:root {
    /* Light Mode (Default) - Black & White Theme */
    --primary-color: #000000;
    --primary-dark-color: #333333;
    --secondary-color: #555555;
    --accent-color: #000000;
    --background-color: #ffffff;
    --text-color: #000000;
    --light-text-color: #555555;
    --card-background: #ffffff;
    --border-color: #eeeeee;
    --shadow-light: rgba(0, 0, 0, 0.05);
    --shadow-medium: rgba(0, 0, 0, 0.1);
    --header-bg: #ffffff;
    --header-text: #000000;
    --button-bg: #f1f1f1;
    --button-text: #000000;
}

body.dark-mode {
    /* Dark Mode */
    --primary-color: #ffffff;
    --primary-dark-color: #cccccc;
    --secondary-color: #aaaaaa;
    --accent-color: #ffffff;
    --background-color: #121212;
    --text-color: #ffffff;
    --light-text-color: #bbbbbb;
    --card-background: #1e1e1e;
    --border-color: #333333;
    --shadow-light: rgba(255, 255, 255, 0.05);
    --shadow-medium: rgba(255, 255, 255, 0.1);
    --header-bg: #1e1e1e;
    --header-text: #ffffff;
    --button-bg: #333333;
    --button-text: #ffffff;
}

body {
    font-family: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header */
header {
    background-color: var(--header-bg);
    color: var(--header-text);
    padding: 1rem 1.5rem;
    box-shadow: 0 2px 4px var(--shadow-light);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

header h1 {
    margin: 0;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--header-text);
    transition: color 0.3s ease;
}

/* --- Theme Switcher --- */
.theme-switcher {
    position: relative;
}
.theme-switcher label {
    cursor: pointer;
    font-size: 0; /* Hide text */
    width: 50px;
    height: 26px;
    background-color: var(--button-bg);
    border: 1px solid var(--border-color);
    border-radius: 26px;
    display: block;
    position: relative;
    transition: background-color 0.3s ease;
}
.theme-switcher label::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 20px;
    height: 20px;
    background-color: var(--secondary-color);
    border-radius: 50%;
    transition: transform 0.3s ease, background-color 0.3s ease;
}
.theme-switcher input {
    display: none;
}
.theme-switcher input:checked + label {
    background-color: var(--primary-color);
}
.theme-switcher input:checked + label::after {
    background-color: var(--background-color);
    transform: translateX(24px);
}


/* Main Application Container */
#app {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

/* Controls Section (Search & Categories) */
#controls {
    background-color: var(--card-background);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 8px var(--shadow-light);
    margin-bottom: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

#search-input {
    width: 100%;
    padding: 0.8rem 1rem;
    background-color: var(--background-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 1rem;
    box-sizing: border-box;
    transition: border-color 0.3s ease, box-shadow 0.3s ease, background-color 0.3s ease, color 0.3s ease;
}

#search-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--shadow-medium);
    outline: none;
}

#category-tabs { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.category-tab {
    background-color: var(--button-bg);
    color: var(--text-color);
    padding: 0.6rem 1.2rem;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, transform 0.1s ease;
}

.category-tab:hover {
    background-color: var(--primary-dark-color);
    color: var(--background-color);
    border-color: var(--primary-dark-color);
    transform: translateY(-1px);
}

.category-tab.active {
    background-color: var(--primary-color);
    color: var(--background-color);
    border-color: var(--primary-color);
    font-weight: 600;
}
.category-tab.active:hover {
    transform: none;
}

/* Tool List Grid */
#tool-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1.5rem; }

/* Tool Card */
.tool-card {
    background-color: var(--card-background);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 4px 12px var(--shadow-light);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    position: relative;
    overflow: hidden;
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.3s ease, border-color 0.3s ease;
}

.tool-card:hover { transform: translateY(-5px); box-shadow: 0 8px 20px var(--shadow-medium); }
.tool-card h3 { font-size: 1.4rem; color: var(--primary-color); margin: 0.5rem 0 0.75rem; line-height: 1.3; transition: color 0.3s ease; }
.tool-card p { font-size: 0.95rem; color: var(--light-text-color); margin-bottom: 1rem; flex-grow: 1; transition: color 0.3s ease; }

.tool-card .tool-meta { display: flex; justify-content: space-between; align-items: center; margin-top: 1rem; padding-top: 1rem; border-top: 1px dashed var(--border-color); transition: border-color 0.3s ease; }
.tool-card .tool-price { font-weight: 600; color: var(--text-color); background-color: var(--button-bg); padding: 0.3em 0.7em; border-radius: 4px; font-size: 0.85rem; transition: background-color 0.3s ease, color 0.3s ease; }
.tool-card .view-details { color: var(--secondary-color); font-weight: 500; font-size: 0.9rem; transition: color 0.3s ease; }
.tool-card:hover .view-details { color: var(--primary-dark-color); }

/* Badges & Tags */
.tool-badge { position: absolute; top: 0; right: 0; background-color: var(--accent-color); color: var(--background-color); padding: 0.4rem 0.8rem; border-bottom-left-radius: 8px; font-size: 0.8rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.5px; z-index: 10; transition: background-color 0.3s ease, color 0.3s ease; }
.tool-tags { margin-top: 0.75rem; margin-bottom: 0.5rem; display: flex; flex-wrap: wrap; gap: 0.4rem; }
.tool-tags span { background-color: var(--button-bg); color: var(--light-text-color); padding: 0.25rem 0.6rem; border-radius: 15px; font-size: 0.75rem; white-space: nowrap; transition: background-color 0.3s ease, color 0.3s ease; }

/* Detail View */
#detail-view-container { display: none; background-color: var(--card-background); padding: 2rem; border-radius: 8px; border: 1px solid var(--border-color); box-shadow: 0 4px 12px var(--shadow-light); transition: background-color 0.3s ease, border-color 0.3s ease; }
.detail-view #back-button { background: var(--button-bg); border: 1px solid var(--border-color); color: var(--text-color); padding: 0.5rem 1rem; border-radius: 5px; cursor: pointer; font-size: 0.9rem; margin-bottom: 2rem; transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease; }
.detail-view #back-button:hover { background-color: var(--primary-dark-color); color: var(--background-color); }
.detail-view .detail-header { display: flex; justify-content: space-between; align-items: center; border-bottom: 1px solid var(--border-color); padding-bottom: 1rem; margin-bottom: 1.5rem; transition: border-color 0.3s ease; }
.detail-view h1 { font-size: 2.2rem; color: var(--text-color); margin: 0; transition: color 0.3s ease; }
.detail-view .primary-link { background-color: var(--primary-color); color: var(--background-color); padding: 0.7rem 1.5rem; border-radius: 5px; text-decoration: none; font-weight: 600; white-space: nowrap; transition: background-color 0.3s ease, color 0.3s ease; }
.detail-view .primary-link:hover { background-color: var(--primary-dark-color); }
.detail-view .detail-description { font-size: 1.1rem; color: var(--light-text-color); margin-bottom: 2rem; transition: color 0.3s ease; }
.detail-view h3 { font-size: 1.5rem; color: var(--primary-color); margin: 2rem 0 1rem; transition: color 0.3s ease; }
.detail-view .detail-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; }
.detail-view ul { list-style-type: '✓ '; padding-left: 20px; }
.detail-view ul li { margin-bottom: 0.5rem; }

/* Responsive Adjustments */
@media (max-width: 768px) {
    header h1 { font-size: 1.5rem; }
    #controls, #detail-view-container { padding: 1rem; }
    .detail-view .detail-header { flex-direction: column; align-items: flex-start; gap: 1rem; }
    .detail-view h1 { font-size: 1.8rem; }
    .detail-view .detail-columns { grid-template-columns: 1fr; gap: 0; }
}
    @media (max-width: 480px) {
    #app { margin: 1rem auto; padding: 0 0.5rem; }
    #tool-list { grid-template-columns: 1fr; }
    .tool-card .tool-meta { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
}

/* --- Contact Form Section --- */
#contact-form-section {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 12px var(--shadow-light);
    margin-top: 3rem;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

#contact-form-section h2 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-top: 0;
    margin-bottom: 2rem;
    text-align: center;
    transition: color 0.3s ease;
}

#partnership-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-color);
    transition: color 0.3s ease;
}

#partnership-form input[type="text"],
#partnership-form input[type="email"],
#partnership-form textarea {
    padding: 0.8rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 1rem;
    background-color: var(--background-color);
    color: var(--text-color);
    transition: border-color 0.3s ease, box-shadow 0.3s ease, background-color 0.3s ease, color 0.3s ease;
}

#partnership-form input[type="text"]:focus,
#partnership-form input[type="email"]:focus,
#partnership-form textarea:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--shadow-medium);
    outline: none;
}

#partnership-form textarea {
    resize: vertical;
}

#partnership-form button[type="submit"] {
    background-color: var(--primary-color);
    color: var(--background-color);
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 5px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease, color 0.3s ease;
}

#partnership-form button[type="submit"]:hover {
    background-color: var(--primary-dark-color);
}

/* --- AdSense Container --- */
.ad-container {
    margin-bottom: 2rem;
    text-align: center;
    background-color: var(--button-bg);
    border-radius: 8px;
    padding: 1rem 0;
    transition: background-color 0.3s ease;
}

.ad-container-detail {
    margin: 2rem 0;
}