/* ============================================================
   YKS Hızlı Okuma — Design System & Base Styles
   ============================================================ */

/* === CSS CUSTOM PROPERTIES === */
:root {
  /* Colors — Dark Mode Palette */
  --bg-primary: hsl(225, 30%, 6%);
  --bg-secondary: hsl(225, 25%, 10%);
  --bg-tertiary: hsl(225, 22%, 14%);
  --bg-card: hsla(225, 25%, 12%, 0.55);
  --bg-card-hover: hsla(225, 25%, 16%, 0.75);
  --bg-card-solid: hsl(225, 25%, 12%);

  /* Brand Colors */
  --color-primary: hsl(210, 100%, 60%);
  --color-primary-light: hsl(210, 100%, 72%);
  --color-primary-dark: hsl(210, 100%, 45%);
  --color-secondary: hsl(270, 100%, 65%);
  --color-secondary-light: hsl(270, 100%, 78%);
  --color-accent: hsl(175, 80%, 55%);
  --color-accent-light: hsl(175, 80%, 70%);
  --color-warning: hsl(35, 100%, 60%);
  --color-warning-light: hsl(35, 100%, 72%);
  --color-success: hsl(145, 70%, 55%);
  --color-success-light: hsl(145, 70%, 68%);
  --color-danger: hsl(0, 80%, 60%);
  --color-danger-light: hsl(0, 80%, 72%);

  /* Text Colors */
  --text-primary: hsl(220, 15%, 95%);
  --text-secondary: hsl(220, 10%, 70%);
  --text-muted: hsl(220, 8%, 48%);
  --text-inverse: hsl(225, 30%, 6%);

  /* Premium Glows */
  --glow-primary: 0 0 15px hsla(210, 100%, 60%, 0.35), 0 0 30px hsla(210, 100%, 60%, 0.15);
  --glow-secondary: 0 0 15px hsla(270, 100%, 65%, 0.35), 0 0 30px hsla(270, 100%, 65%, 0.15);
  --glow-accent: 0 0 15px hsla(175, 80%, 55%, 0.35), 0 0 30px hsla(175, 80%, 55%, 0.15);
  --glow-success: 0 0 15px hsla(145, 70%, 55%, 0.35), 0 0 30px hsla(145, 70%, 55%, 0.15);
  --glow-warning: 0 0 15px hsla(35, 100%, 60%, 0.35), 0 0 30px hsla(35, 100%, 60%, 0.15);
  --glow-danger: 0 0 15px hsla(0, 80%, 60%, 0.35), 0 0 30px hsla(0, 80%, 60%, 0.15);

  /* Easing curves */
  --ease-elastic-1: cubic-bezier(0.5, 1.25, 0.75, 1.25);
  --ease-elastic-2: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-in-out-back: cubic-bezier(0.68, -0.6, 0.27, 1.55);

  /* Glassmorphism */
  --glass-bg: hsla(225, 25%, 10%, 0.4);
  --glass-bg-strong: hsla(225, 25%, 8%, 0.75);
  --glass-border: hsla(220, 20%, 90%, 0.06);
  --glass-border-hover: hsla(220, 20%, 90%, 0.12);
  --glass-blur: blur(20px);

  /* Typography */
  --font-ui: 'Outfit', 'Plus Jakarta Sans', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-reading: 'Noto Sans', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;

  /* Font Sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.625rem;
  --radius-lg: 0.875rem;
  --radius-xl: 1.25rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px hsla(0, 0%, 0%, 0.3), 0 1px 2px hsla(0, 0%, 0%, 0.2);
  --shadow-md: 0 4px 12px hsla(0, 0%, 0%, 0.35);
  --shadow-lg: 0 8px 28px hsla(0, 0%, 0%, 0.45);
  --shadow-xl: 0 16px 48px hsla(0, 0%, 0%, 0.5);
  --shadow-glow-primary: 0 0 24px hsla(210, 100%, 60%, 0.25);
  --shadow-glow-secondary: 0 0 24px hsla(270, 100%, 65%, 0.25);
  --shadow-glow-accent: 0 0 24px hsla(175, 80%, 55%, 0.25);
  --shadow-glow-success: 0 0 24px hsla(145, 70%, 55%, 0.25);
  --shadow-glow-warning: 0 0 24px hsla(35, 100%, 60%, 0.25);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
  --transition-spring: 350ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Layout */
  --sidebar-width: 260px;
  --sidebar-width-collapsed: 0px;
  --header-height: 0px;
  --content-max-width: 100%;
}


/* === CSS RESET === */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-ui);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, video, canvas, svg {
  display: block;
  max-width: 100%;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  font-weight: 700;
}


/* === BASE TYPOGRAPHY === */
h1 { font-size: var(--text-4xl); font-weight: 800; letter-spacing: -0.02em; }
h2 { font-size: var(--text-2xl); font-weight: 700; letter-spacing: -0.01em; }
h3 { font-size: var(--text-xl); font-weight: 600; }
h4 { font-size: var(--text-lg); font-weight: 600; }

p {
  color: var(--text-secondary);
  line-height: 1.7;
}


/* === SCROLLBAR === */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: hsla(210, 100%, 60%, 0.3);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: hsla(210, 100%, 60%, 0.5);
}

/* Firefox scrollbar */
* {
  scrollbar-width: thin;
  scrollbar-color: hsla(210, 100%, 60%, 0.3) transparent;
}


/* === SELECTION === */
::selection {
  background: hsla(210, 100%, 60%, 0.3);
  color: var(--text-primary);
}


/* === PARTICLE BACKGROUND === */
#particles-bg {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.7;
}


/* === LAYOUT — SIDEBAR === */
#sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--glass-bg-strong);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-right: 1px solid var(--glass-border);
  z-index: 100;
  display: flex;
  flex-direction: column;
  padding: var(--space-6) 0;
  transition: transform var(--transition-base), left var(--transition-base);
  overflow-y: auto;
  overflow-x: hidden;
}

#sidebar.collapsed {
  transform: translateX(-100%);
}

.sidebar-header {
  padding: 0 var(--space-6) var(--space-6);
  border-bottom: 1px solid var(--glass-border);
  margin-bottom: var(--space-4);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.logo-icon {
  flex-shrink: 0;
}

.logo-text {
  font-size: var(--text-xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.logo-accent {
  font-weight: 600;
}

.logo-subtitle {
  font-size: var(--text-xs);
  color: var(--text-muted);
  margin-top: var(--space-1);
  padding-left: calc(32px + var(--space-3));
}

/* Navigation Menu */
.nav-menu {
  flex: 1;
  padding: 0 var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  transition: transform 0.3s cubic-bezier(0.25, 0.8, 0.25, 1), color 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
  position: relative;
  font-size: var(--text-sm);
  font-weight: 500;
  will-change: transform, background, color;
}

.nav-link:hover {
  color: var(--text-primary);
  background: hsla(210, 100%, 60%, 0.08);
  transform: translate3d(6px, 0, 0);
}

.nav-link:hover .nav-icon {
  transform: scale(1.15) rotate(-3deg);
  color: var(--color-primary-light);
}

.nav-icon {
  transition: transform 0.2s ease, color 0.2s ease;
}

.nav-link.active {
  color: var(--color-primary);
  background: hsla(210, 100%, 60%, 0.12);
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.08);
}

.nav-link.active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 60%;
  background: linear-gradient(180deg, var(--color-primary), var(--color-accent));
  border-radius: var(--radius-full);
  box-shadow: 0 0 10px var(--color-primary);
}

.nav-icon {
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.nav-text {
  white-space: nowrap;
}


/* === POMODORO MINI WIDGET === */
.pomodoro-mini-widget {
  margin: auto var(--space-4) var(--space-2);
  padding: var(--space-4);
  background: hsla(210, 100%, 60%, 0.06);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  text-align: center;
}

.pomodoro-mini-header {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.pomodoro-mini-time {
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.05em;
  margin-bottom: var(--space-3);
}

.pomodoro-mini-controls {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
}

.pomodoro-mini-btn {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background: hsla(210, 100%, 60%, 0.15);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-sm);
  transition: all var(--transition-fast);
  border: 1px solid transparent;
}

.pomodoro-mini-btn:hover {
  background: hsla(210, 100%, 60%, 0.25);
  border-color: var(--color-primary);
  transform: scale(1.1);
}


/* === MOBILE MENU TOGGLE === */
.menu-toggle {
  display: none;
  position: fixed;
  top: var(--space-4);
  left: var(--space-4);
  z-index: 200;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: var(--glass-bg-strong);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  padding: 8px;
}

.menu-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text-primary);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.menu-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.menu-toggle.active span:nth-child(2) { opacity: 0; }
.menu-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }


/* === SIDEBAR OVERLAY (Mobile) === */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: hsla(0, 0%, 0%, 0.5);
  z-index: 90;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.sidebar-overlay.visible {
  display: block;
  opacity: 1;
}


/* === MAIN CONTENT === */
#main-content {
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  position: relative;
  z-index: 1;
  transition: margin-left var(--transition-base);
}

#main-content.expanded {
  margin-left: 0;
}

.page-container {
  position: relative;
  padding: var(--space-8) var(--space-8) var(--space-16);
  max-width: var(--content-max-width);
  margin: 0 auto;
}


/* === PAGE TRANSITIONS === */
.page-container {
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.page-exit {
  opacity: 0;
  transform: translateY(8px);
}

.page-enter {
  animation: pageEnter 300ms ease forwards;
}

@keyframes pageEnter {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}


/* === TOAST NOTIFICATIONS === */
.toast-container {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  pointer-events: none;
}

.toast {
  padding: var(--space-4) var(--space-6);
  background: var(--glass-bg-strong);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  color: var(--text-primary);
  font-size: var(--text-sm);
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  pointer-events: auto;
  animation: toastIn 300ms ease forwards;
  max-width: 360px;
}

.toast.toast-success { border-left: 3px solid var(--color-success); }
.toast.toast-error   { border-left: 3px solid var(--color-danger); }
.toast.toast-info    { border-left: 3px solid var(--color-primary); }
.toast.toast-warning { border-left: 3px solid var(--color-warning); }

.toast.toast-out {
  animation: toastOut 250ms ease forwards;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateX(40px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes toastOut {
  from { opacity: 1; transform: translateX(0); }
  to   { opacity: 0; transform: translateX(40px); }
}


/* === UTILITY CLASSES === */
.text-center { text-align: center; }
.text-left   { text-align: left; }
.text-right  { text-align: right; }

.text-primary   { color: var(--color-primary); }
.text-secondary { color: var(--color-secondary); }
.text-accent    { color: var(--color-accent); }
.text-success   { color: var(--color-success); }
.text-warning   { color: var(--color-warning); }
.text-danger    { color: var(--color-danger); }
.text-muted     { color: var(--text-muted); }

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

.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }

.w-full { width: 100%; }
.hidden { display: none !important; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}


/* === RESPONSIVE — TABLET === */
@media (max-width: 1024px) {
  :root {
    --sidebar-width: 220px;
  }
  .page-container {
    padding: var(--space-6);
  }
}


/* === RESPONSIVE — MOBILE === */
@media (max-width: 768px) {
  .menu-toggle {
    display: flex;
  }

  #sidebar {
    transform: translateX(-100%);
    width: 280px;
  }

  #sidebar.open {
    transform: translateX(0);
  }

  #main-content {
    margin-left: 0;
  }

  .page-container {
    padding: var(--space-4);
    padding-top: calc(var(--space-4) + 56px); /* space for menu toggle */
  }

  .logo-subtitle {
    display: none;
  }
}

@media (max-width: 480px) {
  :root {
    --text-4xl: 1.75rem;
    --text-3xl: 1.5rem;
    --text-2xl: 1.25rem;
  }
  
  .page-container {
    padding: var(--space-3);
    padding-top: calc(var(--space-3) + 56px);
  }

  .toast-container {
    left: var(--space-3);
    right: var(--space-3);
  }
  .toast {
    max-width: 100%;
  }
}

/* Sidebar Collapse & Expand Buttons */
.sidebar-collapse-btn:hover {
  color: var(--color-primary) !important;
}
.sidebar-expand-btn:hover {
  transform: scale(1.05);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow-primary);
}

/* === NE İŞE YARAR HELP WIDGET & MODAL === */
.help-trigger-btn {
  position: absolute;
  top: 24px;
  right: 24px;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--glass-bg-strong);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-full);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-ui);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-primary);
  box-shadow: var(--shadow-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.help-trigger-btn:hover {
  background: hsla(210, 100%, 60%, 0.12);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow-primary);
}

.help-trigger-btn svg {
  stroke: var(--color-primary);
  animation: pulse 2s infinite;
}

.help-modal-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.help-modal-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-2);
}

.help-modal-icon {
  font-size: 2.2rem;
  background: hsla(210, 100%, 60%, 0.1);
  border-radius: var(--radius-lg);
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid hsla(210, 100%, 60%, 0.2);
}

.help-modal-title h3 {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--text-primary);
  margin: 0;
}

.help-modal-title p {
  font-size: var(--text-xs);
  color: var(--text-muted);
  margin: 0;
}

.help-modal-card {
  background: hsla(210, 100%, 60%, 0.04);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.help-modal-card.accent {
  background: hsla(145, 70%, 55%, 0.04);
  border-color: hsla(145, 70%, 55%, 0.2);
}

.help-modal-card-title {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--text-primary);
}

.help-modal-card-title.accent-text {
  color: var(--color-success);
}

.help-modal-card p {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: 1.5;
  margin: 0;
}

.help-modal-list {
  padding-left: var(--space-5);
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.help-modal-list li {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: 1.4;
  list-style-type: square;
}

.help-modal-list li::marker {
  color: var(--color-primary);
}

@media (max-width: 768px) {
  .help-trigger-btn {
    top: 12px;
    right: 12px;
  }

  /* Mobilde sayfa basligi sarinca mutlak konumlu "Ne İşe Yarar?"
     butonunun altina girip uzerine biniyordu; basliga yer ayrildi. */
  .exercise-header {
    padding-top: 56px;
  }
}

/* === DYNAMIC CYBERPUNK BACKGROUND EFFECT === */
body {
  position: relative;
  background: #060913 !important;
}

/* 1. Animated Radial Mesh Gradient Background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -2;
  pointer-events: none;
  background: radial-gradient(
    circle at 50% 50%,
    hsl(225, 30%, 8%) 0%,
    hsl(225, 32%, 5%) 50%,
    hsl(225, 35%, 3%) 100%
  );
  background-size: 200% 200%;
  animation: dynamicMeshGradient 25s ease infinite;
}

/* 2. Slowly Scrolling Cyber Tech Grid Pattern */
body::after {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  pointer-events: none;
  opacity: 0.04;
  background-image: 
    linear-gradient(rgba(0, 240, 255, 0.15) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 240, 255, 0.15) 1px, transparent 1px);
  background-size: 50px 50px;
  background-position: center;
  animation: cyberGridScrolling 30s linear infinite;
}

@keyframes dynamicMeshGradient {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}

@keyframes cyberGridScrolling {
  0% {
    background-position: 0px 0px;
  }
  100% {
    background-position: 50px 50px;
  }
}