:root {
    /* Heju Palette */
    --color-bg: #fdfbf7;
    --color-surface: #ffffff;
    --color-primary: #1B3C35;
    --color-primary-hover: #265248;
    --color-text-main: #1D1D1D;
    --color-text-muted: #6B7280;
    --color-border: #E5E7EB;
    --color-success: #2e7d32;
    --color-danger: #d32f2f;
    --color-shadow: rgba(0, 0, 0, 0.05);

    /* Spacing & Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --shadow-sm: 0 1px 2px var(--color-shadow);
    --shadow-md: 0 4px 12px var(--color-shadow);

    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
}

/* Dark Mode (Manual Toggling) */
body.dark-mode {
    --color-bg: #121212;
    --color-surface: #1e1e1e;
    --color-primary: #A7D7C5;
    /* Pastel Green */
    --color-primary-hover: #86C1AD;
    --color-text-main: #E0E0E0;
    --color-text-muted: #A0A0A0;
    --color-border: #333333;
    --color-success: #66BB6A;
    --color-danger: #EF5350;
    --color-shadow: rgba(0, 0, 0, 0.5);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font-main);
    background-color: var(--color-bg);
    color: var(--color-text-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    padding: 2rem;
}

h1,
h2,
h3,
h4,
h5 {
    font-weight: 500;
    margin-top: 0;
    color: var(--color-primary);
    letter-spacing: -0.02em;
}

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

/* Cards */
.cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.card {
    background: var(--color-surface);
    border-radius: var(--radius-md);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
    transition: transform 0.2s;
}

.card:hover {
    transform: translateY(-2px);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 1rem;
}

.card-header h2 {
    margin: 0;
    font-size: 1.25rem;
    color: var(--color-text-main);
}

.device-type {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    font-weight: 600;
    background: var(--color-bg);
    padding: 4px 8px;
    border-radius: var(--radius-sm);
}

.status-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.03);
}

.label {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

.value {
    font-weight: 600;
}

.value.loading {
    color: var(--color-text-muted);
    font-style: italic;
}

/* Buttons */
.btn-unlock {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: 0.85rem 1.5rem;
    border-radius: var(--radius-sm);
    border: none;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    background-color: var(--color-primary);
    color: white;
    margin-top: 1.5rem;
}

.btn-unlock:hover:not(:disabled) {
    background-color: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(27, 60, 53, 0.2);
}

.btn-unlock:disabled {
    background-color: var(--color-border);
    cursor: not-allowed;
    color: var(--color-text-muted);
}

/* Feedback */
.message-area {
    margin-top: 1rem;
    text-align: center;
    font-size: 0.9rem;
    min-height: 1.5em;
}

.success,
.flash-success {
    color: var(--color-success);
}

.error,
.flash-error {
    color: var(--color-danger);
}

.warning-card {
    text-align: center;
    border-color: var(--color-danger);
    background-color: #fff8f8;
}

.warning-icon {
    color: var(--color-danger);
    margin-bottom: 1rem;
}

.warning-title {
    color: var(--color-danger);
}