/* ==================== CSS-Variablen ==================== */
:root {
  /* Farben */
  --color-primary: #000000;
  --color-secondary: #3d1f6a;
  --color-accent: #9d4edd;
  --color-border: #6a4a8a;
  --color-text: #ffffff;
  --color-text-light: #8d8d8d;
  --color-delete: #ff4d4d;
  --color-background: #2c2c2c;

  /* Typografie */
  --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-family-mono: "Courier New", monospace;
  --font-size-base: clamp(0.875rem, 2.5vw, 1rem);
  --font-size-sm: clamp(0.75rem, 2vw, 0.875rem);
  --font-size-lg: clamp(1rem, 2.8vw, 1.125rem);
  --font-size-xl: clamp(1.25rem, 3.5vw, 1.5rem);
  --font-size-2xl: clamp(1.5rem, 4vw, 2rem);
  --font-size-3xl: clamp(2rem, 5vw, 3rem);
  --font-size-4xl: clamp(2.5rem, 6vw, 4rem);
  --font-size-5xl: clamp(3rem, 8vw, 5rem);
  --line-height-base: 1.6;
  --line-height-heading: 1.2;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-bold: 700;

  /* Abstände */
  --spacing-xs: clamp(0.2rem, 0.5vw, 0.25rem);
  --spacing-sm: clamp(0.375rem, 1vw, 0.5rem);
  --spacing-md: clamp(0.75rem, 1.5vw, 1rem);
  --spacing-lg: clamp(1rem, 2vw, 1.5rem);
  --spacing-xl: clamp(1.5rem, 2.5vw, 2rem);
  --spacing-2xl: clamp(2rem, 3vw, 3rem);
  --spacing-3xl: clamp(2.5rem, 4vw, 4rem);

  /* Breakpoints (für Media Queries) */
  --breakpoint-sm: 576px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 992px;
  --breakpoint-xl: 1200px;

  /* Größen */
  --container-width: 1200px;
  --container-padding: var(--spacing-md);
  --border-radius: 0.25rem;
  --border-radius-md: 12px;
  --border-radius-lg: 15px;
  --border-radius-full: 1000px;
  --border-width: 1px;

  /* Übergänge */
  --transition-speed: 150ms;
  --transition-timing: ease-in-out;
}

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

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--color-text);
  background-color: var(--color-background);
}

/* ==================== Typografie ==================== */
h1, h2, h3, h4, h5, h6 {
  line-height: var(--line-height-heading);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }
h4, h5, h6 { font-size: var(--font-size-lg); }

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

a {
  color: var(--color-text);
  text-decoration: none;
  transition: color var(--transition-speed) var(--transition-timing);
}

a:hover {
  text-decoration: underline;
}

code {
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  background-color: var(--color-background);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
}

/* ==================== Listen ==================== */
ul, ol {
  margin-bottom: var(--spacing-md);
  margin-left: var(--spacing-lg);
}

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

/* ==================== Formulare ==================== */
input,
textarea,
select,
button {
  font: inherit;
  color: inherit;
}

input,
textarea,
select {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--border-radius);
  background-color: var(--color-background);
}

input:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px var(--color-accent);
}

button {
  padding: var(--spacing-sm) var(--spacing-lg);
  background-color: var(--color-background);
  color: var(--color-text);
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: background-color var(--transition-speed) var(--transition-timing);
}

button:hover {
  background-color: var(--color-accent);
}

/* ==================== Layout ==================== */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.section {
  padding: var(--spacing-2xl) 0;
}

/* ==================== Header ==================== */
.header {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  color: var(--color-text);
  padding: var(--spacing-lg) 0;
  position: static;
  top: 0;
  z-index: 100;
  box-shadow: 0 4px 20px rgba(157, 78, 221, 0.25);
  display: grid;
  grid-template-columns: auto 1fr;
}

header h1 {
  width: 100%;
  margin: 0;
  box-sizing: border-box;
  font-size: var(--font-size-5xl);
  line-height: var(--line-height-heading);
  font-weight: var(--font-weight-bold);
  background: linear-gradient(135deg, var(--color-text) 0%, var(--color-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.logo__link {
  width: clamp(12vw, 15vw, 20vw);
  height: auto;
  border-radius: var(--border-radius-md);
  transition: all var(--transition-speed) var(--transition-timing);
  padding: var(--spacing-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 15px var(--color-accent);
}

.logo__link img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.logo__link:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 25px var(--color-accent);
}

.header__title {
  font-size: var(--font-size-xl);
  margin-bottom: 0;
  margin-left: clamp(0.5rem, 3vw, 3rem);
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
}

.header__title p {
  margin: 0;
  font-size: var(--font-size-2xl);
  color: var(--color-text);
}

.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* ==================== Navigation ==================== */
.nav__list {
  display: flex;
  justify-content: center;
  align-items: center;
  min-width: 100vw;
  flex-direction: row;
  margin: 0;
  gap: var(--spacing-xl);
  padding: var(--spacing-2xl) var(--spacing-lg);
  flex-wrap: wrap;
  border-bottom: 2px solid var(--color-accent);
}

.nav__link {
  list-style: none;
  display: flex;
  gap: var(--spacing-lg);
  margin: 0;
  padding: 0;
}

.nav__link a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: clamp(0.75rem, 2vw, 1.5rem) clamp(1.5rem, 3vw, 3rem);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  color: var(--color-text);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  border: none;
  border-radius: var(--border-radius-md);
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-speed) var(--transition-timing);
  box-shadow: 0 4px 15px var(--color-accent);
  min-width: clamp(140px, 30vw, 200px);
  text-align: center;
}

.nav__link a:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 25px var(--color-accent);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  text-decoration: none;
}

.nav__link a:active {
  transform: translateY(-1px);
  box-shadow: 0 3px 12px var(--color-accent);
}

/* ==================== Main & Footer ==================== */
form{
  position: relative;
}

.main {
  min-height: calc(100vh - 200px);
}

.main-content {
  padding: var(--spacing-2xl) 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-2xl);
}

.main-content h2 {
  text-align: center;
  width: 100%;
  margin-bottom: var(--spacing-lg);
}

.wrapper{
  width: 700px;
  max-width: 100%;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer {
  background-color: var(--color-background);
  color: var(--color-secondary);
  text-align: center;
  padding: var(--spacing-2xl) 0;
  margin-top: var(--spacing-3xl);
}

#todo-input{
  box-sizing: border-box;
  padding: 12px 20px;
  width: 100%;
  background: none;
  border: 2px solid var(--color-secondary);
  border-radius: var(--border-radius-full);
  font: inherit;
  color: var(--color-text);
  caret-color: var(--color-accent);
}

#todo-input:focus{
  outline: none;
  border-color: var(--color-accent);
}

#add-btn{
  position: absolute;
  right: 0;
  top: 0;
  background-color: var(--color-accent);
  height: 100%;
  padding: 0 30px;
  border: none;
  border-radius: var(--border-radius-full);
  font: inherit;
  color: var(--color-text);
  cursor: pointer;
}

.todo{
  margin-bottom: 10px;
  padding: 0 16px;
  background-color: transparent;
  border: 2px solid var(--color-secondary);
  border-radius: var(--border-radius-lg);
  display: flex;
  align-items: center;
}

.todo .todo-text{
  padding: 15px;
  padding-right: 0;
  flex-grow: 1;
}

.todo .todo-text:hover{
    color: var(--color-text-light);
}

.delete-btn{
  padding: 1px;
  background: transparent;
  border: none;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  fill: var(--color-text-light);
}

.delete-btn:hover {
  background-color: transparent;
}

.delete-btn:hover svg{
  fill: var(--color-delete);
}

.custom-checkbox{
  border: 2px solid var(--color-accent);
  border-radius: var(--border-radius-full);
  min-height: 20px;
  min-width: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-shrink: 0;
  cursor: pointer;
}

input[type="checkbox"]:checked ~ .custom-checkbox{
    background-color: var(--color-accent);
}
input[type="checkbox"]:checked ~ .custom-checkbox svg{
    fill: var(--color-text-light);
}
input[type="checkbox"]:checked ~ .todo-text{
    text-decoration: line-through;
    color: var(--color-text-light);
}
input[type="checkbox"]{
    display: none;
}

/* ==================== Responsive Design ==================== */
/* Nur noch für Layout-Änderungen, Größen werden per clamp() flüssig skaliert */

@media (max-width: 992px) {
  .header {
    grid-template-columns: auto 1fr;
  }
}

@media (max-width: 768px) {
  .header {
    grid-template-columns: auto 1fr;
  }

  .header .container {
    flex-direction: column;
    gap: var(--spacing-md);
  }

  .nav__list {
    justify-content: center;
  }
}

@media (max-width: 576px) {
  .header {
    grid-template-columns: auto 1fr;
  }

  .nav__list {
    flex-wrap: wrap;
    gap: var(--spacing-md);
  }

  .nav__link {
    width: 100%;
    justify-content: center;
    flex-wrap: wrap;
  }

  .nav__link a {
    width: clamp(90%, auto, 100%);
  }
}

@media (max-width: 400px) {
  .header {
    grid-template-columns: auto 1fr;
  }

  .nav__list {
    flex-direction: column;
    gap: var(--spacing-sm);
  }

  .nav__link {
    width: 100%;
    flex-direction: column;
  }

  .nav__link a {
    width: 100%;
  }
}

/* ==================== Utility Classes ==================== */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }
.hidden { display: none !important; }
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
}