/* ========================================
   SftKit - Global Styles
   ======================================== */

:root {

  /* ================================
     1. Spacing System
  ================================= */

  /* Base spacing unit */
  --side-margin: 1rem;

  /* Derived spacings */
  --spacing-2xs: calc(var(--side-margin) * 0.125);
  --spacing-xs: calc(var(--side-margin) * 0.25);
  --spacing-sm: calc(var(--side-margin) * 0.5);
  --spacing-sm-plus: calc(var(--side-margin) * 0.75);
  --spacing-md: var(--side-margin);
  --spacing-lg: calc(var(--side-margin) * 1.5);
  --spacing-xl: calc(var(--side-margin) * 2);
  --spacing-2xl: calc(var(--side-margin) * 3);
  --spacing-3xl: calc(var(--side-margin) * 4);

  /* Element Spacing */
  --element-spacing-normal: 12px 16px;
  --spacing-content-dense: calc(var(--side-margin) * 0.3);

  /* ================================
     2. Layout Dimensions
  ================================= */

  --container-width: min(1200px, calc(100% - 4rem));
  --width-page-desktop: 680px;
  --width-page-body: 640px;
  --width-form-max: 480px;
  --width-full: 100%;
  --height-full: 100%;
  --header-height: 60px;

  /* Component Dimensions */
  --button-height: 48px;
  --input-height: 48px;
  --component-size-theme-btn: 30px;
  --component-size-theme-icon: 16px;
  --component-size-logo-icon: 28px;
  --grid-cell-size: 32px;

  /* ================================
     3. Typography & Shapes
  ================================= */

  /* Font Family */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;

  /* Text Sizes */
  --text-size-micro: 0.625rem;
  --text-size-helper: 0.75rem;
  --text-size-sm: 0.875rem;
  --text-size-body: 0.9375rem;
  --text-size-md: 1rem;
  --text-size-navigation: 0.875rem;
  --text-size-section-title: 1.25rem;
  --text-size-page-title: clamp(1.75rem, 4vw, 2.5rem);
  --text-size-hero-title: clamp(2rem, 5vw, 3.5rem);
  --text-size-hero-subtitle: clamp(0.875rem, 1.8vw, 1.0625rem);
  --text-size-logo: 1.125rem;
  --text-size-badge: 0.75rem;
  --text-size-footer: 0.75rem;
  --text-size-label: 0.8125rem;
  --text-size-form-success-title: 1.375rem;

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

  /* Line Heights */
  --line-height-base: 1.5;
  --line-height-relaxed: 1.7;
  --line-height-body: 1.8;
  --line-height-tight: 1.15;

  /* Letter Spacing */
  --tracking-tight: -0.03em;
  --tracking-snug: -0.02em;
  --tracking-wide: 0.02em;

  /* Corner Rounding */
  --corner-subtle: 0.25rem;
  --corner-input: 0.5rem;
  --corner-button: 0.5rem;
  --corner-card: 0.75rem;
  --corner-pill: 100px;
  --corner-toggle: 0.375rem;

  /* ================================
     4. Motion & Effects
  ================================= */

  --transition-fast: 0.2s;
  --transition-base: 0.3s;
  --transition-easing: cubic-bezier(0.33, 1, 0.68, 1);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 0.25rem 0.375rem rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);

  /* Transforms */
  --translate-hover-nudge: -1px;

  /* ================================
     5. Theme Palettes
  ================================= */

  /* Hint native UI to support both themes */
  color-scheme: light dark;

  /* ---------- Light palette (source values) ---------- */
  --light-bg-primary: #fafafa;
  --light-text-primary: #111111;
  --light-text-secondary: #666666;
  --light-text-muted: #999999;
  --light-text-mid: #444444;
  --light-text-label: #333333;
  --light-nav-text: #555555;
  --light-btn-bg: #111111;
  --light-btn-bg-hover: #333333;
  --light-btn-text: #ffffff;
  --light-border: rgba(0, 0, 0, 0.06);
  --light-input-border: rgba(0, 0, 0, 0.12);
  --light-input-bg: #ffffff;
  --light-input-focus-shadow: rgba(0, 0, 0, 0.06);
  --light-badge-bg: rgba(255, 255, 255, 0.8);
  --light-badge-border: rgba(0, 0, 0, 0.08);
  --light-grid: rgba(0, 0, 0, 0.04);

  /* ---------- Dark palette (source values) ---------- */
  --dark-bg-primary: #0f1117;
  --dark-text-primary: #f0f0f0;
  --dark-text-secondary: #9ca3af;
  --dark-text-muted: #6b7280;
  --dark-text-mid: #d1d5db;
  --dark-text-label: #d1d5db;
  --dark-nav-text: #9ca3af;
  --dark-btn-bg: #f0f0f0;
  --dark-btn-bg-hover: #d1d5db;
  --dark-btn-text: #0f1117;
  --dark-border: rgba(255, 255, 255, 0.08);
  --dark-input-border: rgba(255, 255, 255, 0.12);
  --dark-input-bg: rgba(255, 255, 255, 0.05);
  --dark-input-focus-shadow: rgba(255, 255, 255, 0.06);
  --dark-badge-bg: rgba(255, 255, 255, 0.06);
  --dark-badge-border: rgba(255, 255, 255, 0.1);
  --dark-grid: rgba(255, 255, 255, 0.04);

  /* ---------- Status & Feedback Colors ---------- */
  --status-success: #38B2AC;
  --status-error: #E53E3E;
  --status-warning: #ED8936;
  --status-info: #4299E1;

  /* ---------- Utility Colors ---------- */
  --color-white: #ffffff;
  --color-black: #000000;
  --color-disabled: #8A8A8A;

  /* ================================
     6. Active Theme Aliases (default: dark)
  ================================= */

  --bg-primary: var(--dark-bg-primary);
  --text-primary: var(--dark-text-primary);
  --text-secondary: var(--dark-text-secondary);
  --text-muted: var(--dark-text-muted);
  --text-mid: var(--dark-text-mid);
  --text-label: var(--dark-text-label);
  --nav-text: var(--dark-nav-text);
  --btn-bg: var(--dark-btn-bg);
  --btn-bg-hover: var(--dark-btn-bg-hover);
  --btn-text: var(--dark-btn-text);
  --border-color: var(--dark-border);
  --input-border: var(--dark-input-border);
  --input-bg: var(--dark-input-bg);
  --input-focus-shadow: var(--dark-input-focus-shadow);
  --badge-bg: var(--dark-badge-bg);
  --badge-border: var(--dark-badge-border);
  --grid-color: var(--dark-grid);
}

/* ========================================
   Theme: Light (explicit)
   ======================================== */

[data-theme="light"] {
  --bg-primary: var(--light-bg-primary);
  --text-primary: var(--light-text-primary);
  --text-secondary: var(--light-text-secondary);
  --text-muted: var(--light-text-muted);
  --text-mid: var(--light-text-mid);
  --text-label: var(--light-text-label);
  --nav-text: var(--light-nav-text);
  --btn-bg: var(--light-btn-bg);
  --btn-bg-hover: var(--light-btn-bg-hover);
  --btn-text: var(--light-btn-text);
  --border-color: var(--light-border);
  --input-border: var(--light-input-border);
  --input-bg: var(--light-input-bg);
  --input-focus-shadow: var(--light-input-focus-shadow);
  --badge-bg: var(--light-badge-bg);
  --badge-border: var(--light-badge-border);
  --grid-color: var(--light-grid);
}

/* ========================================
   Theme: Dark (explicit)
   ======================================== */

[data-theme="dark"] {
  --bg-primary: var(--dark-bg-primary);
  --text-primary: var(--dark-text-primary);
  --text-secondary: var(--dark-text-secondary);
  --text-muted: var(--dark-text-muted);
  --text-mid: var(--dark-text-mid);
  --text-label: var(--dark-text-label);
  --nav-text: var(--dark-nav-text);
  --btn-bg: var(--dark-btn-bg);
  --btn-bg-hover: var(--dark-btn-bg-hover);
  --btn-text: var(--dark-btn-text);
  --border-color: var(--dark-border);
  --input-border: var(--dark-input-border);
  --input-bg: var(--dark-input-bg);
  --input-focus-shadow: var(--dark-input-focus-shadow);
  --badge-bg: var(--dark-badge-bg);
  --badge-border: var(--dark-badge-border);
  --grid-color: var(--dark-grid);
}

/* ========================================
   Reset & Base
   ======================================== */

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

html, body {
  height: var(--height-full);
}

body {
  font-family: var(--font-primary);
  color: var(--text-primary);
  background: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background var(--transition-base), color var(--transition-base);
}

/* Grid notebook background */
.grid-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--width-full);
  height: var(--height-full);
  pointer-events: none;
  z-index: 0;
  background-image:
    linear-gradient(var(--grid-color) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-color) 1px, transparent 1px);
  background-size: var(--grid-cell-size) var(--grid-cell-size);
}

/* ========================================
   Page Wrapper (single viewport)
   ======================================== */

.page-wrapper {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  height: 100dvh;
  min-height: 100dvh;
  overflow: hidden;
}

/* ========================================
   Header
   ======================================== */

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-lg) var(--spacing-xl);
  flex-shrink: 0;
}

.logo {
  display: flex;
  align-items: center;
  text-decoration: none;
}

.logo-icon {
  height: 80px;
  width: auto;
  object-fit: contain;
  transition: filter var(--transition-base);
}

[data-theme="dark"] .logo-icon {
  filter: invert(1) brightness(2);
}

/* ========================================
   Desktop Nav (inline)
   ======================================== */

.nav-desktop {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.nav-link {
  text-decoration: none;
  color: var(--text-primary);
  font-weight: var(--font-medium);
  font-size: var(--text-size-navigation);
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--text-secondary);
}

.theme-toggle-inline {
  display: flex;
  align-items: center;
  gap: var(--spacing-2xs);
  background: var(--badge-bg);
  border: 1px solid var(--badge-border);
  border-radius: var(--corner-input);
  padding: var(--spacing-xs);
}

.theme-toggle-inline .theme-btn {
  flex: unset;
  flex-direction: row;
  width: var(--component-size-theme-btn);
  height: var(--component-size-theme-btn);
  padding: 0;
  border: none;
  border-radius: var(--corner-toggle);
  color: var(--text-primary);
}

.theme-toggle-inline .theme-btn span {
  display: none;
}

.theme-toggle-inline .theme-btn-active {
  background: var(--border-color);
  border: none;
}

/* ========================================
   Gear Button (mobile only)
   ======================================== */

.gear-btn {
  display: none;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  border-radius: var(--corner-input);
  cursor: pointer;
  color: var(--text-primary);
  transition: color var(--transition-fast);
}

.gear-btn:hover {
  color: var(--text-secondary);
}

.gear-icon {
  width: 22px;
  height: 22px;
  transition: transform 0.5s var(--transition-easing);
}

.gear-btn.is-active .gear-icon {
  transform: rotate(90deg);
}

/* ========================================
   Settings Panel + Overlay
   ======================================== */

.panel-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0);
  z-index: 90;
  pointer-events: none;
  transition: background 0.4s var(--transition-easing);
}

.panel-overlay.is-visible {
  background: rgba(0, 0, 0, 0.3);
  pointer-events: auto;
}

.settings-panel {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 280px;
  max-width: 85vw;
  background: var(--bg-primary);
  border-left: 1px solid var(--border-color);
  z-index: 100;
  transform: translateX(100%);
  transition: transform 0.4s var(--transition-easing);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

.settings-panel.is-open {
  transform: translateX(0);
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-lg) var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
  flex-shrink: 0;
}

.panel-title {
  font-size: var(--text-size-body);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
}

.panel-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: none;
  background: transparent;
  border-radius: var(--corner-toggle);
  cursor: pointer;
  color: var(--text-muted);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.panel-close:hover {
  color: var(--text-primary);
  background: var(--border-color);
}

.panel-close svg {
  width: 18px;
  height: 18px;
}

.panel-section-label {
  display: block;
  font-size: var(--text-size-helper);
  font-weight: var(--font-semibold);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--spacing-sm-plus);
}

.panel-nav {
  padding: var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
}

.panel-link {
  display: flex;
  align-items: center;
  padding: var(--spacing-sm-plus) var(--spacing-md);
  font-size: var(--text-size-sm);
  font-weight: var(--font-medium);
  color: var(--text-primary);
  text-decoration: none;
  border-radius: var(--corner-input);
  transition: background var(--transition-fast);
}

.panel-link:hover {
  background: var(--border-color);
}

.panel-theme {
  padding: var(--spacing-xl);
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 0 var(--spacing-lg);
}

.hero-title {
  font-size: var(--text-size-hero-title);
  font-weight: var(--font-extrabold);
  line-height: var(--line-height-tight);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
  max-width: var(--width-page-desktop);
}

.hero-subtitle {
  margin-top: var(--spacing-lg);
  font-size: var(--text-size-hero-subtitle);
  font-weight: var(--font-regular);
  line-height: var(--line-height-relaxed);
  color: var(--text-secondary);
  max-width: 500px;
}

.hero-badges {
  display: flex;
  gap: var(--spacing-sm-plus);
  margin-top: var(--spacing-xl);
  flex-wrap: wrap;
  justify-content: center;
}

.badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: var(--text-size-badge);
  font-weight: var(--font-semibold);
  color: var(--text-mid);
  background: var(--badge-bg);
  border: 1px solid var(--badge-border);
  border-radius: var(--corner-pill);
  letter-spacing: var(--tracking-wide);
}

.hero-cta {
  margin-top: var(--spacing-xl);
  display: inline-block;
  padding: var(--element-spacing-normal);
  font-size: var(--text-size-sm);
  font-weight: var(--font-semibold);
  color: var(--btn-text);
  background: var(--btn-bg);
  border: none;
  border-radius: var(--corner-button);
  text-decoration: none;
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.hero-cta:hover {
  background: var(--btn-bg-hover);
  transform: translateY(var(--translate-hover-nudge));
}

/* ========================================
   Footer
   ======================================== */

.footer {
  flex-shrink: 0;
  padding: var(--spacing-lg) var(--spacing-xl);
}

.footer-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border-color);
  padding-top: var(--spacing-lg);
}

.footer-copy {
  font-size: var(--text-size-footer);
  color: var(--text-primary);
  font-weight: var(--font-regular);
}

.footer-links {
  display: flex;
  gap: var(--spacing-lg);
}

.footer-links a {
  font-size: var(--text-size-footer);
  color: var(--text-primary);
  text-decoration: none;
  font-weight: var(--font-regular);
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--text-secondary);
}

/* ========================================
   Sub-pages Layout
   ======================================== */

.page-scrollable {
  overflow-y: auto;
}

.page-scrollable .hero {
  flex: unset;
}

.page-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--spacing-3xl) var(--spacing-lg) var(--spacing-xl);
}

.page-content h1 {
  font-size: var(--text-size-page-title);
  font-weight: var(--font-extrabold);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.page-content .page-updated {
  font-size: var(--text-size-label);
  color: var(--text-muted);
  margin-bottom: var(--spacing-xl);
}

.page-body {
  max-width: var(--width-page-body);
  width: var(--width-full);
  line-height: var(--line-height-body);
  font-size: var(--text-size-body);
  color: var(--text-mid);
}

.page-body h2 {
  font-size: var(--text-size-section-title);
  font-weight: var(--font-bold);
  color: var(--text-primary);
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-sm-plus);
}

.page-body p {
  margin-bottom: var(--spacing-md);
}

.page-body ul {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-lg);
}

.page-body li {
  margin-bottom: var(--spacing-sm);
}

.page-body a {
  color: var(--text-primary);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ========================================
   Support / Contact Form
   ======================================== */

.contact-form {
  max-width: var(--width-form-max);
  width: var(--width-full);
  margin-top: var(--spacing-xl);
}

.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  font-size: var(--text-size-label);
  font-weight: var(--font-semibold);
  color: var(--text-label);
  margin-bottom: var(--spacing-xs);
}

.form-input,
.form-textarea {
  width: var(--width-full);
  padding: var(--element-spacing-normal);
  font-size: var(--text-size-sm);
  font-family: var(--font-primary);
  color: var(--text-primary);
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: var(--corner-input);
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--text-primary);
  box-shadow: 0 0 0 3px var(--input-focus-shadow);
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

.form-submit {
  display: inline-block;
  padding: var(--element-spacing-normal);
  font-size: var(--text-size-sm);
  font-weight: var(--font-semibold);
  font-family: var(--font-primary);
  color: var(--btn-text);
  background: var(--btn-bg);
  border: none;
  border-radius: var(--corner-button);
  cursor: pointer;
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.form-submit:hover {
  background: var(--btn-bg-hover);
  transform: translateY(var(--translate-hover-nudge));
}

.form-success {
  display: none;
  text-align: center;
  padding: var(--spacing-xl) 0;
}

.form-success h2 {
  font-size: var(--text-size-form-success-title);
  font-weight: var(--font-bold);
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.form-success p {
  font-size: var(--text-size-body);
  color: var(--text-secondary);
}

/* ========================================
   Support Email Button
   ======================================== */

.support-email-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-xl);
  padding: var(--element-spacing-normal);
  font-size: var(--text-size-sm);
  font-weight: var(--font-medium);
  font-family: var(--font-primary);
  color: var(--text-primary);
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: var(--corner-button);
  text-decoration: none;
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.support-email-btn:hover {
  border-color: var(--text-muted);
  background: var(--border-color);
}

.support-email-btn svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

/* ========================================
   Theme Toggle
   ======================================== */

.theme-toggle {
  display: flex;
  gap: var(--spacing-xs);
}

.theme-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm-plus) var(--spacing-sm);
  border: 1px solid var(--border-color);
  background: transparent;
  border-radius: var(--corner-input);
  cursor: pointer;
  color: var(--text-muted);
  transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast);
}

.theme-btn:hover {
  color: var(--text-primary);
  border-color: var(--text-muted);
}

.theme-btn-active {
  color: var(--text-primary);
  background: var(--border-color);
  border-color: var(--text-muted);
}

.theme-btn svg {
  width: var(--component-size-theme-icon);
  height: var(--component-size-theme-icon);
}

.theme-btn span {
  font-size: var(--text-size-micro);
  font-weight: var(--font-medium);
  font-family: var(--font-primary);
}

/* ========================================
   Responsive
   ======================================== */

@media (max-width: 764px) {
  .nav-desktop {
    display: none;
  }

  .gear-btn {
    display: flex;
  }

  .header {
    padding: var(--spacing-md) var(--spacing-lg);
  }

  .footer {
    padding: var(--spacing-md) var(--spacing-lg);
  }

  .footer-content {
    flex-direction: column;
    gap: var(--spacing-sm);
    text-align: center;
  }

  .footer-links {
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    justify-content: center;
  }

  .logo-icon {
    height: 56px;
  }

  .page-content {
    padding: var(--spacing-xl) var(--spacing-lg) var(--spacing-xl);
  }

  .hero-badges {
    gap: var(--spacing-sm);
  }
}