:root {
  /* Colors */
  --color-light-purple: #9498E7;
  --color-faint-purple: #8D7DC7;
  --color-dark-purple: #524A72;
  --color-black-purple: #44344F;
  --color-white: #FFFFFF;
  --color-bg-primary: #f0f2f5;
  --color-bg-secondary: var(--color-white);

  /* Fonts */
  --font-primary: 'GmarketMedium', sans-serif;

  /* Font Sizes */
  --fs-base: 1rem;      /* 16px */
  --fs-lg: 1.25rem;     /* 20px */
  --fs-xl: 1.5rem;      /* 24px */
  --fs-2xl: 2.5rem;     /* 40px */
  --fs-display: 3.5rem; /* 56px */

  /* Spacing */
  --space-sm: 10px;
  --space-md: 20px;
  --space-lg: 40px;
  --space-xl: 60px;
  --space-xxl: 100px;

  /* Others */
  --header-height: 95px;
  --border-radius-sm: 15px;
  --border-radius-md: 20px;
  --shadow-sm: 0 4px 8px rgba(0,0,0,0.1);
  --shadow-md: 0 8px 16px rgba(0,0,0,0.2);
  --transition-fast: 0.3s ease;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-primary);
  padding-top: var(--header-height);
}

body::-webkit-scrollbar {
  display: none;
}

h2 {
  font-weight: bold;
  font-size: var(--fs-2xl);
  color: var(--color-dark-purple);
}

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

ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

/* --- Header --- */
#header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: var(--space-lg) var(--space-xl);
  background-color: var(--color-bg-secondary);
}

.nav-list {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: var(--space-lg);
}

.nav-list a {
    display: inline-block;
    padding: 10px 25px;
    border-radius: 999px;
    font-size: var(--fs-lg);
    font-weight: bold;
    text-decoration: none;
    
    transition: all var(--transition-fast);
    
    border: 2px solid transparent; 
}

.nav-list a:hover {
    color: var(--color-white);
    background-color: var(--color-faint-purple);
}

.bar-bg {
  position: absolute;
  bottom: 0; left: 0;
  width: 100%;
  height: 5px;
  background-color: var(--color-faint-purple);
}

.bar-ing {
  position: absolute;
  bottom: 0; left: 0;
  height: 5px;
  background-color: var(--color-dark-purple);
  width: 0; 
}

/* --- Home --- */
#home {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: calc(100vh - var(--header-height));
  padding: 0 50px var(--space-xxl) 200px;
  background-color: var(--color-light-purple);
  scroll-margin-top: var(--header-height);
}

.home-content {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  max-width: 1200px;
  width: 100%;
}

.profile-img {
  width: 250px; height: 250px;
  border-radius: 50%;
  object-fit: cover;
}

.txt-title {
  font-size: var(--fs-display);
  color: var(--color-dark-purple);
  font-weight: bold;
  line-height: 1.3;
}

.cursor {
  display: inline-block;
  width: 3px;
  height: 1.1em;
  background-color: var(--color-dark-purple);
  margin-left: 5px;
  animation: blink-caret 0.75s step-end infinite;
}

@keyframes blink-caret {
  50% { background-color: transparent; }
}

/* --- About --- */
#about {
  padding: var(--space-xxl) 20px;
  background-color: var(--color-bg-secondary);
  scroll-margin-top: var(--header-height);
  text-align: center;
}

.about-info {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-md);
  max-width: 800px;
  margin: var(--space-lg) auto var(--space-xl) auto;
  gap: var(--space-lg);
}

.about-info div {
  display: flex;
  align-items: baseline;
}

.about-info dt {
  width: 120px;
  font-size: var(--fs-xl);
  font-weight: bold;
  text-align: left;
  color: var(--color-black-purple);
  margin-right: var(--space-md);
}

.about-info dd {
  font-size: var(--fs-xl);
  text-align: left;
  color: var(--color-faint-purple);
  margin-left: 0;
}

.hobby-container {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-lg);
}

.flip-card {
  background-color: transparent;
  width: 400px;
  height: 300px;
  perspective: 1000px;
}

.flip-card-inner {
  position: relative;
  width: 100%; height: 100%;
  text-align: center;
  transition: transform 0.6s;
  transform-style: preserve-3d;
}

.flip-card:hover .flip-card-inner {
  transform: rotateY(180deg);
}

.flip-card-front, .flip-card-back {
  position: absolute;
  width: 100%; height: 100%;
  backface-visibility: hidden;
  border-radius: var(--border-radius-md);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: var(--space-md);
}

.flip-card-front {
  background-color: var(--color-bg-secondary);
  color: var(--color-black-purple);
}

.flip-card-front img {
    width: 100%;
    margin-bottom: var(--space-md);
}

.card-title {
    font-size: var(--fs-xl);
    font-weight: bold;
}

.flip-card-back {
  background-color: var(--color-light-purple);
  color: var(--color-white);
  transform: rotateY(180deg);
}


.flip-card-back h3 {
    font-weight: bold;
    font-size: var(--fs-xl);
    margin-bottom: var(--space-md);
}

.flip-card-back h4 {
    font-weight: bold;
    margin: 7px;
}

.flip-card-back p {
    font-size: var(--fs-base);
    line-height: 1.6;
}

/* --- Projects --- */
#projects {
  padding: var(--space-xxl) 20px;
  background-color: var(--color-bg-primary);
  scroll-margin-top: var(--header-height);
  text-align: center;
}

.projects-grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
  margin-top: var(--space-lg);
}

.project-card {
  background-color: var(--color-bg-secondary);
  width: 700px;
  border-radius: var(--border-radius-sm);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

.project-card:hover {
  transform: translateY(-20px);
  box-shadow: var(--shadow-md);
}

/* --- Project Content --- */
.project-content {
    padding: var(--space-md);
    text-align: left;
}

.project-content h4 {
    font-weight: bold;
    font-size: var(--fs-xl);
    margin-bottom: var(--space-sm);
}

.project-details dt {
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--color-dark-purple);
    margin-top: var(--space-md);
}

.project-details dd {
    font-size: var(--fs-base);
    line-height: 1.6;
    margin-left: 0;
    margin-top: 10px;
}

.tech-stack {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag {
    background-color: #e0e3fd;
    color: var(--color-dark-purple);
    padding: 5px 12px;
    border-radius: 15px;
    font-size: 0.85rem;
}

/* --- Footer --- */
footer {
  background-color: var(--color-black-purple);
  color: var(--color-white);
  text-align: center;
  padding: var(--space-lg);
}

footer h2 {
  font-weight: bold;
  font-size: 2.0rem;
  color: var(--color-white);
  margin-bottom: var(--space-lg);
}

.link-list {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-lg);
}

.link-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-white);
}

.link-item img {
    width: 40px;
    height: 40px;
}

.link-item span {
    font-size: 18px;
    font-weight: bold;
    transition: color var(--transition-fast); 
}

.link-item:hover span {
  color: var(--color-faint-purple);
}

.contact-list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.contact-list div {
  display: flex;
  align-items: center;
}

.contact-list div {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
}

.contact-list dt {
    font-weight: bold;
    margin-right: var(--space-sm);
    color: var(--color-faint-purple);
}

.contact-list dd {
    margin: 0;
    color: var(--color-white);
}

.copyright {
    font-size: var(--fs-base);
}