:root {
  --font-serif: 'Inria Serif', serif;
  --font-sans: 'Inria Sans', sans-serif;

  --bg-color: #FDFBF6;      /* Light Eggshell */
  --text-color: #1E364E;    /* Sleepy Teal */
  --accent-purple: #A582C4; /* Morning Purple */
  --accent-green: #639D7D;  /* Optimistic Green */
  --accent-red: #AB5050;    /* Frozen Red */
  --accent-bronze: #A5824C; /* Sudden Bronze */
  --accent-blue: #5A82C4;   /* Liquid Blue */

  --main-padding-top: 80px;
}

[data-theme="dark"] {
  --bg-color: #1E364E;
  --text-color: #FDFBF6;
}

html {
  scroll-padding-top: 20px;
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: var(--font-sans);
  margin: 0;

  padding-top: 120px;

  display: grid;
  grid-template-rows: 1fr auto;
  min-height: 100vh;
  box-sizing: border-box;

  width: 100%;
  overflow-x: hidden;
}

main {
  grid-row: 1 / 2;
}

.main-footer {
  grid-row: 2 / 3;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
}

a {
  color: var(--accent-green);
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  color: var(--accent-purple);
}

.header-wrapper {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background-color: var(--bg-color);
  z-index: 1000;
  transition: transform 0.4s ease-in-out;
}

.header-wrapper.hidden {
  transform: translateY(-100%);
}

.main-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 50px;
  max-width: 1400px;
  margin: 0 auto;
}

.logo-container {
  display: flex;
  align-items: center;
}

.site-title {
  font-family: var(--font-serif);
  font-size: clamp(1.3rem, 4vw, 1.8rem);
  margin: 0;
  color: var(--text-color);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 30px;
}

.nav-link {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 1rem;
  color: var(--text-color);
  text-decoration: none;
  padding: 5px 0;
  position: relative;
  transition: color 0.3s ease;
}

.nav-link:hover {
  color: var(--accent-purple);
}

.nav-link.active {
  color: var(--accent-green);
}

.header-divider-container {
  max-width: 100vw;
  margin: 0 auto;
  transition: opacity 0.3s ease;
}
.header-divider {
  border-top: 1px solid var(--text-color);
  opacity: 0.5;
}
.header-divider-double {
  border-top: 1px solid var(--text-color);
  margin-top: 2px;
  opacity: 0.5;
}

.dynamic-date {
    position: fixed;
    top: 30px;
    left: 0;
    width: 100%;
    max-width: 1400px;
    padding: 0 50px;
    box-sizing: border-box;
    text-align: right;
    font-family: var(--font-serif);
    color: var(--text-color);
    z-index: 999;
    transition: transform 0.4s ease-in-out, opacity 0.3s ease;
    pointer-events: none;
    transform: translateY(0);
}

.header-wrapper:not(.hidden) + .dynamic-date {
  transform: translateY(65px);
}

.main-layout {
    display: grid;
    grid-template-columns: 280px 1fr 280px;
    gap: 40px;

    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
    padding: 0 50px 40px;
    box-sizing: border-box;

    position: relative;
}

.full-height-line {
    position: absolute;
    left: calc(280px + 20px);

    top: calc(-1 * var(--main-padding-top));
    width: 1px;
    height: calc(100% + var(--main-padding-top));

    background-color: var(--text-color);
    opacity: 0.5;
    z-index: -1;
}

.lab-book-page .sidebar-left {
    padding-right: 30px;
    opacity: 0.8;

    position: sticky;
    top: var(--main-padding-top);
    align-self: start;
    height: calc(100vh - var(--main-padding-top) - 40px);
    overflow-y: auto;
}

.sidebar-right {
    /* Empty right sidebar for spacing */
}

.page-title { font-family: var(--font-serif); font-size: 3.5rem; font-weight: bold; margin-bottom: 2rem; }
.page-subtitle { font-size: 1.2rem; line-height: 1.6; }

.animated-logo {
    width: 50px;
    height: 50px;
    margin-right: 20px;
}

.theme-switcher {
    position: relative;
    z-index: 1001;
}

#theme-toggle-button {
    background: none;
    border: none;
    padding: 0;
    margin: 0;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

#theme-toggle-text {
    display: inline-block;
    min-width: 55px;
    text-align: left;
}

.sidebar-title {
    font-family: var(--font-serif);
    font-size: 1.2rem;
    font-weight: 700;
    margin-top: 10px;
    margin-bottom: 10px;
}

.sidebar-title a {
    display: block;
    padding: 8px 15px;
    border-radius: 5px;
    color: var(--text-color);
    transition: background-color 0.2s ease, color 0.2s ease;
}

.sidebar-title a:hover {
    color: var(--accent-purple);
}

.sidebar-title a.active {
    color: var(--accent-green);
    font-weight: 700;
}

.sidebar-nav ul {
    list-style: none;
    padding-left: 15px;
    margin: 0;
}

.sidebar-nav li a {
    display: block;
    padding: 8px 15px;
    padding-left: 30px;
    font-size: 0.95rem;
    border-radius: 5px;
    color: var(--text-color);
    transition: background-color 0.2s ease, color 0.2s ease;
}

.sidebar-nav li a:hover {
    color: var(--accent-purple);
}

.animation-container {
    margin: 30px 0;
    text-align: center;
}

figcaption {
    margin-top: 10px;
    font-style: italic;
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.8;
    text-align: left;
}

.main-content img,
.main-content figure {
    max-width: 100%;
    height: auto;
    box-sizing: border-box;
}

.main-footer {
    padding: 20px 0;
    text-align: center;
    background-color: var(--bg-color);
    font-size: 0.9rem;
    border-top: 1px solid var(--text-color);
    opacity: 1;
}

.main-footer a {
    font-weight: bold;
}

.mobile-sidebar-toggle-container {
    display: none; /* Hidden on desktop */
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1005;
}

#mobile-sidebar-toggle {
    background-color: var(--text-color);
    color: var(--bg-color);
    border: none;
    padding: 12px 25px;
    border-radius: 30px;
    font-family: var(--font-sans);
    font-weight: 700;
    font-size: 1rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    cursor: pointer;
    opacity: 0.8;
}


.mobile-nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    z-index: 1005;
}

.hamburger-icon {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    position: relative;
    transition: background-color 0s 0.2s;
}

.hamburger-icon::before,
.hamburger-icon::after {
    content: '';
    display: block;
    width: 100%;
    height: 100%;
    background-color: var(--text-color);
    position: absolute;
    left: 0;
    transition: transform 0.2s ease-in-out;
}

.hamburger-icon::before { top: -8px; }
.hamburger-icon::after { top: 8px; }

body.mobile-nav-active .hamburger-icon { background-color: transparent; }
body.mobile-nav-active .hamburger-icon::before { transform: translateY(8px) rotate(45deg); }
body.mobile-nav-active .hamburger-icon::after { transform: translateY(-8px) rotate(-45deg); }


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

    .full-height-line {
        display: none;
    }

    .sidebar-left, .sidebar-right {
        display: none;
    }

    .lab-book-layout .sidebar-left {
        display: block;
        position: fixed;
        top: 0;
        left: 0;
        width: 85%;
        height: 100vh;
        background-color: var(--bg-color);
        z-index: 1004;
        transform: translateX(-100%);
        transition: transform 0.3s ease-in-out;
        overflow-y: auto;
        padding: 100px 20px 40px;
        border-right: 1px solid var(--text-color);
    }

    body.sidebar-visible .sidebar-left {
        transform: translateX(0);
    }

    body.lab-book-page .mobile-sidebar-toggle-container {
        display: block;
    }

    body.sidebar-visible .main-layout .main-content {
        display: none;
    }
}

/* For mobile phones */
@media (max-width: 768px) {
    .main-header {
        padding: 15px 20px;
    }

    .main-nav {
        position: fixed;
        top: 0;
        right: 0;
        width: 100%;
        height: 100vh;
        background-color: var(--bg-color);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 40px;
        transform: translateX(100%);
        transition: transform 0.3s ease-in-out;
        z-index: 1001;
    }

    body.mobile-nav-active .main-nav {
        transform: translateX(0);
    }

    .mobile-nav-toggle {
        display: block;
    }

    .site-title {
        font-size: 1rem;
    }

    .dynamic-date {
        display: none;
    }

    body.mobile-nav-active .header-divider-container {
        opacity: 0;
    }

    .main-layout {
        padding: 0 20px 20px;
    }

    .page-title {
        font-size: 1.5rem;
    }
}