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

:root {
  --bg-color: #000000;
  --card-color: #1d1d1f;
  --text-primary: #f5f5f7;
  --text-secondary: #a1a1a6;
  --border-color: #30363d;
  --accent-blue: #007aff;
  --slider-track-color: #333;
  --slider-thumb-color: #f5f5f7;
  --transition-smooth: 500ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 200ms ease;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  margin: 0;
  overflow: hidden;
}

.page {
  position: absolute;
  width: 100%;
  height: 100vh;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--transition-smooth),
              transform var(--transition-smooth),
              filter 300ms ease;
  pointer-events: none;
  overflow-y: auto;
}
.page.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.page.is-blurred {
  filter: blur(8px) brightness(0.7);
  transform: scale(0.98);
  pointer-events: none;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem 2rem;
}

.login-page {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.login-page h1 { font-size: 2.5rem; font-weight: 600; }
.login-page p { color: var(--text-secondary); }

.login-form { width: 100%; max-width: 320px; }
.form-group { position: relative; margin-bottom: 1rem; }

.form-input {
  width: 100%;
  padding: 0.75rem 1rem;
  background-color: var(--card-color);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-primary);
  font-size: 1rem;
  box-sizing: border-box;
}

.password-toggle {
  position: absolute;
  top: 50%; right: 1rem;
  transform: translateY(-50%);
  cursor: pointer;
  width: 20px;
  height: 20px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23a1a1a6' stroke-width='2'%3E%3Cpath d='M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z'/%3E%3Ccircle cx='12' cy='12' r='3'/%3E%3C/svg%3E");
  background-size: contain;
  transition: opacity var(--transition-fast);
}
.password-toggle.visible {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23a1a1a6' stroke-width='2'%3E%3Cpath d='M17.94 17.94A10.07 10.07 0 0 1 12 20c-7 0-11-8-11-8a18.45 18.45 0 0 1 5.06-5.94M9.9 4.24A9.12 9.12 0 0 1 12 4c7 0 11 8 11 8a18.5 18.5 0 0 1-2.16 3.19m-6.72-1.07a3 3 0 1 1-4.24-4.24'/%3E%3Cline x1='1' y1='1' x2='23' y2='23'/%3E%3C/svg%3E");
}

.btn {
  width: 100%;
  padding: 0.75rem;
  background-color: var(--accent-blue);
  border-radius: 8px;
  border: none;
  color: white;
  font-weight: 500;
  cursor: pointer;
}
.error-box {
  color: #f87171;
  margin-top: 1rem;
  font-size: 0.9rem;
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 2rem;
}
.header h1 { font-size: 2.25rem; font-weight: 600; }
.btn-logout {
  background: var(--card-color);
  border: 1px solid var(--border-color);
  color: var(--accent-blue);
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 500;
  transition: all var(--transition-fast);
}
.btn-logout:hover { border-color: var(--accent-blue); }

.mode-toggle {
  position: relative;
  display: flex;
  background-color: var(--card-color);
  padding: 6px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  max-width: 500px;
  margin: 0 auto 2rem;
  overflow: hidden;
}

.mode-toggle-slider {
  position: absolute;
  top: 7px;
  left: 7px;
  height: calc(100% - 14px);
  background-color: var(--border-color);
  border-radius: 10px;
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1),
              width 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

.mode-toggle-btn {
  flex: 1;
  padding: 0.75rem 1rem;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 1rem;
  cursor: pointer;
  transition: color var(--transition-fast);
  z-index: 1;
}
.mode-toggle-btn.active { color: var(--text-primary); }

.mode-info {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin: 0.75rem 0 1.5rem;
  padding: 0.75rem 1rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  color: #ccc;
  font-size: 0.9rem;
  line-height: 1.5;
}

.calculators-wrapper { position: relative; }
.calculator-section {
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: opacity 300ms ease, transform 300ms ease;
}
.calculator-section.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.calculator-section:not(.visible) {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
}

.controls-container {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
  align-items: end;
  background-color: #151516;
  padding: 1.5rem 2rem;
  border-radius: 12px;
  margin-bottom: 3rem;
  border: 1px solid var(--border-color);
}
.control-group label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  display: block;
}

.select-input {
  width: 100%;
  padding: 0.75rem;
  background-color: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  border-radius: 8px;
  font-size: 1rem;
}

.date-picker-wrapper { position: relative; }

.date-picker-trigger {
  cursor: pointer;
  user-select: none;
  transition: all var(--transition-fast);
}
.date-picker-trigger:hover {
  border-color: var(--text-secondary);
}

.long-term-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 3rem;
}
.long-term-controls .date-picker-wrapper {
  flex: 1 1 260px;
}

.ios-calendar-container {
  position: absolute;
  z-index: 20;
  display: flex;
  gap: 1rem;
  background-color: var(--card-color);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 1rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  opacity: 0;
  transform: translateY(10px) scale(0.95);
  transition: opacity 250ms ease, transform 250ms ease;
  pointer-events: none;
  margin-top: 0.5rem;
}
.ios-calendar-container.visible {
  opacity: 1;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.calendar-main,
.bunk-calendar-main {
  width: 100%;
  max-width: 320px;
}

.calendar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0.25rem;
  margin-bottom: 0.5rem;
}
.calendar-month-year { font-weight: 600; font-size: 1.1rem; }
.calendar-nav {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 8px;
  transition: background-color var(--transition-fast);
}
.calendar-nav:hover { background-color: var(--border-color); }
.calendar-nav svg {
  stroke: var(--text-secondary);
  width: 18px;
  height: 18px;
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 4px;
  text-align: center;
  opacity: 1;
  transition: opacity 150ms ease-in-out;
}
.calendar-grid.is-changing { opacity: 0; }

.calendar-day, .calendar-weekday {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.calendar-day.is-bunk-selected {
  background: rgba(138, 77, 255, 0.25);
  box-shadow: inset 0 0 0 2px #8a4dff;
  border-radius: 6px;
  color: #fff;
  font-weight: 600;
}

.calendar-weekday {
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: default;
}

.calendar-day:hover { background-color: var(--border-color); }
.calendar-day.is-other-month {
  color: var(--text-secondary);
  opacity: 0.5;
  pointer-events: none;
}
.calendar-day.is-today {
  color: var(--accent-blue);
  font-weight: 700;
}

.calendar-day.is-holiday, .calendar-day.is-sunday { color: #ff4d4d; }
.calendar-day.is-holiday::after, .calendar-day.is-sunday::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background-color: #ff4d4d;
}
.calendar-day.is-isa { color: #30d158; }
.calendar-day.is-isa::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background-color: #30d158;
}
.calendar-day.is-event { color: #ffd60a; }
.calendar-day.is-event::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background-color: #ffd60a;
}

.calendar-day.is-selected {
  background-color: var(--accent-blue);
  color: #fff !important;
}
.calendar-day.is-class-day.is-bunked {
  background: rgba(255, 90, 90, 0.6);
  border-radius: 6px;
  color: #fff;
}

.calendar-day.is-bunk-selected {
  background: rgba(138, 77, 255, 0.25);
  box-shadow: inset 0 0 0 2px #8a4dff;
  border-radius: 6px;
  color: #fff;
  font-weight: 600;
}

.calendar-legend {
  width: 180px;
  padding-left: 1rem;
  border-left: 1px solid var(--border-color);
}
.legend-title {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}
.legend-item {
  display: flex;
  align-items: center;
  margin-bottom: 0.75rem;
}
.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  margin-right: 0.75rem;
}
.legend-dot.dot-holiday { background-color: #ff4d4d; }
.legend-dot.dot-isa { background-color: #30d158; }
.legend-dot.dot-event { background-color: #ffd60a; }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 8px;
  background: var(--slider-track-color);
  border-radius: 5px;
  outline: none;
  transition: background 0.3s ease-in-out;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  background: var(--slider-thumb-color);
  border-radius: 50%;
  cursor: pointer;
  border: 3px solid #151516;
  box-shadow: 0 0 5px rgba(0,0,0,0.5);
}
#slider-value { text-align: right; font-weight: 500; }

.courses-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

.course-card {
  background-color: var(--card-color);
  padding: 1.5rem;
  border-radius: 18px;
  border: 1px solid var(--border-color);
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--transition-smooth) 100ms, transform var(--transition-smooth) 100ms;
  position: relative;
  overflow: hidden;
  cursor: pointer;
}
.course-card.visible { opacity: 1; transform: translateY(0); }
.course-card::before {
  content: "";
  position: absolute;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: conic-gradient(transparent, rgba(0,122,255,0.5), transparent 30%);
  animation: spin 4s linear infinite;
  animation-play-state: paused;
  opacity: 0;
  transition: opacity var(--transition-fast);
}
.course-card:hover::before {
  animation-play-state: running;
  opacity: 1;
}
.course-card::after {
  content: "";
  position: absolute;
  inset: 2px;
  background: var(--card-color);
  border-radius: 16px;
}
.card-content {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  height: 100%;
}
.course-card h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 0.5rem 0;
  min-height: 56px;
}
.course-card .course-code {
  color: var(--text-secondary);
  margin-bottom: auto;
  padding-bottom: 1.5rem;
}
.course-card .info-row {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: baseline;
  gap: 0.5rem;
}
.course-card .info-label { color: var(--text-secondary); }
.course-card .info-value b {
  color: var(--text-primary);
  font-weight: 500;
}
.course-card .bunk-count {
  font-size: 3rem;
  font-weight: 700;
  color: var(--text-primary);
}

.loader-container {
  position: fixed;
  inset: 0;
  z-index: 10;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
}
.loader-container.visible {
  opacity: 1;
  pointer-events: auto;
}
.loader-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(5px);
}
.loader {
  width: 48px;
  height: 48px;
  border: 3px solid #fff;
  border-bottom-color: var(--accent-blue);
  border-radius: 50%;
  box-sizing: border-box;
  animation: rotation 1s linear infinite;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
@keyframes rotation {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.modal-container {
  position: fixed;
  inset: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 300ms ease;
}
.modal-container.visible {
  opacity: 1;
  pointer-events: auto;
}
.modal-backdrop {
  position: absolute;
  inset: 0;
}
.modal {
  background-color: var(--card-color);
  border: 1px solid var(--border-color);
  border-radius: 18px;
  width: 90%;
  max-width: 800px;
  padding: 2rem;
  box-shadow: 0 20px 40px rgba(0,0,0,0.4);
  transform: scale(0.95);
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1);
}
.modal-container.visible .modal { transform: scale(1); }

.modal-close-btn {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: var(--border-color);
  border: none;
  color: var(--text-secondary);
  width: 30px;
  height: 30px;
  border-radius: 50%;
  font-size: 1.5rem;
  line-height: 30px;
  text-align: center;
  cursor: pointer;
  transition: background-color var(--transition-fast);
}
.modal-close-btn:hover {
  background-color: #555;
  color: var(--text-primary);
}

.modal h2 { margin-top: 0; font-size: 1.5rem; }
.modal p { color: var(--text-secondary); line-height: 1.6; }
.modal p b { color: var(--text-primary); font-weight: 500; }

.modal-section {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
}
.modal-section h3 {
  margin-top: 0;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-secondary);
}
.modal-content-wrapper {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 2.5rem;
}
.modal-calendar-grid .calendar-day {
  height: 36px;
  width: 36px;
  font-size: 0.9rem;
  border-radius: 50%;
}
.modal-calendar-grid .calendar-day.is-class-day {
  background-color: var(--class-day-color, rgba(0, 122, 255, 0.2));
}
.modal-calendar-grid .calendar-day:hover { background-color: var(--border-color); }
.modal-calendar-grid .calendar-day.is-class-day:hover { cursor: pointer; }

.modal-calendar-legend { margin-top: 1.5rem; }
.modal-legend-item { display: flex; align-items: center; margin-bottom: 0.5rem; }
.modal-legend-gradient {
  width: 100%;
  height: 10px;
  border-radius: 5px;
  background: linear-gradient(to right, #30d158, #ffd60a, #ff4d4d);
  margin-bottom: 0.25rem;
}
.modal-legend-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-secondary);
}
.modal-timings-list {
  margin-top: 1.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: opacity 200ms ease;
}
.modal-timings-list span {
  color: var(--text-primary);
  font-weight: 500;
}

.legend-item label {
  font-size: 0.9rem;
  flex-grow: 1;
  cursor: pointer;
  user-select: none;
}
.legend-item input[type="checkbox"] {
  -webkit-appearance: none;
  appearance: none;
  background-color: var(--bg-color);
  margin: 0;
  font: inherit;
  color: currentColor;
  width: 1.15em;
  height: 1.15em;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  transform: translateY(-0.075em);
  display: grid;
  place-content: center;
  cursor: pointer;
  margin-left: auto;
}
.legend-item input[type="checkbox"]::before {
  content: "";
  width: 0.65em;
  height: 0.65em;
  transform: scale(0);
  transition: 120ms transform ease-in-out;
  box-shadow: inset 1em 1em var(--accent-blue);
  transform-origin: bottom left;
  clip-path: polygon(14% 44%, 0 65%, 50% 100%, 100% 16%, 80% 0%, 43% 62%);
}
.legend-item input[type="checkbox"]:checked::before {
  transform: scale(1);
}

.projection-summary {
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
}

.projection-summary b {
  color: var(--text-primary);
  font-weight: 600;
}

.projection-line + .projection-line {
  margin-top: 0.25rem;
}

@media (max-width: 1024px) {
  .controls-container {
    grid-template-columns: repeat(2, 1fr);
  }
  .courses-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .container { padding: 1rem; }
  .header h1 { font-size: 1.75rem; }
  .login-page h1 { font-size: 1.75rem; }

  .controls-container {
    grid-template-columns: 1fr;
    gap: 1rem;
    padding: 1rem;
  }
  #slider-value { text-align: left; }

  .courses-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
  .course-card .bunk-count { font-size: 2.5rem; }
  .course-card h2 { min-height: auto; }

  .modal-content-wrapper { grid-template-columns: 1fr; }

  /* Mode toggle */
  .mode-toggle {
    flex-direction: column;
    width: 100%;
  }
  .mode-toggle-btn {
    width: 100%;
    border-radius: 8px;
    margin: 3px 0;
  }
  .mode-toggle-slider {
    display: none;
  }
  .mode-toggle-btn.active {
    background-color: var(--border-color);
    color: var(--text-primary);
  }

  /* Calendar responsiveness */
  .ios-calendar-container {
    flex-direction: column;
    max-width: calc(100vw - 2rem);
  }
  .calendar-legend {
    width: 100%;
    padding: 1rem 0 0 0;
    border-left: none;
    border-top: 1px solid var(--border-color);
  }
  .calendar-grid {
    gap: 2px;
  }
  .calendar-day {
    height: 36px;
    font-size: 0.875rem;
  }

  /* Touch targets */
  .password-toggle {
    width: 44px;
    height: 44px;
    background-size: 20px;
    background-position: center;
    background-repeat: no-repeat;
  }
  .calendar-nav {
    min-width: 44px;
    min-height: 44px;
  }
  .modal-close-btn {
    width: 44px;
    height: 44px;
    top: 0.5rem;
    right: 0.5rem;
  }

  /* Modal */
  .modal {
    padding: 1.25rem;
    width: 95%;
  }
}

@media (max-width: 375px) {
  .container { padding: 0.75rem; }

  .modal {
    padding: 1rem;
  }

  .calendar-day {
    height: 32px;
    font-size: 0.8rem;
  }
}