/* ===================================
   DESIGN SYSTEM - Photographer Portfolio
   Monochromatic Theme, Mobile-First
   =================================== */

/* CSS Variables - Grayscale Color Palette */
:root {
  /* Grayscale Color Palette */
  --color-black: #000000;
  --color-off-black: #1a1a1a;
  --color-dark-gray: #333333;
  --color-medium-gray: #666666;
  --color-light-gray: #999999;
  --color-silver: #cccccc;
  --color-off-white: #e8e8e8;
  --color-bg-light: #f5f5f5;
  --color-white: #ffffff;
  --color-charcoal: #2d2d2d;
  --color-pearl: #e8e8e8;

  /* Status Color Palette */
  --color-error: #cc0000;
  --color-success: #009933;
  --color-warning: #ff9900;
  --color-alert-bg: #fff3f3;
  --color-alert-border: #ffcccc;
  --color-alert-text: #990000;

  /* Typography Scale */
  --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  /* Mobile Typography */
  --font-size-h1-mobile: 48px;
  --font-size-h2-mobile: 36px;
  --font-size-h3-mobile: 20px;
  --font-size-h4-mobile: 18px;
  --font-size-body-large-mobile: 16px;
  --font-size-body-mobile: 15px;
  --font-size-small-mobile: 13px;

  /* Desktop Typography */
  --font-size-h1-desktop: 64px;
  --font-size-h2-desktop: 48px;
  --font-size-h3-desktop: 24px;
  --font-size-h4-desktop: 20px;
  --font-size-body-large-desktop: 18px;
  --font-size-body-desktop: 16px;
  --font-size-small-desktop: 14px;

  /* Spacing Scale (8px base) */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-xxl: 64px;
  --spacing-xxxl: 96px;

  /* Border Radius */
  --radius-sm: 2px;
  --radius-md: 4px;
  --radius-lg: 8px;
  --radius-pill: 20px;
  --radius-circle: 50%;

  /* Transitions */
  --transition-fast: 0.15s ease-out;
  --transition-normal: 0.2s ease-out;
  --transition-slow: 0.3s cubic-bezier(0.4, 0, 0.2, 1);

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.15);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.25);
}

/* Reset & Base Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-body-mobile);
  line-height: 1.6;
  color: var(--color-black);
  background-color: var(--color-white);
  min-height: 100vh;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-black);
  text-decoration: none;
  transition: color var(--transition-fast);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-black);
}

h1 {
  font-size: var(--font-size-h1-mobile);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--font-size-h2-mobile);
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.2;
}

h3 {
  font-size: var(--font-size-h3-mobile);
  font-weight: 600;
  line-height: 1.3;
}

h4 {
  font-size: var(--font-size-h4-mobile);
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: 0.02em;
}

p {
  line-height: 1.6;
  color: var(--color-dark-gray);
}

/* Container */
.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--spacing-sm);
}

/* Section Spacing */
section {
  padding: var(--spacing-xl) 0;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-family-base);
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-normal);
  text-align: center;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--color-black);
  color: var(--color-white);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-body-large-mobile);
  height: 48px;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background-color: var(--color-off-black);
  transform: scale(1.02);
  box-shadow: var(--shadow-md);
}

.btn-primary:active {
  transform: scale(0.98);
  box-shadow: var(--shadow-sm);
}

.btn-secondary {
  background-color: transparent;
  color: var(--color-black);
  border: 2px solid var(--color-black);
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: var(--font-size-body-mobile);
  height: 44px;
}

.btn-secondary:hover {
  background-color: var(--color-black);
  color: var(--color-white);
  transform: scale(1.02);
}

/* Form Elements */
input[type="text"],
input[type="email"],
textarea,
select {
  width: 100%;
  height: 48px;
  padding: 12px var(--spacing-sm);
  border: 1px solid var(--color-silver);
  border-radius: var(--radius-md);
  font-size: 16px;
  font-family: var(--font-family-base);
  color: var(--color-black);
  background-color: var(--color-white);
  transition: border-color var(--transition-fast),
              box-shadow var(--transition-fast);
}

input[type="text"]:focus,
input[type="email"]:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--color-black);
  box-shadow: 0 0 0 2px var(--color-black);
}

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

::placeholder {
  color: var(--color-light-gray);
}

/* Focus States */
:focus-visible {
  outline: 2px solid var(--color-black);
  outline-offset: 2px;
}

/* ===================================
   Navigation
   =================================== */
.navigation {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-off-white);
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.95);
}

.navigation__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.navigation__logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--color-black);
}

.navigation__links {
  display: none;
  gap: var(--spacing-sm);
}

.navigation__link {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 16px;
  font-weight: 500;
  color: var(--color-black);
  text-decoration: none;
}

.navigation__link:hover,
.navigation__link--active {
  text-decoration: underline;
  font-weight: 600;
}

/* Mobile Menu Button */
.navigation__menu-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.navigation__menu-icon {
  width: 24px;
  height: 24px;
  fill: var(--color-black);
}

/* ===================================
   Photo Cards
   =================================== */
.photo-card {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  background-color: var(--color-white);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-slow);
  cursor: pointer;
}

.photo-card:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
}

.photo-card__badge {
  position: absolute;
  top: var(--spacing-xs);
  left: var(--spacing-xs);
  background-color: rgba(0, 0, 0, 0.7);
  color: var(--color-white);
  font-size: 12px;
  font-weight: 600;
  padding: 4px var(--spacing-xs);
  border-radius: var(--radius-sm);
  z-index: 10;
}

.photo-card__image {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
}

.photo-card__title {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 48px;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.7), transparent);
  color: var(--color-white);
  font-size: 14px;
  font-weight: 600;
  padding: var(--spacing-xs) var(--spacing-sm);
  display: flex;
  align-items: flex-end;
}

/* ===================================
   Photo Grid
   =================================== */
.photo-grid {
  display: grid;
  gap: var(--spacing-sm);
}

/* Mobile first: Single column */
.photo-grid--2 {
  grid-template-columns: 1fr;
}

/* Tablet: 2 columns */
@media (min-width: 640px) {
  .photo-grid--2 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Desktop: 3 columns */
@media (min-width: 1024px) {
  .photo-grid--2 {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ===================================
   Mobile Menu
   =================================== */
.mobile-menu {
  position: fixed;
  top: 64px;
  right: 0;
  bottom: 0;
  left: 0;
  background-color: var(--color-white);
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  z-index: 999;
}

.mobile-menu--open {
  transform: translateX(0);
}

.mobile-menu__container {
  position: relative;
  padding: var(--spacing-lg);
  height: 100%;
}

.mobile-menu__close {
  position: absolute;
  top: var(--spacing-md);
  right: var(--spacing-md);
  width: 48px;
  height: 48px;
  background: none;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

.mobile-menu__links {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-xl);
}

.mobile-menu__link {
  font-size: 18px;
  font-weight: 500;
  color: var(--color-black);
  text-decoration: none;
  padding: 14px 16px;
  border-bottom: 1px solid var(--color-bg-light);
  min-height: 48px;
  display: flex;
  align-items: center;
  transition: background-color var(--transition-fast);
}

.mobile-menu__link:hover,
.mobile-menu__link:focus {
  background-color: var(--color-bg-light);
}

.mobile-menu__link:active {
  background-color: var(--color-off-white);
}

/* ===================================
   Footer
   =================================== */
.footer {
  background-color: var(--color-black);
  color: var(--color-white);
  padding: var(--spacing-xl) 0;
  margin-top: var(--spacing-xxl);
}

.footer__copyright {
  font-size: 14px;
  opacity: 0.7;
  text-align: center;
}

/* ===================================
   Utility Classes
   =================================== */
.text-center { text-align: center; }
.mt-xl { margin-top: var(--spacing-xl); }
.mb-xl { margin-bottom: var(--spacing-xl); }
.mb-md { margin-bottom: var(--spacing-md); }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===================================
   Tablet (640px+)
   =================================== */
@media (min-width: 640px) {
  body {
    font-size: var(--font-size-body-desktop);
  }

  h1 { font-size: var(--font-size-h1-desktop); }
  h2 { font-size: var(--font-size-h2-desktop); }
  h3 { font-size: var(--font-size-h3-desktop); }
  h4 { font-size: var(--font-size-h4-desktop); }

  .navigation__links {
    display: flex;
  }

  .navigation__menu-btn {
    display: none;
  }

  .photo-grid--3 {
    grid-template-columns: repeat(3, 1fr);
  }

  .photo-grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ===================================
    Large Desktop (1280px+)
    =================================== */
@media (min-width: 1280px) {
  .photo-grid--4 {
    grid-template-columns: repeat(4, 1fr);
  }

  .container {
    padding: 0 var(--spacing-md);
  }

  .photo-card__title {
    height: 56px;
    font-size: 16px;
    padding: var(--spacing-sm) var(--spacing-md);
  }
}

/* ===================================
   Desktop (1024px+)
   =================================== */
@media (min-width: 1024px) {
  .container {
    max-width: 1280px;
  }

  .btn-primary {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-h4-desktop);
    height: 56px;
  }
}

/* ===================================
    Accessibility
    =================================== */
.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--color-black);
  color: var(--color-white);
  padding: var(--spacing-sm);
  z-index: 9999;
  transition: top 0.2s;
}

.skip-link:focus {
  top: 0;
}

/* ===================================
    Page Transitions
    =================================== */
main {
  animation: pageFadeIn 0.4s ease-out;
}

@keyframes pageFadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Smooth page transition on navigation */
.page-transition {
  transition: opacity 0.3s ease-out, transform 0.3s ease-out;
}

.page-transition.fade-out {
  opacity: 0;
  transform: translateY(10px);
}

/* ===================================
    Mobile (max-width: 768px)
    =================================== */
@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }
}