/* ==========================================================================
   VERCEL GEIST DESIGN SYSTEM - STUDENT ATTENDANCE MANAGER
   Tailored to exact specifications in DESIGN.md
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Geist:wght@300;400;500;600;700&family=Geist+Mono:wght@400;500;600&display=swap');

:root {
  --font-sans: 'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Geist Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

  /* Vercel Light Palette (from DESIGN.md) */
  --color-canvas: #fafafa;
  --color-canvas-elevated: #ffffff;
  --color-ink: #171717;
  --color-body: #4d4d4d;
  --color-mute: #888888;
  --color-faint: #b3b3b3;
  --color-hairline: #eaeaea;
  --color-hairline-soft: #f4f4f4;

  /* Accents */
  --color-primary: #171717;
  --color-on-primary: #ffffff;
  --color-blue: #0070f3;
  --color-blue-deep: #0761d1;
  --color-blue-soft: #edf5ff;

  --color-success: #059669;
  --color-success-soft: #ecfdf5;
  --color-success-border: #a7f3d0;

  --color-warning: #d97706;
  --color-warning-soft: #fffbeb;
  --color-warning-border: #fde68a;

  --color-error: #e11d48;
  --color-error-soft: #fef2f2;
  --color-error-border: #fecaca;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-pill: 9999px;

  --shadow-subtle: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.05), 0 1px 2px rgba(0, 0, 0, 0.03);
  --shadow-modal: 0 20px 40px -15px rgba(0, 0, 0, 0.2);
}

.dark {
  --color-canvas: #000000;
  --color-canvas-elevated: #0a0a0a;
  --color-ink: #ededed;
  --color-body: #a1a1a1;
  --color-mute: #707070;
  --color-faint: #444444;
  --color-hairline: #222222;
  --color-hairline-soft: #141414;

  --color-primary: #ededed;
  --color-on-primary: #000000;
  --color-blue: #0070f3;
  --color-blue-deep: #3291ff;
  --color-blue-soft: #081a33;

  --color-success: #10b981;
  --color-success-soft: #062b1a;
  --color-success-border: #065f46;

  --color-warning: #f59e0b;
  --color-warning-soft: #301f05;
  --color-warning-border: #78350f;

  --color-error: #f43f5e;
  --color-error-soft: #380d19;
  --color-error-border: #881337;

  --shadow-subtle: 0 1px 2px rgba(0, 0, 0, 0.6);
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.8);
  --shadow-modal: 0 24px 48px -12px rgba(0, 0, 0, 0.95);
}

/* ==================== GLOBAL RESETS & TYPOGRAPHY ==================== */

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

html {
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.5;
  background-color: var(--color-canvas);
  color: var(--color-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--color-canvas);
  color: var(--color-body);
  overflow-x: hidden;
  position: relative;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--color-ink);
  font-weight: 600;
  letter-spacing: -0.025em;
}

.font-mono {
  font-family: var(--font-mono) !important;
}

/* App Max-Width Container */
.app-container {
  width: 100%;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

@media (max-width: 640px) {
  .app-container {
    padding-left: 16px;
    padding-right: 16px;
  }
}

/* Vercel Mesh Glow Effect in Hero */
.vercel-mesh-glow {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  max-width: 1100px;
  height: 220px;
  background: radial-gradient(circle at 50% 0%, 
    rgba(0, 112, 243, 0.12) 0%, 
    rgba(121, 40, 202, 0.08) 35%, 
    rgba(255, 0, 128, 0.04) 65%, 
    transparent 100%);
  pointer-events: none;
  z-index: 0;
  filter: blur(40px);
}

.dark .vercel-mesh-glow {
  background: radial-gradient(circle at 50% 0%, 
    rgba(0, 112, 243, 0.18) 0%, 
    rgba(121, 40, 202, 0.12) 40%, 
    rgba(255, 0, 128, 0.07) 70%, 
    transparent 100%);
}

/* ==================== HEADER & NAVBAR ==================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  width: 100%;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-hairline);
  transition: background-color 0.2s, border-color 0.2s;
}

.dark .site-header {
  background: rgba(0, 0, 0, 0.88);
}

.nav-row-main {
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-wrapper {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-logo-triangle {
  width: 26px;
  height: 26px;
  background: var(--color-ink);
  color: var(--color-canvas);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

.brand-title {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-ink);
}

.brand-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  font-size: 11px;
  font-family: var(--font-mono);
  background: var(--color-hairline-soft);
  color: var(--color-mute);
  border: 1px solid var(--color-hairline);
}

/* Secondary Navigation Tab Bar */
.nav-row-tabs {
  display: flex;
  align-items: center;
  gap: 28px;
  border-top: 1px solid var(--color-hairline);
  overflow-x: auto;
}

.nav-tab-item {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 10px 0;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  color: var(--color-mute);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease;
}

.nav-tab-item:hover {
  color: var(--color-ink);
}

.nav-tab-item.active {
  color: var(--color-ink);
  border-bottom-color: var(--color-ink);
  font-weight: 600;
}

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

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  background-color: var(--color-primary);
  color: var(--color-on-primary);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  height: 34px;
  padding: 0 14px;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn-primary:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  background-color: var(--color-canvas-elevated);
  color: var(--color-ink);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  height: 34px;
  padding: 0 12px;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn-ghost:hover {
  background-color: var(--color-hairline-soft);
  border-color: var(--color-faint);
}

.btn-icon-sq {
  width: 34px;
  height: 34px;
  padding: 0 !important;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* ==================== KPI / STAT METRICS GRID ==================== */

.kpi-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  margin-top: 24px;
  margin-bottom: 24px;
}

@media (max-width: 900px) {
  .kpi-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 540px) {
  .kpi-grid {
    grid-template-columns: 1fr;
  }
}

.kpi-card {
  background: var(--color-canvas-elevated);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-md);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 98px;
  box-shadow: var(--shadow-subtle);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.kpi-card:hover {
  border-color: var(--color-faint);
}

.kpi-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-mute);
}

.kpi-card-body {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-top: 10px;
}

.kpi-number {
  font-size: 26px;
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1;
  color: var(--color-ink);
}

.kpi-subtext {
  font-size: 12px;
  color: var(--color-mute);
}

/* ==================== TOOLBAR (SEARCH & FILTERS) ==================== */

.toolbar-card {
  background: var(--color-canvas-elevated);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  box-shadow: var(--shadow-subtle);
}

.search-container {
  position: relative;
  flex: 1;
  max-width: 380px;
  min-width: 240px;
}

.search-icon-fixed {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 15px;
  height: 15px;
  color: var(--color-mute);
  pointer-events: none;
}

.search-input-field {
  width: 100%;
  height: 36px;
  padding-left: 36px !important;
  padding-right: 56px !important;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--color-ink);
  background: var(--color-canvas);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-sm);
  outline: none;
  transition: all 0.15s ease;
}

.search-input-field:focus {
  background: var(--color-canvas-elevated);
  border-color: var(--color-ink);
  box-shadow: 0 0 0 1px var(--color-ink);
}

.search-kbd-pill {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 10px;
  padding: 2px 5px;
  border-radius: 4px;
  background: var(--color-hairline-soft);
  border: 1px solid var(--color-hairline);
  color: var(--color-mute);
  pointer-events: none;
}

.filter-group {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.filter-select {
  height: 36px;
  padding: 0 28px 0 12px;
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  color: var(--color-ink);
  background: var(--color-canvas);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-sm);
  outline: none;
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23888' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 8px center;
  background-size: 14px;
  transition: all 0.15s ease;
}

.filter-select:focus {
  border-color: var(--color-ink);
}

/* ==================== DATA TABLE ==================== */

.table-wrapper-card {
  background: var(--color-canvas-elevated);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-card);
}

.table-responsive-container {
  width: 100%;
  overflow-x: auto;
}

.vercel-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 13px;
}

.vercel-table th {
  padding: 12px 16px;
  background: var(--color-canvas);
  border-bottom: 1px solid var(--color-hairline);
  color: var(--color-mute);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  white-space: nowrap;
}

.vercel-table td {
  padding: 13px 16px;
  border-bottom: 1px solid var(--color-hairline-soft);
  color: var(--color-ink);
  vertical-align: middle;
  transition: background-color 0.12s ease;
}

.vercel-table tr:last-child td {
  border-bottom: none;
}

.vercel-table tbody tr:hover td {
  background-color: var(--color-hairline-soft);
}

/* Student avatar in table */
.student-avatar {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--color-hairline-soft);
  border: 1px solid var(--color-hairline);
  color: var(--color-ink);
  font-size: 11px;
  font-weight: 600;
  font-family: var(--font-mono);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.student-name-btn {
  background: none;
  border: none;
  padding: 0;
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  transition: color 0.15s ease;
}

.student-name-btn:hover {
  color: var(--color-blue);
  text-decoration: underline;
}

/* Progress bar in table */
.progress-bar-wrap {
  width: 110px;
  height: 6px;
  background: var(--color-hairline-soft);
  border-radius: var(--radius-pill);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  border-radius: var(--radius-pill);
  transition: width 0.3s ease;
}

/* ==================== BADGES ==================== */

.badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.01em;
  border: 1px solid transparent;
  line-height: 1.2;
}

.badge-neutral {
  background-color: var(--color-hairline-soft);
  color: var(--color-body);
  border-color: var(--color-hairline);
}

.badge-success {
  background-color: var(--color-success-soft);
  color: var(--color-success);
  border-color: var(--color-success-border);
}

.badge-warning {
  background-color: var(--color-warning-soft);
  color: var(--color-warning);
  border-color: var(--color-warning-border);
}

.badge-error {
  background-color: var(--color-error-soft);
  color: var(--color-error);
  border-color: var(--color-error-border);
}

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  display: inline-block;
  flex-shrink: 0;
}

/* Table Actions group */
.action-buttons-group {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.action-btn {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  background: transparent;
  border: 1px solid transparent;
  color: var(--color-mute);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.12s ease;
}

.action-btn:hover {
  background: var(--color-hairline);
  color: var(--color-ink);
  border-color: var(--color-hairline);
}

.action-btn-danger:hover {
  background: var(--color-error-soft);
  color: var(--color-error);
  border-color: var(--color-error-border);
}

/* ==================== ATTENDANCE REGISTER ==================== */

.register-control-panel {
  background: var(--color-canvas-elevated);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  margin-bottom: 16px;
  box-shadow: var(--shadow-subtle);
}

.register-date-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--color-hairline);
  flex-wrap: wrap;
  gap: 12px;
}

.register-batch-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  flex-wrap: wrap;
  gap: 12px;
}

.segmented-status-control {
  display: inline-flex;
  background: var(--color-canvas);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-sm);
  padding: 2px;
  gap: 2px;
}

.segmented-status-btn {
  background: transparent;
  border: none;
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  color: var(--color-mute);
  transition: all 0.12s ease;
}

.segmented-status-btn:hover {
  color: var(--color-ink);
}

.segmented-status-btn.active-present {
  background: var(--color-success);
  color: #ffffff;
  font-weight: 600;
  box-shadow: 0 1px 2px rgba(5, 150, 105, 0.3);
}

.segmented-status-btn.active-late {
  background: var(--color-warning);
  color: #ffffff;
  font-weight: 600;
  box-shadow: 0 1px 2px rgba(217, 119, 6, 0.3);
}

.segmented-status-btn.active-absent {
  background: var(--color-error);
  color: #ffffff;
  font-weight: 600;
  box-shadow: 0 1px 2px rgba(225, 29, 72, 0.3);
}

/* ==================== ANALYTICS VIEW ==================== */

.analytics-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

@media (max-width: 768px) {
  .analytics-grid {
    grid-template-columns: 1fr;
  }
}

.analytics-card {
  background: var(--color-canvas-elevated);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-subtle);
}

.analytics-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

/* ==================== MODALS ==================== */

.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.18s ease;
  padding: 16px;
}

.modal-backdrop.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-dialog {
  background: var(--color-canvas-elevated);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-modal);
  width: 100%;
  max-width: 480px;
  max-height: 90vh;
  overflow-y: auto;
  padding: 24px;
  transform: scale(0.97) translateY(6px);
  transition: transform 0.18s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-backdrop.active .modal-dialog {
  transform: scale(1) translateY(0);
}

.form-label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-mute);
  margin-bottom: 6px;
}

.form-input, .form-select {
  width: 100%;
  height: 38px;
  padding: 0 12px;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--color-ink);
  background: var(--color-canvas);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-sm);
  outline: none;
  transition: all 0.15s ease;
}

.form-input:focus, .form-select:focus {
  background: var(--color-canvas-elevated);
  border-color: var(--color-ink);
  box-shadow: 0 0 0 1px var(--color-ink);
}

/* ==================== TOAST NOTIFICATIONS ==================== */

#toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 100;
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  min-width: 260px;
  max-width: 380px;
  padding: 10px 14px;
  background: var(--color-canvas-elevated);
  color: var(--color-ink);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-card);
  font-size: 13px;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 10px;
  animation: toastSlide 0.18s ease forwards;
  transition: all 0.18s ease;
}

@keyframes toastSlide {
  from {
    transform: translateY(8px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

/* ==================== FOOTER ==================== */

.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--color-hairline);
  background: var(--color-canvas-elevated);
  padding: 20px 0;
  font-size: 12px;
  color: var(--color-mute);
}

.footer-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}