/* ============================================
   LAYOUT - Grundstruktur der Anwendung
   Zwei-Spalten-Layout: Header + Sidebar + Main
   ============================================ */

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

html,
body {
  height: 100%;
  overflow: hidden;
}

body {
  font-family: var(--font-primary);
  font-size: var(--font-size-body);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-main);
}

/* ========== App Container ========== */
.app-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

/* ========== Header ========== */
.app-header {
  height: var(--header-height);
  background-color: var(--color-bg-surface);
  border-bottom: 1px solid var(--color-border-default);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  z-index: 100;
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.header-logo {
  font-size: var(--font-size-h3);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary-1);
}

.header-right {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.header-user {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.header-username {
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
}

.header-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: var(--color-primary-3);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary-1);
  font-weight: var(--font-weight-bold);
}

/* ========== Main Layout (Sidebar + Content) ========== */
.app-main {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ========== Sidebar ========== */
.app-sidebar {
  width: var(--sidebar-width);
  background-color: var(--color-bg-surface);
  border-right: 1px solid var(--color-border-default);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

.sidebar-nav {
  padding: var(--spacing-lg) 0;
}

.nav-list {
  list-style: none;
}

.nav-item {
  margin: 0;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md) var(--spacing-lg);
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-normal);
  cursor: pointer;
  border-left: 3px solid transparent;
}

.nav-link:hover {
  background-color: var(--color-primary-4);
  color: var(--color-primary-1);
}

.nav-link.active {
  background-color: var(--color-primary-4);
  color: var(--color-primary-1);
  border-left-color: var(--color-primary-1);
  font-weight: var(--font-weight-bold);
}

.nav-icon {
  font-size: 20px;
  width: 24px;
  text-align: center;
}

/* ========== Content Area ========== */
.app-content {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-xl);
}

/* ========== View Container ========== */
.view {
  display: none;
}

.view.active {
  display: block;
}

/* ========== Page Header ========== */
.page-header {
  margin-bottom: var(--spacing-xl);
}

.page-title {
  font-size: var(--font-size-h1);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.page-subtitle {
  font-size: var(--font-size-body);
  color: var(--color-text-secondary);
}

/* ========== Content Card ========== */
.content-card {
  background-color: var(--color-bg-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

/* ========== Grid System ========== */
.grid {
  display: grid;
  gap: var(--spacing-lg);
}

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

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

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

/* ========== Responsive ========== */
@media (max-width: 1280px) {
  .grid-4 {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 1024px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .app-sidebar {
    display: none;
  }
  
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }
  
  .header-username {
    display: none;
  }
}