/* =============================================
   ACADEMIC NIGHTINGALE DESIGN SYSTEM
   ============================================= */

/* Brand Colors */
:root {
  /* Primary - Cyan/Blue Theme */
  --color-primary-50: #ecfeff;
  --color-primary-100: #cffafe;
  --color-primary-200: #a5f3fc;
  --color-primary-300: #67e8f9;
  --color-primary-400: #22d3ee;
  --color-primary-500: #06b6d4;
  --color-primary-600: #0891b2;
  --color-primary-700: #0e7490;
  --color-primary-800: #155e75;
  --color-primary-900: #164e63;

  /* Neutral Colors */
  --color-gray-50: #f8fafc;
  --color-gray-100: #f1f5f9;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e1;
  --color-gray-400: #94a3b8;
  --color-gray-500: #64748b;
  --color-gray-600: #475569;
  --color-gray-700: #334155;
  --color-gray-800: #1e293b;
  --color-gray-900: #0f172a;

  /* Status Colors */
  --color-success: #10b981;
  --color-success-light: #d1fae5;
  --color-error: #ef4444;
  --color-error-light: #fee2e2;
  --color-warning: #f59e0b;
  --color-warning-light: #fef3c7;

  /* Background Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-accent: linear-gradient(135deg, #06b6d4 0%, #0891b2 50%, #0e7490 100%);
  --bg-subtle: linear-gradient(180deg, #ecfeff 0%, #f0f9ff 45%, #ffffff 100%);
  --bg-card: #ffffff;
  --bg-overlay: rgba(15, 23, 42, 0.1);

  /* Text Colors */
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-inverse: #ffffff;

  /* Border Colors */
  --border-light: rgba(226, 232, 240, 0.8);
  --border-medium: #e2e8f0;
  --border-strong: #cbd5e1;

  /* Shadows */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-brand: 0 18px 35px rgba(14, 116, 144, 0.12), 0 6px 18px rgba(8, 145, 178, 0.08);

  /* Border Radius */
  --radius-sm: 0.375rem;    /* 6px */
  --radius-md: 0.5rem;      /* 8px */
  --radius-lg: 0.75rem;     /* 12px */
  --radius-xl: 1rem;        /* 16px */
  --radius-2xl: 1.5rem;     /* 24px */
  --radius-3xl: 2rem;       /* 32px */

  /* Spacing Scale */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */

  /* Typography */
  --font-sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", Menlo, monospace;

  /* Font Sizes */
  --text-xs: 0.75rem;     /* 12px */
  --text-sm: 0.875rem;    /* 14px */
  --text-base: 1rem;      /* 16px */
  --text-lg: 1.125rem;    /* 18px */
  --text-xl: 1.25rem;     /* 20px */
  --text-2xl: 1.5rem;     /* 24px */
  --text-3xl: 1.875rem;   /* 30px */
  --text-4xl: 2.25rem;    /* 36px */
  --text-5xl: 3rem;       /* 48px */

  /* Font Weights */
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;
  --font-extrabold: 800;

  /* Line Heights */
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;

  /* Z-Index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
  --z-toast: 1080;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-light: rgba(51, 65, 85, 0.8);
    --border-medium: #334155;
    --border-strong: #475569;
  }
}

/* =============================================
   UTILITY CLASSES
   ============================================= */

/* Background utilities */
.bg-brand { background: var(--bg-accent); }
.bg-brand-light { background: var(--bg-subtle); }
.bg-card { background: var(--bg-card); }

/* Text utilities */
.text-brand { color: var(--color-primary-600); }
.text-brand-dark { color: var(--color-primary-700); }

/* Border utilities */
.border-brand { border-color: var(--color-primary-200); }
.rounded-brand { border-radius: var(--radius-xl); }

/* Shadow utilities */
.shadow-brand { box-shadow: var(--shadow-brand); }

/* =============================================
   COMPONENT BASE STYLES
   ============================================= */

/* Button Base Styles */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-lg);
  font-family: var(--font-sans);
  font-weight: var(--font-semibold);
  font-size: var(--text-sm);
  line-height: var(--leading-tight);
  transition: all var(--transition-fast);
  cursor: pointer;
  text-decoration: none;
  border: 1px solid transparent;
  outline: none;
  position: relative;
  overflow: hidden;
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  pointer-events: none;
}

/* Button Variants */
.btn-primary {
  background: var(--bg-accent);
  color: var(--text-inverse);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--bg-primary);
  color: var(--color-primary-700);
  border-color: var(--border-medium);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--bg-secondary);
  border-color: var(--color-primary-300);
}

.btn-ghost {
  background: transparent;
  color: var(--color-primary-600);
}

.btn-ghost:hover:not(:disabled) {
  background: var(--color-primary-50);
  color: var(--color-primary-700);
}

/* Button Sizes */
.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-xs);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

/* Input Base Styles */
.input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-lg);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--text-primary);
  background: var(--bg-primary);
  transition: all var(--transition-fast);
  outline: none;
}

.input:focus {
  border-color: var(--color-primary-500);
  box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.1);
}

.input::placeholder {
  color: var(--text-muted);
}

.input:disabled {
  background: var(--bg-secondary);
  color: var(--text-muted);
  cursor: not-allowed;
}

/* Card Base Styles */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.card-header {
  padding: var(--space-6);
  border-bottom: 1px solid var(--border-light);
}

.card-body {
  padding: var(--space-6);
}

.card-footer {
  padding: var(--space-6);
  border-top: 1px solid var(--border-light);
  background: var(--bg-secondary);
}

/* Modal Base Styles */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: var(--z-modal-backdrop);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
}

.modal {
  background: var(--bg-card);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-xl);
  max-width: 90vw;
  max-height: 90vh;
  overflow: hidden;
  z-index: var(--z-modal);
  animation: modalSlideIn var(--transition-normal) ease;
}

@keyframes modalSlideIn {
  from {
    opacity: 0;
    transform: translateY(-20px) scale(0.95);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

/* Toast Notification Styles */
.toast {
  position: fixed;
  top: var(--space-4);
  right: var(--space-4);
  z-index: var(--z-toast);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  min-width: 300px;
  max-width: 500px;
  animation: toastSlideIn var(--transition-normal) ease;
}

.toast-success {
  background: var(--color-success-light);
  color: var(--color-success);
  border: 1px solid var(--color-success);
}

.toast-error {
  background: var(--color-error-light);
  color: var(--color-error);
  border: 1px solid var(--color-error);
}

.toast-info {
  background: var(--color-primary-50);
  color: var(--color-primary-700);
  border: 1px solid var(--color-primary-200);
}

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

/* Loading Spinner */
.spinner {
  width: 1.25rem;
  height: 1.25rem;
  border: 2px solid transparent;
  border-top: 2px solid currentColor;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

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

/* Responsive utilities */
@media (max-width: 768px) {
  .modal {
    margin: var(--space-4);
    max-width: calc(100vw - 2 * var(--space-4));
  }

  .toast {
    right: var(--space-2);
    left: var(--space-2);
    min-width: auto;
    max-width: none;
  }
}