:hover { border-color: var(--leaf); box-shadow: var(--shadow); }
.company-card h4 { font-size: 16px; font-weight: 800; margin-bottom: 4px; }
.company-salary { color: var(--leaf-dark); font-weight: 800; font-size: 15px; }
.company-rating { color: var(--gold); font-size: 14px; margin: 4px 0; }
.company-review { font-size: 13px; color: var(--text-secondary); line-height: 1.5; margin-top: 8px; }
.company-tags { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 8px; }
.company-tag {
  padding: 2px 10px; border-radius: 12px; font-size: 11px; font-weight: 700;
  background: var(--leaf-bg); color: var(--leaf-dark);
}
/* ===== ICONS ===== */
.img-icon { width: 24px; height: 24px; object-fit: contain; }
.stat-card .img-icon { width: 44px; height: 44px; margin-bottom: 8px; }

/* ===== AUTH SCREEN ===== */
.auth-screen {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(180deg, #f0fce8 0%, #e8f5e9 100%);
}

.auth-card {
  background: white; border: 2px solid var(--border); border-radius: var(--radius-xl);
  padding: 48px; width: 100%; max-width: 420px; box-shadow: var(--shadow-lg);
}

.auth-logo { text-align: center; margin-bottom: 24px; }
.auth-logo img { width: 100px; height: 100px; margin-bottom: 12px; }
.auth-logo h1 { font-size: 28px; font-weight: 900; color: var(--green-800); }
.auth-logo p { color: var(--text-secondary); margin-top: 4px; font-size: 14px; }

.form-group { margin-bottom: 16px; }
.form-group label {
  display: block; font-size: 13px; font-weight: 800; color: var(--text-secondary);
  margin-bottom: 6px; text-transform: uppercase;
}

.form-group input, .form-group textarea, .form-group select {
  width: 100%; padding: 14px 16px; background: var(--bg-primary);
  border: 2px solid var(--border); border-radius: var(--radius);
  color: var(--text-primary); font-size: 16px; font-family: inherit;
  transition: var(--transition); outline: none;
}

.form-group input:focus, .form-group textarea:focus {
  border-color: var(--leaf); box-shadow: 0 0 0 3px rgba(88, 204, 2, 0.2);
}

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

/* ===== BUTTONS (Duolingo-style 3D) ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 13px 24px; border: none; border-bottom: 4px solid;
  border-radius: var(--radius); font-size: 15px; font-weight: 800;
  font-family: inherit; cursor: pointer; transition: var(--transition);
  text-decoration: none; text-transform: uppercase; letter-spacing: 0.5px;
}

.btn:active { transform: translateY(2px); border-bottom-width: 2px; }

.btn-primary {
  background: var(--leaf); color: white; border-bottom-color: var(--leaf-dark);
}
.btn-primary:hover { background: var(--leaf-dark); }

.btn-secondary {
  background: white; color: var(--text-primary);
  border: 2px solid var(--border); border-bottom: 4px solid var(--border);
}
.btn-secondary:hover { background: var(--bg-primary); }

.btn-sky { background: var(--sky); color: white; border-bottom-color: var(--sky-dark); }
.btn-gold { background: var(--gold); color: #3c3c3c; border-bottom-color: var(--gold-dark); }
.btn-fire { background: var(--fire); color: white; border-bottom-color: var(--fire-dark); }
.btn-sm { padding: 8px 16px; font-size: 12px; }
.btn-lg { padding: 16px 32px; font-size: 17px; }
.btn-block { width: 100%; }
.btn-icon { width: 44px; height: 44px; padding: 0; border-radius: 50%; }

.auth-toggle {
  text-align: center; margin-top: 20px; color: var(--text-muted); font-size: 14px;
}
.auth-toggle a { color: var(--sky); cursor: pointer; text-decoration: none; font-weight: 800; }

/* ===== LAYOUT ===== */
.app-layout { display: flex; min-height: 100vh; }

.sidebar {
  width: 260px; background: var(--bg-sidebar); border-right: 2px solid var(--border);
  display: flex; flex-direction: column; position: fixed; top: 0; left: 0; bottom: 0; z-index: 100;
  transition: var(--transition);
}

.sidebar-header {
  padding: 20px 20px; border-bottom: 2px solid var(--border);
  display: flex; align-items: center; gap: 12px;
}
.sidebar-header img { width: 44px; height: 44px; }
.sidebar-header h2 { font-size: 18px; font-weight: 900; color: var(--green-800); }

.sidebar-nav { flex: 1; padding: 12px 8px; overflow-y: auto; }
.nav-section { margin-bottom: 16px; }
.nav-section-title {
  font-size: 11px; font-weight: 800; color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 1px; padding: 0 16px; margin-bottom: 4px;
}

.nav-item {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px; border-radius: var(--radius);
  color: var(--text-secondary); cursor: pointer; transition: var(--transition);
  font-size: 15px; font-weight: 700; margin-bottom: 2px; border: 2px solid transparent;
}
.nav-item:hover { background: var(--leaf-bg); color: var(--green-800); }
.nav-item.active {
  background: var(--leaf-bg); color: var(--leaf-dark);
  border-color: var(--leaf);
}
.nav-item .nav-icon { font-size: 20px; width: 28px; text-align: center; }
.nav-item .nav-badge {
  margin-left: auto; background: var(--fire); color: white;
  font-size: 11px; font-weight: 800; padding: 2px 8px; border-radius: 10px;
}

.sidebar-footer { padding: 12px; border-top: 2px solid var(--border); }
.user-info {
  display: flex; align-items: center; gap: 12px;
  padding: 12px; border-radius: var(--radius); background: var(--leaf-bg);
}

.user-avatar {
  width: 40px; height: 40px; border-radius: 50%;
  background: var(--leaf); display: flex; align-items: center; justify-content: center;
  font-weight: 900; font-size: 16px; color: white;
}
.user-details h4 { font-size: 14px; font-weight: 800; color: var(--green-800); }
.user-details p { font-size: 12px; color: var(--text-secondary); }

.main-content { flex: 1; margin-left: 260px; padding: 32px; min-height: 100vh; }

.page-header { margin-bottom: 28px; }
.page-header h1 { font-size: 28px; font-weight: 900; color: var(--green-900); }
.page-header p { color: var(--text-secondary); font-size: 15px; margin-top: 4px; }

/* ===== CARDS ===== */
.card {
  background: white; border: 2px solid var(--border); border-radius: var(--radius-lg);
  padding: 24px; margin-bottom: 20px; transition: var(--transition);
}
.card:hover { border-color: var(--green-300); }
.card-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
.card-title { font-size: 18px; font-weight: 800; color: var(--green-800); }
.card-subtitle { font-size: 13px; color: var(--text-muted); margin-top: 2px; }

/* ===== STATS GRID ===== */
.stats-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px; margin-bottom: 28px;
}

.stat-card {
  background: white; border: 2px solid var(--border); border-radius: var(--radius-lg);
  padding: 24px; transition: var(--transition); text-align: center;
}
.stat-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--leaf); }
.stat-icon { font-size: 36px; margin-bottom: 8px; }
.stat-value { font-size: 32px; font-weight: 900; color: var(--green-800); margin-bottom: 2px; }
.stat-label { font-size: 13px; color: var(--text-secondary); font-weight: 700; }

/* ===== VOCABULARY ===== */
.vocab-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 16px; }

.vocab-card {
  background: white; border: 2px solid var(--border); border-radius: var(--radius-lg);
  padding: 20px; cursor: pointer; transition: var(--transition); overflow: hidden;
}
.vocab-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--leaf); }
.vocab-card.learned { border-left: 5px solid var(--leaf); }
.vocab-term { font-size: 20px; font-weight: 900; color: var(--green-800); margin-bottom: 2px; }
.vocab-type { color: var(--sky); font-size: 13px; font-weight: 800; margin-bottom: 6px; }
.vocab-def { color: var(--text-secondary); font-size: 14px; line-height: 1.5; margin-bottom: 8px; }
.vocab-examples { border-top: 2px solid var(--border); padding-top: 12px; display: none; }
.vocab-card.expanded .vocab-examples { display: block; }

.vocab-example {
  font-size: 13px; color: var(--text-secondary); padding: 6px 0 6px 16px;
  border-left: 3px solid var(--leaf); margin-bottom: 6px; line-height: 1.5;
}
.vocab-actions { display: flex; gap: 8px; margin-top: 12px; }

.badge {
  display: inline-block; padding: 4px 12px; border-radius: 20px;
  font-size: 12px; font-weight: 800;
}
.badge-algo { background: rgba(88, 204, 2, 0.15); color: var(--leaf-dark); }
.badge-data { background: rgba(28, 176, 246, 0.15); color: var(--sky-dark); }
.badge-hw { background: rgba(255, 200, 0, 0.15); color: var(--gold-dark); }

/* ===== PRONUNCIATION ===== */
.pronunciation-area {
  background: var(--leaf-bg); border: 3px dashed var(--green-300);
  border-radius: var(--radius-lg); padding: 40px; text-align: center; margin: 20px 0;
  transition: var(--transition);
}
.pronunciation-area.recording { border-color: var(--fire); background: #fff5f5; animation: pulse 1.5s infinite; }

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(255, 75, 75, 0.3); }
  50% { box-shadow: 0 0 0 15px rgba(255, 75, 75, 0); }
}

.record-btn {
  width: 80px; height: 80px; border-radius: 50%; border: none;
  background: var(--leaf); color: white; font-size: 32px; cursor: pointer;
  transition: var(--transition); border-bottom: 5px solid var(--leaf-dark);
}
.record-btn:hover { transform: scale(1.05); }
.record-btn:active { transform: translateY(3px); border-bottom-width: 2px; }
.record-btn.recording { background: var(--fire); border-bottom-color: var(--fire-dark); animation: pulse 1.5s infinite; }

.pronunciation-result {
  margin-top: 20px; padding: 20px; border-radius: var(--radius);
  background: white; border: 2px solid var(--border);
}

.score-circle {
  width: 80px; height: 80px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; font-weight: 900; margin: 0 auto 12px; border: 5px solid;
}
.score-high { border-color: var(--leaf); color: var(--leaf-dark); background: var(--leaf-bg); }
.score-mid { border-color: var(--gold); color: var(--gold-dark); background: #fffde8; }
.score-low { border-color: var(--fire); color: var(--fire-dark); background: #fff5f5; }

/* ===== READING ===== */
.passage-content {
  line-height: 1.9; font-size: 16px; color: var(--text-primary); padding: 24px;
  background: var(--leaf-bg); border-radius: var(--radius); border-left: 5px solid var(--leaf);
  margin-bottom: 24px; white-space: pre-line;
}

/* ===== QUIZ ===== */
.quiz-question {
  margin-bottom: 20px; padding: 20px; background: white;
  border-radius: var(--radius); border: 2px solid var(--border);
}
.quiz-question h4 { font-size: 15px; margin-bottom: 12px; font-weight: 800; }

.quiz-options { display: flex; flex-direction: column; gap: 8px; }

.quiz-option {
  display: flex; align-items: center; gap: 12px; padding: 14px 16px;
  background: white; border: 2px solid var(--border); border-bottom: 4px solid var(--border);
  border-radius: var(--radius); cursor: pointer; transition: var(--transition);
  font-size: 15px; font-weight: 700;
}
.quiz-option:hover { border-color: var(--sky); background: #f0f8ff; }
.quiz-option.selected { border-color: var(--sky); background: #e3f2fd; }
.quiz-option.correct { border-color: var(--leaf); background: var(--leaf-bg); border-bottom-color: var(--leaf-dark); }
.quiz-option.incorrect { border-color: var(--fire); background: #fff5f5; border-bottom-color: var(--fire-dark); }
.quiz-option input[type="radio"] { display: none; }

/* ===== LISTENING ===== */
.dialogue-text {
  background: var(--leaf-bg); border-radius: var(--radius); padding: 20px;
  margin-bottom: 16px; line-height: 1.9; font-size: 15px; white-space: pre-line;
  border: 2px solid var(--green-200);
}

.tts-controls { display: flex; gap: 8px; align-items: center; margin-bottom: 16px; flex-wrap: wrap; }
.speed-selector { display: flex; gap: 4px; }

.speed-btn {
  padding: 6px 14px; border: 2px solid var(--border); background: white;
  color: var(--text-secondary); border-radius: var(--radius); cursor: pointer;
  font-size: 13px; font-weight: 800; transition: var(--transition);
}
.speed-btn.active { background: var(--leaf); color: white; border-color: var(--leaf-dark); }

/* ===== VIDEO ===== */
.video-container {
  position: relative; width: 100%; padding-top: 56.25%;
  border-radius: var(--radius); overflow: hidden; margin-bottom: 16px;
  border: 2px solid var(--border);
}
.video-container iframe { position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: none; }

/* ===== WRITING ===== */
.writing-area {
  width: 100%; min-height: 200px; padding: 20px; background: white;
  border: 2px solid var(--border); border-radius: var(--radius);
  color: var(--text-primary); font-family: inherit; font-size: 16px; line-height: 1.8; resize: vertical;
}
.writing-area:focus { outline: none; border-color: var(--leaf); box-shadow: 0 0 0 3px rgba(88,204,2,0.2); }
.word-counter { text-align: right; font-size: 13px; color: var(--text-muted); font-weight: 700; margin-top: 8px; }

.sample-answer {
  background: var(--leaf-bg); border: 2px solid var(--green-200); border-radius: var(--radius);
  padding: 20px; margin-top: 16px; line-height: 1.8;
}
.sample-answer h4 { color: var(--leaf-dark); margin-bottom: 8px; font-weight: 800; }

/* ===== PROGRESS BAR ===== */
.progress-bar-container { background: var(--border); border-radius: 10px; height: 12px; overflow: hidden; margin: 8px 0; }
.progress-bar-fill { height: 100%; background: var(--leaf); border-radius: 10px; transition: width 0.5s ease; }

/* ===== DAY SELECTOR ===== */
.day-selector { display: flex; gap: 8px; margin-bottom: 24px; flex-wrap: wrap; align-items: center; }

.day-btn {
  width: 44px; height: 44px; border-radius: 50%;
  border: 2px solid var(--border); background: white; color: var(--text-secondary);
  font-weight: 800; cursor: pointer; transition: var(--transition); font-size: 14px;
  border-bottom: 4px solid var(--border);
}
.day-btn.active, .day-btn:hover {
  background: var(--leaf); color: white; border-color: var(--leaf-dark);
  border-bottom-color: var(--leaf-dark);
}

/* ===== TABS ===== */
.tabs {
  display: flex; gap: 4px; margin-bottom: 24px; background: var(--bg-primary);
  padding: 4px; border-radius: var(--radius); border: 2px solid var(--border); flex-wrap: wrap;
}

.tab {
  padding: 10px 20px; border: none; background: transparent; color: var(--text-secondary);
  font-size: 14px; font-weight: 800; font-family: inherit; cursor: pointer;
  border-radius: 12px; transition: var(--transition);
}
.tab.active { background: var(--leaf); color: white; }

/* ===== FLASHCARD ===== */
.flashcard { perspective: 1000px; width: 100%; max-width: 500px; height: 300px; margin: 0 auto 24px; cursor: pointer; }
.flashcard-inner {
  position: relative; width: 100%; height: 100%;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1); transform-style: preserve-3d;
}
.flashcard.flipped .flashcard-inner { transform: rotateY(180deg); }

.flashcard-front, .flashcard-back {
  position: absolute; width: 100%; height: 100%; backface-visibility: hidden;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  padding: 32px; border-radius: var(--radius-xl); border: 3px solid; text-align: center;
}
.flashcard-front {
  background: var(--leaf); border-color: var(--leaf-dark); color: white;
  border-bottom: 6px solid var(--leaf-dark);
}
.flashcard-front h2 { font-size: 28px; margin-bottom: 8px; }
.flashcard-back {
  background: white; border-color: var(--border); transform: rotateY(180deg);
  border-bottom: 6px solid var(--border);
}
.flashcard-back h3 { color: var(--green-800); margin-bottom: 12px; font-size: 20px; }
.flashcard-back p { color: var(--text-secondary); line-height: 1.6; }

/* ===== TOAST ===== */
.toast-container { position: fixed; top: 24px; right: 24px; z-index: 9999; display: flex; flex-direction: column; gap: 8px; }

.toast {
  padding: 14px 20px; border-radius: var(--radius); font-size: 14px; font-weight: 800;
  box-shadow: var(--shadow-lg); animation: slideIn 0.3s ease;
  display: flex; align-items: center; gap: 10px; min-width: 300px;
  border-bottom: 4px solid;
}
.toast-success { background: var(--leaf); color: white; border-bottom-color: var(--leaf-dark); }
.toast-error { background: var(--fire); color: white; border-bottom-color: var(--fire-dark); }
.toast-info { background: var(--sky); color: white; border-bottom-color: var(--sky-dark); }

@keyframes slideIn { from { transform: translateX(100%); opacity: 0; } to { transform: translateX(0); opacity: 1; } }

/* ===== INTERVIEW ===== */
.interview-scenario {
  background: white; border-radius: var(--radius-lg); padding: 24px;
  margin-bottom: 16px; border: 2px solid var(--border); border-left: 5px solid var(--gold);
}
.interview-scenario h4 { color: var(--green-800); margin-bottom: 8px; font-weight: 800; }

/* ===== MOBILE ===== */
/* ===== RESPONSIVE DESIGN FOR TABLETS & LAPTOPS (max-width: 1024px) ===== */
@media (max-width: 1024px) {
  /* Sidebar handling for iPads in portrait */
  .sidebar { width: 220px; }
  .main-content { margin-left: 220px; padding: 24px; }
  
  /* Landing page adjustments */
  .landing-hero { padding: 60px 32px; gap: 40px; }
  .hero-left h2 { font-size: 36px; }
  .hero-mascot { width: 280px; height: 280px; }
  .landing-features { padding: 40px 32px; grid-template-columns: repeat(2, 1fr); }
  .landing-companies { padding: 40px 32px; }
  
  /* Stats Grid */
  .stats-grid { grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }
  
  /* Vocab cards */
  .vocab-grid { grid-template-columns: repeat(2, 1fr); }
}

/* ===== RESPONSIVE DESIGN FOR MOBILE & SMALL TABLETS (max-width: 768px) ===== */
@media (max-width: 768px) {
  /* App Layout & navigation */
  .menu-toggle { display: flex; align-items: center; justify-content: center; }
  
  .sidebar { 
    width: 280px; 
    transform: translateX(-100%); 
    box-shadow: none;
  }
  .sidebar.open { 
    transform: translateX(0); 
    box-shadow: 4px 0 16px rgba(0,0,0,0.15); 
  }
  
  /* Overlay when sidebar is open on mobile */
  .sidebar-overlay {
    display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5); z-index: 90;
  }
  .sidebar-overlay.active { display: block; }
  
  .main-content { 
    margin-left: 0; 
    padding: 72px 16px 32px; 
  }

  /* Page Headers */
  .page-header h1 { font-size: 24px; }
  .page-header { margin-bottom: 20px; }

  /* Auth Screens */
  .auth-card { 
    margin: 16px; 
    padding: 32px 20px; 
    width: calc(100% - 32px);
  }
  .auth-logo h1 { font-size: 24px; }
  
  /* Buttons */
  .btn-lg { padding: 12px 24px; font-size: 15px; }
  
  /* Landing Page */
  .landing-hero { 
    flex-direction: column; 
    text-align: center;
    padding: 40px 20px; 
    gap: 32px; 
  }
  .hero-left h2 { font-size: 32px; margin-bottom: 12px; }
  .hero-left p { font-size: 16px; margin-bottom: 24px; }
  .hero-mascot { width: 220px; height: 220px; }
  
  .landing-nav { 
    padding: 12px 16px; 
    flex-wrap: wrap;
    gap: 12px;
  }
  
  .landing-features { padding: 40px 16px; gap: 16px; }
  .landing-companies { padding: 40px 16px; }
  .company-grid { gap: 16px; }

  /* Grids & Cards */
  .stats-grid { gap: 12px; margin-bottom: 20px; }
  .card { padding: 16px; }
  
  /* Elements */
  .vocab-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .category-filter { gap: 6px; }
  .filter-btn { padding: 6px 14px; font-size: 12px; }
  
  /* Flashcards */
  .flashcard { height: 260px; }
  .flashcard-front h2 { font-size: 24px; }
  .flashcard-front p { font-size: 14px; }
  .flashcard-back h3 { font-size: 18px; }
  
  /* Video Area */
  .video-container { padding-top: 56.25%; /* maintain 16:9 ratio */ }
  .video-notes-area { height: 300px; }
  
  /* Toast/Alerts */
  .toast-container { 
    left: 16px; 
    right: 16px; 
    top: 16px; 
    align-items: stretch;
  }
  .toast { min-width: 0; width: 100%; }

  /* Reading & Quizzes */
  .passage-content { padding: 16px; font-size: 15px; }
  .quiz-option { padding: 12px 14px; font-size: 14px; }
  
  /* Pronunciation */
  .pronunciation-area { padding: 24px; }
}

/* ===== RESPONSIVE DESIGN FOR SMARTPHONES (max-width: 480px) ===== */
@media (max-width: 480px) { 
  .stats-grid { grid-template-columns: 1fr; } 
  .vocab-grid { grid-template-columns: 1fr; }
  
  .landing-features { grid-template-columns: 1fr; }
  
  .hero-left h2 { font-size: 28px; }
  .hero-mascot { width: 180px; height: 180px; }
  
  .landing-nav { flex-direction: column; }
  .landing-nav-btns { width: 100%; justify-content: center; margin-top: 8px; }
  
  .day-btn { width: 38px; height: 38px; font-size: 13px; }
  
  .auth-card { padding: 24px 16px; }
  .company-card { padding: 16px; }
  
  .flex-between { flex-direction: column; align-items: flex-start; gap: 8px; }
}

/* ===== MISC ===== */
.hidden { display: none !important; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }
.text-center { text-align: center; }
.flex { display: flex; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.gap-8 { gap: 8px; }
.gap-16 { gap: 16px; }

.mastery-stars { color: var(--gold); font-size: 16px; letter-spacing: 2px; }

.category-filter { display: flex; gap: 8px; margin-bottom: 16px; flex-wrap: wrap; }

.filter-btn {
  padding: 8px 18px; border: 2px solid var(--border); background: white;
  color: var(--text-secondary); border-radius: 20px; cursor: pointer;
  font-size: 13px; font-weight: 800; transition: var(--transition);
  border-bottom: 3px solid var(--border);
}
.filter-btn.active, .filter-btn:hover {
  background: var(--leaf); color: white; border-color: var(--leaf-dark);
}

.loading { display: flex; align-items: center; justify-content: center; padding: 40px; }

.spinner {
  width: 40px; height: 40px; border: 4px solid var(--border);
  border-top-color: var(--leaf); border-radius: 50%; animation: spin 0.8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ===== LANGUAGE SWITCHER ===== */
.lang-switcher {
  display: flex; gap: 4px; background: white; padding: 3px;
  border-radius: 30px; border: 2px solid var(--border);
  box-shadow: var(--shadow);
}
.lang-btn {
  padding: 5px 12px; border: none; border-radius: 20px;
  background: transparent; color: var(--text-muted);
  font-size: 12px; font-weight: 800; cursor: pointer;
  transition: var(--transition); font-family: inherit;
}
.lang-btn.active { background: var(--leaf); color: white; }
.lang-btn:hover:not(.active) { background: var(--leaf-bg); color: var(--leaf-dark); }

/* ===== TOPIC CHIPS ===== */
.topic-chip {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 10px 16px; border-radius: 30px;
  border: 2px solid var(--border); background: white;
  color: var(--text-primary); font-size: 14px; font-weight: 700;
  cursor: pointer; transition: all 0.2s ease; font-family: inherit;
  user-select: none;
}
.topic-chip:hover {
  border-color: var(--chip-color, #4f46e5);
  background: color-mix(in srgb, var(--chip-color, #4f46e5) 8%, white);
  transform: translateY(-1px);
}
.topic-chip.selected {
  background: var(--chip-color, #4f46e5);
  color: white; border-color: var(--chip-color, #4f46e5);
  box-shadow: 0 2px 8px color-mix(in srgb, var(--chip-color, #4f46e5) 40%, transparent);
  transform: translateY(-1px);
}
.topic-chip-icon { font-size: 18px; }
.topic-chip-name { font-size: 13px; }

/* ===== SOCIAL LOGIN ===== */
.social-divider {
  display: flex; align-items: center; gap: 12px;
  margin: 20px 0; color: var(--text-muted); font-size: 13px; font-weight: 700;
}
.social-divider::before, .social-divider::after {
  content: ''; flex: 1; height: 2px; background: var(--border);
}

.btn-social {
  display: flex; align-items: center; justify-content: center; gap: 10px;
  width: 100%; padding: 12px 20px; border: 2px solid var(--border);
  border-bottom: 4px solid var(--border); border-radius: var(--radius);
  background: white; color: var(--text-primary); font-size: 14px;
  font-weight: 700; cursor: pointer; transition: var(--transition);
  font-family: inherit; margin-bottom: 16px;
}
.btn-social:hover { background: var(--bg-primary); transform: translateY(-1px); }
.btn-social:active { transform: translateY(2px); border-bottom-width: 2px; }

.btn-google:hover { border-color: #4285F4; }
.btn-facebook:hover { border-color: #1877F2; }
@keyframes confetti-fall { 0% { transform: translateY(0) rotate(0); opacity: 1; } 100% { transform: translateY(100vh) rotate(720deg); opacity: 0; } } @keyframes popIn { 0% { transform: scale(0.5); opacity: 0; } 100% { transform: scale(1); opacity: 1; } } @keyframes bounce { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-10px); } } @keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }