/* ==========================================================================
   Student Grade Dashboard — design system
   Clean, calm, iOS-inspired. Mobile-first, max content width ~480px.
   ========================================================================== */

:root {
  --bg: #f2f2f7;
  --card: #ffffff;
  --text: #1c1c1e;
  --text-secondary: #8e8e93;
  --accent: #2563eb;
  --accent-soft: #dbe6ff;
  --separator: #e5e5ea;
  --track: #e9e9ee;
  --danger: #ff3b30;

  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 6px 16px rgba(0, 0, 0, 0.05);
  --gap: 16px;
  --max-width: 480px;
  --tabbar-height: 64px;

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

/* Dark theme placeholder — toggled from Settings. Tweak freely. */
[data-theme="dark"] {
  --bg: #000000;
  --card: #1c1c1e;
  --text: #ffffff;
  --text-secondary: #8e8e93;
  --accent: #2f6bff;
  --accent-soft: #1e2a4a;
  --separator: #2c2c2e;
  --track: #2c2c2e;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.5);
}

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  font-size: 16px;
  line-height: 1.4;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* Centered mobile column on desktop */
.shell {
  max-width: var(--max-width);
  margin: 0 auto;
  min-height: 100vh;
  position: relative;
  background: var(--bg);
}

/* ------------------------------ Typography ------------------------------ */
h1,
h2,
h3 {
  margin: 0;
  font-weight: 700;
}
.muted {
  color: var(--text-secondary);
}
.small {
  font-size: 13px;
}
a {
  color: var(--accent);
}

/* ------------------------------- Buttons -------------------------------- */
.btn {
  appearance: none;
  border: none;
  border-radius: var(--radius-sm);
  background: var(--accent);
  color: #fff;
  font-family: inherit;
  font-size: 16px;
  font-weight: 600;
  padding: 13px 18px;
  width: 100%;
  cursor: pointer;
  transition: opacity 0.15s ease, transform 0.05s ease;
}
.btn:active {
  transform: scale(0.985);
  opacity: 0.9;
}
.btn.secondary {
  background: var(--accent-soft);
  color: var(--accent);
}
.btn.ghost {
  background: transparent;
  color: var(--accent);
}
.btn.danger {
  background: transparent;
  color: var(--danger);
}
.btn:disabled {
  opacity: 0.5;
  cursor: default;
}

/* --------------------------------- Cards -------------------------------- */
.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: var(--gap);
  box-shadow: var(--shadow);
}

/* Colored circular course icon */
.icon-circle {
  width: 44px;
  height: 44px;
  min-width: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 18px;
}

/* Tappable list rows with a chevron */
.rows {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px var(--gap);
  border-bottom: 1px solid var(--separator);
  background: none;
  border-left: none;
  border-right: none;
  border-top: none;
  width: 100%;
  text-align: left;
  font-family: inherit;
  font-size: 16px;
  color: var(--text);
  cursor: pointer;
}
.row:last-child {
  border-bottom: none;
}
.row:active {
  background: var(--bg);
}
.row .row-main {
  flex: 1;
  min-width: 0;
}
.row .row-title {
  font-weight: 600;
}
.row .row-sub {
  color: var(--text-secondary);
  font-size: 13px;
}
.row .row-value {
  font-weight: 600;
  color: var(--text);
}
.chevron {
  color: var(--text-secondary);
  flex: none;
}
.chevron::after {
  content: "›";
  font-size: 22px;
  line-height: 1;
}

/* ------------------------------ App layout ------------------------------ */
.screen {
  padding: var(--gap);
  padding-bottom: calc(var(--tabbar-height) + 40px);
}
.screen.hidden {
  display: none;
}
.screen-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 6px 2px 16px;
}
.screen-header h1 {
  font-size: 30px;
  letter-spacing: -0.5px;
}

.section-label {
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.4px;
  margin: 22px 4px 8px;
}

/* Term range pill (tappable) */
.term-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--card);
  border: none;
  box-shadow: var(--shadow);
  color: var(--accent);
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  border-radius: 999px;
  padding: 8px 14px;
  cursor: pointer;
  margin-bottom: 12px;
}

/* Overall average card */
.overall {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}
.overall .big-number {
  font-size: 34px;
  font-weight: 800;
  letter-spacing: -1px;
}

/* Course card */
.course-card {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 12px;
  cursor: pointer;
}
.course-card:active {
  transform: scale(0.99);
}
.course-card .cc-main {
  flex: 1;
  min-width: 0;
}
.course-card .cc-code {
  font-weight: 700;
  font-size: 17px;
}
.course-card .cc-name {
  color: var(--text-secondary);
  font-size: 14px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.course-card .cc-meta {
  color: var(--text-secondary);
  font-size: 12px;
  margin-top: 2px;
}
.course-card .cc-mark {
  font-size: 26px;
  font-weight: 800;
  letter-spacing: -0.5px;
}
.course-card .cc-right {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Empty state */
.empty {
  text-align: center;
  color: var(--text-secondary);
  padding: 48px 20px;
}
.empty .emoji {
  font-size: 40px;
  display: block;
  margin-bottom: 10px;
}

/* ------------------------------- Tab bar -------------------------------- */
.tabbar {
  position: fixed;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  max-width: var(--max-width);
  height: var(--tabbar-height);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-top: 1px solid var(--separator);
  display: flex;
  z-index: 50;
  padding-bottom: env(safe-area-inset-bottom);
}
[data-theme="dark"] .tabbar {
  background: rgba(28, 28, 30, 0.9);
}
.tabbar button {
  flex: 1;
  background: none;
  border: none;
  font-family: inherit;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  font-size: 11px;
  cursor: pointer;
  padding: 8px 0;
}
.tabbar button.active {
  color: var(--accent);
}
.tabbar button svg {
  width: 24px;
  height: 24px;
}

/* Floating action button */
.fab {
  position: fixed;
  bottom: calc(var(--tabbar-height) + 18px);
  right: 20px; /* mobile / narrow: hug the right edge */
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  border: none;
  font-size: 30px;
  line-height: 1;
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.4);
  cursor: pointer;
  z-index: 49;
  display: flex;
  align-items: center;
  justify-content: center;
}
.fab:active {
  transform: scale(0.94);
}
/* On wider screens, keep the FAB anchored inside the centered 480px column. */
@media (min-width: 520px) {
  .fab {
    right: auto;
    left: 50%;
    /* 56px width + 20px inset = 76px from the column's right edge */
    transform: translateX(calc(var(--max-width) / 2 - 76px));
  }
  .fab:active {
    transform: translateX(calc(var(--max-width) / 2 - 76px)) scale(0.94);
  }
}

/* ---------------------------- Course detail ----------------------------- */
.detail-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px var(--gap);
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 10;
}
.back-btn {
  background: none;
  border: none;
  color: var(--accent);
  font-size: 17px;
  font-family: inherit;
  display: flex;
  align-items: center;
  gap: 2px;
  cursor: pointer;
  padding: 4px 6px 4px 0;
}
.back-btn::before {
  content: "‹";
  font-size: 26px;
  line-height: 1;
}
.detail-title {
  font-weight: 700;
  font-size: 17px;
}
.detail-actions {
  margin-left: auto;
}

/* Swipeable carousel */
.carousel {
  display: flex;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
  gap: 0;
  scrollbar-width: none;
}
.carousel::-webkit-scrollbar {
  display: none;
}
.panel {
  scroll-snap-align: center;
  flex: 0 0 100%;
  width: 100%;
  padding: 4px;
}
.panel .card {
  min-height: 230px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.dots {
  display: flex;
  justify-content: center;
  gap: 7px;
  margin: 12px 0 6px;
}
.dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--track);
  transition: background 0.2s, width 0.2s;
}
.dot.active {
  background: var(--accent);
  width: 20px;
  border-radius: 4px;
}

/* Gauge panel */
.gauge-wrap {
  text-align: center;
}
.gauge-label {
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.4px;
  margin-top: 4px;
}
.gauge-sub {
  color: var(--text-secondary);
  font-size: 14px;
  margin-top: 2px;
}

/* Info panel list */
.info-list {
  width: 100%;
}
.info-list .info-row {
  display: flex;
  justify-content: space-between;
  padding: 9px 2px;
  border-bottom: 1px solid var(--separator);
  font-size: 15px;
}
.info-list .info-row:last-child {
  border-bottom: none;
}
.info-list .info-row span:first-child {
  color: var(--text-secondary);
}
.info-list .info-row span:last-child {
  font-weight: 600;
}

/* Chart panel */
.chart-box {
  width: 100%;
  height: 200px;
}

/* Segmented control (Evaluations / Breakdown) */
.segmented {
  display: flex;
  background: var(--track);
  border-radius: var(--radius-sm);
  padding: 3px;
  margin: 18px 0 12px;
}
.segmented button {
  flex: 1;
  border: none;
  background: none;
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  padding: 8px;
  border-radius: 8px;
  cursor: pointer;
}
.segmented button.active {
  background: var(--card);
  box-shadow: var(--shadow);
  color: var(--accent);
}

/* ------------------------------- Modals --------------------------------- */
.sheet-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  z-index: 100;
  opacity: 0;
  transition: opacity 0.2s ease;
}
.sheet-backdrop.show {
  opacity: 1;
}
.sheet {
  background: var(--bg);
  width: 100%;
  max-width: var(--max-width);
  border-radius: 20px 20px 0 0;
  padding: 10px var(--gap) calc(20px + env(safe-area-inset-bottom));
  max-height: 92vh;
  overflow-y: auto;
  transform: translateY(100%);
  transition: transform 0.25s ease;
}
.sheet-backdrop.show .sheet {
  transform: translateY(0);
}
.sheet-grabber {
  width: 38px;
  height: 5px;
  border-radius: 3px;
  background: var(--track);
  margin: 6px auto 12px;
}
.sheet h2 {
  font-size: 20px;
  margin-bottom: 14px;
  text-align: center;
}

/* Forms */
.field {
  margin-bottom: 14px;
}
.field label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  margin: 0 2px 6px;
}
.field input,
.field select {
  width: 100%;
  font-family: inherit;
  font-size: 16px;
  color: var(--text);
  background: var(--card);
  border: 1px solid var(--separator);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  appearance: none;
}
.field input:focus,
.field select:focus {
  outline: none;
  border-color: var(--accent);
}
.field-row {
  display: flex;
  gap: 12px;
}
.field-row .field {
  flex: 1;
}
.form-actions {
  margin-top: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.error-text {
  color: var(--danger);
  font-size: 14px;
  margin: 8px 2px;
  min-height: 18px;
}

/* ------------------------------ Auth page ------------------------------- */
.auth-wrap {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 24px;
  max-width: var(--max-width);
  margin: 0 auto;
}
.auth-logo {
  text-align: center;
  margin-bottom: 28px;
}
.auth-logo .mark {
  width: 64px;
  height: 64px;
  border-radius: 18px;
  background: var(--accent);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 32px;
  font-weight: 800;
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.35);
}
.auth-logo h1 {
  font-size: 26px;
  margin-top: 14px;
}
.auth-logo p {
  color: var(--text-secondary);
  margin: 6px 0 0;
}
.auth-card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
}
.auth-toggle {
  text-align: center;
  margin-top: 18px;
  color: var(--text-secondary);
  font-size: 15px;
}
.auth-toggle button {
  background: none;
  border: none;
  color: var(--accent);
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  font-family: inherit;
}

/* iOS-style toggle switch */
.switch {
  position: relative;
  display: inline-block;
  width: 51px;
  height: 31px;
  flex: none;
}
.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}
.switch::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--track);
  border-radius: 999px;
  transition: background 0.2s ease;
}
.switch::before {
  content: "";
  position: absolute;
  z-index: 1;
  top: 2px;
  left: 2px;
  width: 27px;
  height: 27px;
  background: #fff;
  border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
  transition: transform 0.2s ease;
}
.switch:has(input:checked)::after {
  background: #34c759;
}
.switch:has(input:checked)::before {
  transform: translateX(20px);
}

/* Small helpers */
.spinner {
  width: 20px;
  height: 20px;
  border: 2.5px solid rgba(255, 255, 255, 0.4);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  display: inline-block;
  vertical-align: middle;
}
@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}
.center-loader {
  text-align: center;
  color: var(--text-secondary);
  padding: 60px 20px;
}
.hidden {
  display: none !important;
}