/* ===== DESIGN TOKENS ===== */
:root {
  --bg-deep: #0d1117;
  --bg-surface: #161b22;
  --bg-card: rgba(22, 27, 34, 0.85);
  --glass-border: rgba(255, 255, 255, 0.06);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);

  --accent: #2dd4bf;          /* teal */
  --accent-glow: rgba(45, 212, 191, 0.25);
  --accent-dark: #0f766e;
  --coral: #f97066;           /* coral for contrast */
  --coral-glow: rgba(249, 112, 102, 0.2);
  --amber: #fbbf24;

  --text: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #484f58;

  --radius: 14px;
  --radius-sm: 8px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);

  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ===== RESET ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg-deep);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
  background-image:
    radial-gradient(ellipse 80% 50% at 50% -20%, var(--accent-glow), transparent),
    radial-gradient(ellipse 60% 40% at 80% 100%, var(--coral-glow), transparent);
}

/* ===== HEADER ===== */
#app-header {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.75rem 1.5rem;
  background: rgba(13, 17, 23, 0.82);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--glass-border);
}
.logo { display: flex; align-items: center; gap: 0.5rem; font-weight: 700; font-size: 1.15rem; }
#main-nav { display: flex; gap: 0.25rem; }

.nav-btn {
  display: flex; align-items: center; gap: 0.4rem;
  padding: 0.5rem 1rem;
  border: none; border-radius: 999px;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font); font-size: 0.85rem; font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}
.nav-btn:hover { color: var(--text); background: rgba(255,255,255,0.05); }
.nav-btn.active {
  background: var(--accent-dark);
  color: #fff;
  box-shadow: 0 0 12px var(--accent-glow);
}

/* ===== MAIN ===== */
#app-main { max-width: 900px; margin: 0 auto; padding: 2rem 1.25rem 4rem; }

.tab-content { display: none; animation: fadeUp 0.35s ease; }
.tab-content.active { display: block; }
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ===== GLASS CARD ===== */
.glass-card {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--glass-shadow);
  backdrop-filter: blur(8px);
}
.glass-card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 1rem; color: var(--accent); }

/* ===== BUTTONS ===== */
.btn-primary {
  padding: 0.6rem 1.6rem; border: none; border-radius: 999px;
  background: linear-gradient(135deg, var(--accent-dark), var(--accent));
  color: #fff; font-family: var(--font); font-size: 0.9rem; font-weight: 600;
  cursor: pointer; transition: var(--transition);
  box-shadow: 0 2px 12px var(--accent-glow);
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 4px 20px var(--accent-glow); }
.btn-primary:disabled { opacity: 0.4; cursor: not-allowed; transform: none; }

.btn-accent {
  padding: 0.6rem 1.6rem; border: none; border-radius: 999px;
  background: linear-gradient(135deg, #d97706, var(--amber));
  color: #1a1a1a; font-family: var(--font); font-size: 0.9rem; font-weight: 600;
  cursor: pointer; transition: var(--transition);
}
.btn-accent:hover { transform: translateY(-1px); }
.btn-accent:disabled { opacity: 0.35; cursor: not-allowed; transform: none; }

.btn-outline {
  padding: 0.6rem 1.6rem; border: 1.5px solid var(--accent); border-radius: 999px;
  background: transparent; color: var(--accent);
  font-family: var(--font); font-size: 0.9rem; font-weight: 600;
  cursor: pointer; transition: var(--transition);
}
.btn-outline:hover { background: rgba(45,212,191,0.08); }

.btn-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 42px; height: 42px; border: 1px solid var(--glass-border);
  border-radius: 50%; background: var(--bg-surface); color: var(--text-secondary);
  cursor: pointer; transition: var(--transition);
}
.btn-icon:hover { color: var(--accent); border-color: var(--accent); background: rgba(45,212,191,0.06); }

.btn-danger-sm {
  margin-top: 1rem; padding: 0.4rem 1rem; border: 1px solid var(--coral);
  border-radius: 999px; background: transparent; color: var(--coral);
  font-family: var(--font); font-size: 0.78rem; font-weight: 500;
  cursor: pointer; transition: var(--transition);
}
.btn-danger-sm:hover { background: rgba(249,112,102,0.12); }

/* ===== INPUTS ===== */
input[type="text"], input[type="number"], select {
  width: 100%; padding: 0.6rem 0.85rem;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  background: var(--bg-deep); color: var(--text);
  font-family: var(--font); font-size: 0.88rem;
  transition: var(--transition);
}
input:focus, select:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-glow); }
input[type="number"] { max-width: 80px; text-align: center; }

/* ====================== POMODORO ====================== */
.pomodoro-wrapper {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 2rem;
  align-items: start;
}

/* Settings */
.pomo-settings .setting-row {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 0.75rem;
}
.pomo-settings label { font-size: 0.82rem; color: var(--text-secondary); }

/* Timer area */
.pomo-timer-area { display: flex; flex-direction: column; align-items: center; }

.mode-tabs { display: flex; gap: 0.25rem; margin-bottom: 1.5rem; }
.mode-btn {
  padding: 0.45rem 1rem; border: 1px solid var(--glass-border);
  border-radius: 999px; background: var(--bg-surface);
  color: var(--text-secondary); font-family: var(--font); font-size: 0.82rem; font-weight: 500;
  cursor: pointer; transition: var(--transition);
}
.mode-btn:hover { border-color: var(--accent); color: var(--text); }
.mode-btn.active { background: var(--accent-dark); color: #fff; border-color: var(--accent-dark); }

/* Timer Ring */
.timer-ring-container { position: relative; width: 240px; height: 240px; margin-bottom: 1.5rem; }
.timer-ring { width: 100%; height: 100%; transform: rotate(-90deg); }
.ring-bg { fill: none; stroke: var(--bg-surface); stroke-width: 8; }
.ring-progress {
  fill: none; stroke: var(--accent); stroke-width: 8;
  stroke-linecap: round;
  stroke-dasharray: 678.58;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.4s ease, stroke 0.3s ease;
}

.timer-display {
  position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
  font-size: 3.5rem; font-weight: 800; letter-spacing: -2px;
  font-variant-numeric: tabular-nums;
}
.timer-colon { animation: blink 1s step-end infinite; }
@keyframes blink { 50% { opacity: 0.3; } }

.timer-controls { display: flex; align-items: center; gap: 1rem; margin-bottom: 0.75rem; }
.round-info { font-size: 0.82rem; color: var(--text-muted); }

/* ====================== FLASH CARDS ====================== */
.fc-create { margin-bottom: 2rem; }
.fc-form { display: flex; flex-wrap: wrap; gap: 0.65rem; }
.fc-form input[type="text"] { flex: 1 1 200px; }
.fc-form .btn-primary { flex-shrink: 0; }

.fc-viewer { display: flex; flex-direction: column; align-items: center; }

.fc-empty { text-align: center; padding: 3rem 0; color: var(--text-muted); }
.fc-empty p { margin-top: 0.75rem; font-size: 0.9rem; }

/* Card flip */
.fc-card-wrapper { display: flex; flex-direction: column; align-items: center; }
.fc-card {
  width: 400px; height: 240px; perspective: 800px; cursor: pointer;
  margin-bottom: 0.5rem;
}
.fc-card-inner {
  position: relative; width: 100%; height: 100%;
  transition: transform 0.5s cubic-bezier(0.4,0,0.2,1);
  transform-style: preserve-3d;
}
.fc-card.flipped .fc-card-inner { transform: rotateY(180deg); }
.fc-face {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center; text-align: center;
  padding: 1.5rem; border-radius: var(--radius);
  backface-visibility: hidden;
  font-size: 1.15rem; font-weight: 600;
  word-break: break-word;
}
.fc-front {
  background: linear-gradient(135deg, var(--bg-surface), #1e2630);
  border: 1px solid var(--glass-border);
  color: var(--text);
}
.fc-back {
  background: linear-gradient(135deg, var(--accent-dark), #134e4a);
  color: #fff;
  transform: rotateY(180deg);
}

.fc-hint { font-size: 0.75rem; color: var(--text-muted); margin-bottom: 1rem; }
.fc-nav { display: flex; align-items: center; gap: 1rem; }
#fc-counter { font-size: 0.88rem; color: var(--text-secondary); min-width: 60px; text-align: center; }

/* ====================== QUIZ ====================== */
.quiz-create { margin-bottom: 2rem; }
.quiz-form { display: flex; flex-direction: column; gap: 0.6rem; }
.correct-row { display: flex; align-items: center; gap: 0.75rem; }
.correct-row label { font-size: 0.85rem; color: var(--text-secondary); white-space: nowrap; }
.correct-row select { max-width: 80px; }
.quiz-count { margin: 0.75rem 0 0.5rem; font-size: 0.82rem; color: var(--text-muted); }

/* Quiz progress */
.quiz-progress-bar {
  width: 100%; height: 6px; border-radius: 99px;
  background: var(--bg-surface); margin-bottom: 1.25rem; overflow: hidden;
}
.quiz-progress-fill {
  height: 100%; border-radius: 99px;
  background: linear-gradient(90deg, var(--accent-dark), var(--accent));
  transition: width 0.4s ease;
  width: 0%;
}

.quiz-q-counter { font-size: 0.82rem; color: var(--text-muted); margin-bottom: 0.5rem; }
.quiz-question-text { font-size: 1.25rem; font-weight: 700; margin-bottom: 1.25rem; line-height: 1.4; }

.quiz-options { display: flex; flex-direction: column; gap: 0.6rem; margin-bottom: 1.5rem; }
.quiz-opt-btn {
  width: 100%; padding: 0.85rem 1.1rem; text-align: left;
  border: 1.5px solid var(--glass-border); border-radius: var(--radius-sm);
  background: var(--bg-surface); color: var(--text);
  font-family: var(--font); font-size: 0.92rem; font-weight: 500;
  cursor: pointer; transition: var(--transition);
}
.quiz-opt-btn:hover { border-color: var(--accent); background: rgba(45,212,191,0.04); }
.quiz-opt-btn.selected { border-color: var(--accent); background: rgba(45,212,191,0.1); }
.quiz-opt-btn.correct { border-color: var(--accent); background: rgba(45,212,191,0.18); color: var(--accent); }
.quiz-opt-btn.wrong { border-color: var(--coral); background: rgba(249,112,102,0.12); color: var(--coral); }
.quiz-opt-btn:disabled { cursor: default; }

/* Quiz Results */
.quiz-results { text-align: center; padding: 2.5rem 1.5rem; }
.quiz-results h2 { font-size: 1.5rem; margin-bottom: 1.5rem; }

.results-circle { position: relative; width: 140px; height: 140px; margin: 0 auto 1.25rem; }
.results-circle svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.rc-bg { fill: none; stroke: var(--bg-deep); stroke-width: 8; }
.rc-fill {
  fill: none; stroke: var(--accent); stroke-width: 8;
  stroke-linecap: round;
  stroke-dasharray: 376.99;
  stroke-dashoffset: 376.99;
  transition: stroke-dashoffset 1s ease;
}
.rc-text {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.75rem; font-weight: 800;
}

#results-summary { margin-bottom: 1.5rem; color: var(--text-secondary); }
.results-btns { display: flex; gap: 0.75rem; justify-content: center; }

/* ===== RESPONSIVE ===== */
@media (max-width: 700px) {
  .pomodoro-wrapper { grid-template-columns: 1fr; }
  .fc-card { width: 100%; max-width: 360px; }
  #app-header { flex-direction: column; gap: 0.5rem; }
  #main-nav { width: 100%; justify-content: center; }
  .nav-btn { font-size: 0.78rem; padding: 0.4rem 0.75rem; }
}