:root {
    --bg-color: #0d1117;
    --card-bg: #161b22;
    --border-color: #30363d;
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --accent-color: #58a6ff;
    --highlight-color: #1f6feb;
    --danger-color: #da3633;
    --success-color: #238636;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
    margin: 0;
    padding: 0;
    line-height: 1.5;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1.5rem;
    /* Increased slightly for logo */
    margin-bottom: 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    margin: 0;
    line-height: 0;
}

.logo {
    height: 40px;
    width: auto;
    display: block;
    transition: transform 0.3s ease, filter 0.3s ease;
}

.logo:hover {
    transform: scale(1.02);
    filter: brightness(1.1);
}

h1,
h2,
h3 {
    margin-top: 0;
}

a {
    color: var(--accent-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.button {
    background-color: var(--success-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    text-decoration: none;
    display: inline-block;
}

.button:hover {
    background-color: #2ea043;
    text-decoration: none;
}

.button.secondary {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}

.button.secondary:hover {
    background-color: var(--border-color);
}

.button.danger {
    background-color: var(--danger-color);
}

.card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 1rem;
    margin-bottom: 1rem;
}

input[type="text"],
input[type="number"],
input[type="password"],
textarea,
select {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.75rem;
    border-radius: 6px;
    width: 100%;
    box-sizing: border-box;
    margin-bottom: 1rem;
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

input[type="text"]:focus,
input[type="number"]:focus,
input[type="password"]:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.3);
}

/* Specific adjustments for login cards */
.card-header {
    background-color: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem;
    border-radius: 6px 6px 0 0;
}

.card-body {
    padding: 1.5rem;
}

/* Improve button consistency */
.btn-primary {
    background-color: var(--success-color);
    color: white;
    padding: 0.75rem 1rem;
    border-radius: 6px;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    width: 100%;
    font-weight: 600;
    transition: background-color 0.2s;
}

.btn-primary:hover {
    background-color: #2ea043;
}

label {
    display: block;
    margin-bottom: 0.3rem;
    color: var(--text-secondary);
}

table {
    width: 100%;
    border-collapse: collapse;
}

th,
td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    color: var(--text-secondary);
}

/* Flash Messages */
.flash {
    padding: 0.75rem;
    margin-bottom: 1rem;
    border-radius: 6px;
}

.flash.success {
    background-color: rgba(35, 134, 54, 0.2);
    border: 1px solid var(--success-color);
}

.flash.error {
    background-color: rgba(218, 54, 51, 0.2);
    border: 1px solid var(--danger-color);
}

.formula-display {
    font-size: 1.5rem;
    padding: 1rem;
    text-align: center;
    background: #000;
    border-radius: 6px;
    margin-bottom: 1rem;
}

.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: var(--highlight-color);
    color: var(--text-primary);
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Upload Zone Styles */
.upload-zone {
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    background-color: rgba(255, 255, 255, 0.05);
    /* very subtle fill */
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    margin-bottom: 1rem;
}

.upload-zone:hover,
.upload-zone.dragover {
    border-color: var(--highlight-color);
    background-color: rgba(64, 224, 208, 0.1);
}

.upload-zone p {
    margin: 0;
    color: var(--text-secondary);
    pointer-events: none;
    /* Let clicks pass through */
}

.upload-zone input[type="file"] {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: pointer;
}

.image-preview-container {
    margin-top: 1rem;
    position: relative;
    display: inline-block;
}

.image-preview {
    max-width: 200px;
    max-height: 200px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    display: block;
}

.delete-image-btn {
    position: absolute;
    top: -10px;
    right: -10px;
    background: #ff4444;
    color: white;
    border: none;
    border-radius: 50%;
    width: 24px;
    height: 24px;
    line-height: 24px;
    text-align: center;
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    font-weight: bold;
}

.delete-image-btn:hover {
    background: #cc0000;
}

/* Calculator View Image */
.calculator-image-container {
    text-align: center;
    margin-bottom: 2rem;
}

.calculator-image {
    max-width: 100%;
    max-height: 400px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    object-fit: contain;
    background-color: rgba(0, 0, 0, 0.2);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
}

footer {
    margin-top: 4rem;
    padding: 2rem 0;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-primary);
    font-size: 0.875rem;
    background-color: var(--bg-color);
}

footer a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s;
}

footer a:hover {
    color: var(--accent-color);
    text-decoration: none;
}