:root {
    --bg: #f4f6f8;
    --text: #333;
    --card-bg: #fff;
    --border: #e0e0e0;
    --highlight: #0078D4; /* A slightly brighter blue for better contrast */
    --button-bg-light: linear-gradient(to right, #0078D7, #005bb7);
    --button-text-light: #fff;
    --header-bg-light: linear-gradient(to right, #e0e0e0, #f0f0f0);
    --shadow-color: rgba(0, 0, 0, 0.1);
    --accordion-border: #ddd;
}
body.dark {
    --bg: #1e1e1e;
    --text: #ccc;
    --card-bg: #2e2e2e;
    --border: #444;
    --highlight: #4aa8ff;
    --button-bg-dark: linear-gradient(to right, #0078D7, #005bb7); /* Vibrant blue for dark mode */
    --button-text-dark: #fff;
    --header-bg-dark: #2a2a2a;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --accordion-border: #555;
}

/* Global Styles */
body {
    font-family: 'Segoe UI', Roboto, Helvetica Neue, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    margin: 0;
    padding: 0;
    line-height: 1.6;
    transition: background 0.5s ease, color 0.5s ease;
}
.container {
    max-width: 1300px;
    margin: 0 auto;
    padding: 2rem;
}
a {
    color: var(--highlight);
    text-decoration: none;
    transition: color 0.3s ease;
}
a:hover {
    text-decoration: underline;
    color: var(--highlight);
}

/* Typography */
h1 {
    font-size: 2.5rem;
    font-weight: 600;
    margin: 0;
    color: var(--text);
}
h2 {
    font-size: 1.8rem;
    font-weight: 500;
    color: var(--highlight);
    margin-top: 0;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border);
}
h2 svg {
    width: 28px;
    height: 28px;
    fill: var(--highlight);
}
h3 {
    font-size: 1.3rem;
    font-weight: 500;
    color: var(--text);
    margin: 0;
}
p {
    font-size: 1rem;
    font-weight: 400;
    margin-bottom: 0.5rem;
}
strong {
    font-weight: 600;
}

/* Header */
header {
    background: var(--header-bg-light);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px var(--shadow-color);
    border-bottom-left-radius: 10px;
    border-bottom-right-radius: 10px;
    transition: background 0.5s ease, box-shadow 0.5s ease;
}
body.dark header {
    background: var(--header-bg-dark);
}
.logo-title {
    display: flex;
    align-items: center;
    gap: 1rem;
}
.logo-title img {
    height: 48px;
    width: auto;
}
.header-buttons {
    display: flex;
    gap: 1rem;
}
.action-button {
    background: var(--button-bg-light);
    color: var(--button-text-light);
    border: none;
    padding: 0.75rem 1.25rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: background 0.3s ease, transform 0.1s ease, box-shadow 0.3s ease;
    box-shadow: 0 2px 5px var(--shadow-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.action-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-color);
    text-decoration: none;
}
.action-button:active {
    transform: translateY(0);
    box-shadow: 0 1px 3px var(--shadow-color);
}
body.dark .action-button {
    background: var(--button-bg-dark);
    color: var(--button-text-dark);
}

/* Navigation */
.navbar {
    background-color: var(--card-bg);
    padding: 0.8rem 2rem;
    box-shadow: 0 1px 3px var(--shadow-color);
    margin-bottom: 2rem;
    border-radius: 0 0 8px 8px;
    transition: background 0.5s ease, box-shadow 0.5s ease;
}
.navbar ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
    gap: 2rem;
}
.navbar li a {
    color: var(--text);
    font-weight: 500;
    padding: 0.5rem 0;
    display: block;
    transition: color 0.3s ease;
}
.navbar li a:hover {
    color: var(--highlight);
    text-decoration: none;
}

/* Release Info Layout */
.release-info {
    display: grid;
    gap: 2rem;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}

.release-info-column {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: background 0.5s ease, box-shadow 0.5s ease;
    display: flex;
    flex-direction: column;
}

/* Card Styling */
.card {
    background: var(--card-bg);
    border-radius: 10px;
    border: 1px solid var(--border);
    margin-bottom: 1rem;
    overflow: hidden;
    transition: border 0.5s ease;
}

/* Accordion / Collapsible Styling */
.accordion-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    cursor: pointer;
    transition: background 0.3s ease, border-color 0.5s ease;
}
.accordion-header:hover {
    background-color: rgba(0, 120, 215, 0.05);
}
body.dark .accordion-header:hover {
    background-color: rgba(0, 120, 215, 0.1);
}
.accordion-title {
    margin: 0;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
}
.accordion-button {
    background: none;
    border: 1px solid var(--highlight);
    color: var(--highlight);
    padding: 0.4rem 0.8rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}
.accordion-button:hover {
    background: var(--highlight);
    color: #fff;
    text-decoration: none;
}

/* 折叠动画用 max-height 过渡 */
.accordion-collapse {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease-out;
}
.accordion-collapse.show {
    max-height: 1000px; /* 足够容纳内容的最大高度 */
}
.accordion-body {
    padding: 1rem 1.25rem;
    border-top: 1px solid var(--accordion-border);
}
.accordion-body p {
    margin-bottom: 0.3rem;
    font-size: 0.95rem;
}

/* 额外样式 */
.build-link {
    font-size: 0.95rem;
}
.error-message {
    color: #d9534f;
    font-weight: 500;
    padding: 1rem;
    background-color: #f2dede;
    border: 1px solid #ebccd1;
    border-radius: 8px;
}
body.dark .error-message {
    color: #f8d7da;
    background-color: #721c24;
    border-color: #f5c6cb;
}

/* ISO Download Section */
.iso-download {
    margin-top: auto;
    padding-top: 1.5rem;
    border-top: 1px dashed var(--border);
    text-align: center;
}
.iso-download h3 {
    margin-top: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    color: var(--text);
    border-bottom: none;
    padding-bottom: 0;
    font-size: 1.3rem;
}
.iso-download h3 svg {
    width: 24px;
    height: 24px;
    stroke: var(--highlight);
    fill: none;
}
.iso-download p {
    font-size: 0.9rem;
    color: var(--text);
    margin-bottom: 1rem;
}
.iso-download a {
    display: inline-block;
    background: var(--button-bg-light);
    color: var(--button-text-light);
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    font-weight: 500;
    transition: background 0.3s ease, transform 0.1s ease, box-shadow 0.3s ease;
    box-shadow: 0 2px 5px var(--shadow-color);
}
.iso-download a:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-color);
    text-decoration: none;
}
body.dark .iso-download a {
    background: var(--button-bg-dark);
    color: var(--button-text-dark);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 1rem;
    margin-top: 3rem;
    border-top: 1px solid var(--border);
    font-size: 0.9rem;
    color: var(--text);
    transition: border-color 0.5s ease;
}
footer p {
    margin: 0.5rem 0;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    header, .navbar {
        padding-left: 1rem;
        padding-right: 1rem;
        flex-direction: column;
        gap: 1rem;
    }
    .header-buttons {
        width: 100%;
        justify-content: space-around;
    }
    h1 { font-size: 2rem; }
    h2 { font-size: 1.7rem; }
}