:root {
    --bg-color: #0a0a0a;
    --card-bg: #141414;
    --text-color: #ffffff;
    --text-muted: #737373;
    --border-color: #262626;
    --accent-color: #ffffff;
    --accent-text: #0a0a0a;
    --hover-color: #1f1f1f;
    --radius: 0px; /* Sharp corners */
}

body.light-mode {
    --bg-color: #f5f5f5;
    --card-bg: #ffffff;
    --text-color: #1a1a1a;
    --text-muted: #666666;
    --border-color: #e5e5e5;
    --accent-color: #1a1a1a;
    --accent-text: #ffffff;
    --hover-color: #f0f0f0;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 40px 20px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1000px;
    width: 100%;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 50px;
    box-shadow: none; /* Flat design */
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.top-bar {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 20px;
}

.theme-toggle-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 8px 16px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    text-transform: uppercase;
    font-family: inherit;
}

.theme-toggle-btn:hover {
    background-color: var(--hover-color);
}

header {
    text-align: left;
    margin-bottom: 50px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 20px;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 800; /* Extra bold for Inter */
    color: var(--text-color);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: -1px;
}

header p {
    font-size: 1rem;
    color: var(--text-muted);
}

/* Tabs */
.tabs {
    display: flex;
    justify-content: flex-start;
    gap: 0;
    margin-bottom: 40px;
    border-bottom: 1px solid var(--border-color);
}

.tab-btn {
    background: transparent;
    border: 1px solid transparent;
    border-bottom: none;
    padding: 12px 24px;
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s ease;
    text-transform: uppercase;
    font-family: inherit;
}

.tab-btn:hover {
    color: var(--text-color);
    background-color: var(--hover-color);
}

.tab-btn.active {
    color: var(--accent-text);
    background-color: var(--accent-color);
    border-color: var(--border-color);
}

.tab-content {
    display: none;
    width: 100%;
}

.tab-content.active {
    display: block;
}

/* DNS Server Selector */
.dns-server-selector {
    display: flex;
    flex-wrap: wrap;
    gap: 0;
    justify-content: flex-start;
    margin-bottom: 30px;
    border: 1px solid var(--border-color);
}

.dns-option {
    background: transparent;
    border: 1px solid var(--border-color);
    margin: -1px;
    padding: 12px 20px;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s ease;
    flex: 1;
    text-align: center;
    text-transform: uppercase;
    font-family: inherit;
}

.dns-option:hover {
    background-color: var(--hover-color);
    color: var(--text-color);
}

.dns-option.active {
    background-color: var(--accent-color);
    color: var(--accent-text);
    border-color: var(--accent-color);
}

/* Search Box */
.search-box {
    display: flex;
    background: transparent;
    border: 1px solid var(--border-color);
    margin-bottom: 40px;
}

.search-box:focus-within {
    border-color: var(--accent-color);
}

.search-box input {
    flex: 1;
    border: none;
    outline: none;
    font-size: 1rem;
    padding: 15px 20px;
    background: transparent;
    color: var(--text-color);
    font-family: inherit;
}

.search-box input::placeholder {
    color: var(--text-muted);
}

.search-box button {
    background: var(--accent-color);
    color: var(--accent-text);
    border: none;
    padding: 0 30px;
    font-size: 0.9rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s ease;
    text-transform: uppercase;
    font-family: inherit;
}

.search-box button:hover {
    background-color: var(--text-muted);
    color: var(--bg-color);
}

/* Results */
.results-container {
    display: grid;
    grid-template-columns: 1fr;
    gap: 30px;
    margin-top: 20px;
}

.card {
    background: transparent;
    border: 1px solid var(--border-color);
}

.card-header {
    background: var(--hover-color);
    padding: 15px 20px;
    border-bottom: 1px solid var(--border-color);
}

.card-header h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-color);
    text-transform: uppercase;
}

.card-body {
    padding: 20px;
}

.card-body ul {
    list-style: none;
}

.card-body li {
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.9rem;
    color: var(--text-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-body li:last-child {
    border-bottom: none;
}

.provider-badge {
    font-size: 0.75rem;
    padding: 2px 8px;
    border: 1px solid var(--border-color);
    font-weight: 700;
    background: transparent;
    color: var(--text-muted);
    text-transform: uppercase;
}

.provider-badge.google { border-color: var(--text-color); color: var(--text-color); }
.provider-badge.aws { border-color: var(--text-color); color: var(--text-color); }
.provider-badge.cloudflare { border-color: var(--text-color); color: var(--text-color); }
.provider-badge.azure { border-color: var(--text-color); color: var(--text-color); }

/* Upload Box */
.upload-box {
    background: transparent;
    padding: 40px;
    border: 1px solid var(--border-color);
}

.upload-box h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--text-color);
    text-transform: uppercase;
}

.upload-box p {
    color: var(--text-muted);
    margin-bottom: 30px;
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 700;
    color: var(--text-color);
    text-transform: uppercase;
    font-size: 0.9rem;
}

.form-group input[type="text"],
.form-group input[type="file"] {
    width: 100%;
    padding: 14px;
    border: 1px solid var(--border-color);
    font-size: 1rem;
    background: transparent;
    color: var(--text-color);
    outline: none;
    font-family: inherit;
}

.form-group input[type="text"]:focus,
.form-group input[type="file"]:focus {
    border-color: var(--accent-color);
}

#uploadBtn {
    background: var(--accent-color);
    color: var(--accent-text);
    border: none;
    padding: 16px 30px;
    font-size: 0.9rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s ease;
    width: 100%;
    text-transform: uppercase;
    font-family: inherit;
}

#uploadBtn:hover {
    background-color: var(--text-muted);
    color: var(--bg-color);
}

.download-link {
    display: inline-block;
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    text-decoration: none;
    padding: 14px 30px;
    font-weight: 700;
    transition: all 0.2s ease;
    text-align: center;
    width: 100%;
    text-transform: uppercase;
    font-size: 0.9rem;
    font-family: inherit;
}

.download-link:hover {
    background-color: var(--hover-color);
}

.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 12px;
    font-size: 1rem;
    color: var(--text-muted);
    margin: 30px 0;
    text-transform: uppercase;
}

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-top-color: var(--accent-color);
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.error-card {
    background: transparent;
    color: #ef4444;
    padding: 20px;
    border: 1px solid #ef4444;
    text-align: center;
    grid-column: 1 / -1;
    text-transform: uppercase;
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .container {
        padding: 30px 20px;
    }
    header h1 {
        font-size: 2rem;
    }
    .dns-server-selector {
        flex-direction: column;
    }
    .dns-option {
        text-align: left;
        padding: 12px;
    }
}