/* Minimalist Black & White Attendance Tracker */

@import url('https://fonts.googleapis.com/css2?family=Inconsolata:wght@400;500;600&display=swap');

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    background: #ffffff;
    min-height: 100vh;
    padding: 20px 15px;
    color: #000000;
    line-height: 1.5;
}

.container {
    max-width: 760px;
    margin: 0 auto;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 24px;
    padding-bottom: 12px;
}

header h1 {
    font-size: 1.8em;
    margin-bottom: 4px;
    font-weight: 700;
    letter-spacing: -0.3px;
    color: #000000;
}

.subtitle {
    font-size: 0.95em;
    font-weight: 400;
    color: #666666;
    letter-spacing: 0.3px;
    text-transform: uppercase;
    font-family: 'Inconsolata', monospace;
}

/* Cards */
.card {
    background: #ffffff;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    padding: 20px;
    margin-bottom: 16px;
}

.card h2 {
    color: #000000;
    margin-bottom: 16px;
    font-size: 1.1em;
    font-weight: 500;
    letter-spacing: -0.2px;
}

/* Forms */
.form-group {
    margin-bottom: 14px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 400;
    color: #000000;
    font-size: 0.85em;
    letter-spacing: 0.2px;
    font-family: 'Inconsolata', monospace;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid #d0d0d0;
    border-radius: 3px;
    background: #ffffff;
    font-size: 14px;
    transition: all 0.2s;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: #000000;
    box-shadow: 0 0 0 1px #000000;
}

/* Buttons */
.btn {
    padding: 8px 16px;
    border: 1px solid #000000;
    border-radius: 3px;
    background: #000000;
    color: #ffffff;
    font-size: 13px;
    font-weight: 400;
    cursor: pointer;
    transition: all 0.2s;
    margin: 4px;
    letter-spacing: 0.3px;
    text-transform: uppercase;
    font-family: inherit;
}

.btn:hover {
    background: #ffffff;
    color: #000000;
}

.btn-primary {
    background: #000000;
    color: #ffffff;
}

.btn-primary:hover {
    background: #ffffff;
    color: #000000;
}

.btn-secondary {
    background: #ffffff;
    color: #000000;
    border: 1px solid #000000;
}

.btn-secondary:hover {
    background: #000000;
    color: #ffffff;
}

.btn-success {
    background: #000000;
    color: #ffffff;
}

.btn-success:hover {
    background: #ffffff;
    color: #000000;
}

.btn-danger {
    background: #ffffff;
    color: #000000;
    border: 1px solid #000000;
}

.btn-danger:hover {
    background: #000000;
    color: #ffffff;
}

.btn-small {
    padding: 8px 16px;
    font-size: 12px;
}

.btn-large {
    width: 100%;
    padding: 18px;
    font-size: 16px;
}

.btn-icon {
    background: none;
    border: none;
    font-size: 16px;
    cursor: pointer;
    padding: 4px 8px;
    opacity: 0.6;
    transition: opacity 0.2s;
}

.btn-icon:hover {
    opacity: 1;
}

/* Collapsible Sections */
.collapsible-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    margin-bottom: 12px;
}

.collapsible-header h2 {
    margin: 0;
}

.toggle-btn {
    background: none;
    border: 1px solid #d0d0d0;
    border-radius: 50%;
    width: 24px;
    height: 24px;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.toggle-btn:hover {
    background: #000000;
    color: #ffffff;
    border-color: #000000;
}

.collapsible-content {
    overflow: hidden;
    transition: max-height 0.3s ease;
    max-height: 2000px;
}

.collapsible-content.collapsed {
    max-height: 0;
}

/* Calendar Highlighting */
input[type="date"]::-webkit-calendar-picker-indicator {
    cursor: pointer;
}

.session-dates-indicator {
    margin-top: 10px;
    padding: 10px;
    background: #f8f8f8;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
}

.session-dates-indicator small {
    color: #666;
    font-size: 0.85em;
}

.session-dates-list-item {
    display: inline-block;
    padding: 3px 8px;
    margin: 2px;
    background: #000000;
    color: #ffffff;
    border-radius: 3px;
    font-size: 0.8em;
    cursor: pointer;
    transition: background 0.2s;
}

.session-dates-list-item:hover {
    background: #333;
}

/* QR Code Section */
#qr-code {
    display: flex;
    justify-content: center;
    margin: 12px 0;
    padding: 16px;
    background: #ffffff;
}

.qr-info {
    background: #f8f8f8;
    padding: 12px;
    border: 1px solid #e0e0e0;
    margin-bottom: 12px;
}

.qr-info p {
    margin: 5px 0;
    font-size: 0.85em;
    color: #000000;
}

.session-info-header {
    background: #f8f8f8;
    padding: 12px;
    border: 1px solid #e0e0e0;
    margin-bottom: 12px;
}

.session-info-header p {
    margin: 5px 0;
    font-size: 0.85em;
    color: #000000;
}

.qr-actions {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 12px;
}

.qr-instructions {
    text-align: center;
    color: #666666;
    font-size: 0.8em;
    margin-top: 12px;
    font-style: italic;
}

/* Stats - Minimalist */
.stats-minimal {
    margin: 0 0 12px 0;
}

.stat-card-minimal {
    padding: 12px 0;
    display: flex;
    justify-content: space-between;
    align-items: baseline;
}

.stat-label-minimal {
    font-size: 0.8em;
    font-weight: 400;
    color: #000000;
    letter-spacing: 0.3px;
    text-transform: uppercase;
}

.stat-value-minimal {
    font-size: 1.5em;
    font-weight: 300;
    color: #000000;
}

/* Session Selector */
.session-selector {
    margin: 30px 0;
}

.session-selector label {
    display: block;
    margin-bottom: 10px;
    font-weight: 400;
    color: #000000;
    font-size: 0.9em;
    letter-spacing: 0.3px;
}

.session-selector select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid #000000;
    border-radius: 6px;
    background: #ffffff;
    font-size: 16px;
    cursor: pointer;
    font-family: inherit;
}

.session-selector select:focus {
    outline: none;
    box-shadow: inset 0 0 0 1px #000000;
}

/* Session Details */
#session-details {
    margin-top: 0;
    padding-top: 0;
}

/* Student List */
.student-list {
    display: flex;
    flex-direction: column;
    gap: 1px;
    margin-top: 12px;
    border: 1px solid #e0e0e0;
    border-radius: 3px;
    overflow: hidden;
}

.student-entry {
    display: flex;
    align-items: center;
    gap: 12px;
    background: #ffffff;
    padding: 10px 12px;
    border-bottom: 1px solid #e0e0e0;
    transition: background 0.2s;
}

.student-entry:last-child {
    border-bottom: none;
}

.student-entry:hover {
    background: #f8f8f8;
}

.student-name {
    flex: 1;
    font-weight: 500;
    color: #000000;
    font-size: 0.9em;
    font-family: 'Inconsolata', monospace;
}

.student-time {
    color: #666666;
    font-size: 0.75em;
    white-space: nowrap;
}

.late-badge {
    display: inline-block;
    background: #000000;
    color: #ffffff;
    padding: 2px 8px;
    font-size: 0.65em;
    margin-left: 8px;
    font-weight: 500;
    letter-spacing: 0.3px;
}

/* Export Actions */
.export-actions {
    display: flex;
    justify-content: flex-start;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid #e0e0e0;
}

/* Student Check-in Page */
.session-details {
    background: #f8f8f8;
    padding: 20px;
    border: 1px solid #e0e0e0;
    margin-bottom: 20px;
}

.session-details p {
    margin: 10px 0;
    font-size: 1em;
    color: #000000;
}

.success-message {
    text-align: center;
    border: 2px solid #000000;
    padding: 40px;
}

.success-icon {
    font-size: 4em;
    color: #000000;
    margin-bottom: 20px;
}

.success-message h2 {
    color: #000000;
    font-weight: 400;
}

.timestamp {
    color: #666666;
    margin-top: 15px;
    font-size: 0.95em;
}

.late-warning {
    background: #f0f0f0;
    color: #000000;
    padding: 15px;
    margin-top: 20px;
    font-weight: 500;
    border: 1px solid #000000;
}

.error-message {
    text-align: center;
    border: 2px solid #000000;
    padding: 40px;
}

.error-icon {
    font-size: 4em;
    color: #000000;
    margin-bottom: 20px;
}

.error-message h2 {
    color: #000000;
    font-weight: 400;
}

.empty-state {
    text-align: center;
    padding: 24px 16px;
    color: #999999;
    border: 1px solid #e0e0e0;
}

.empty-state p {
    font-size: 0.85em;
    font-style: italic;
}

/* Mobile Responsive */
@media (max-width: 600px) {
    body {
        padding: 20px 15px;
    }

    header {
        margin-bottom: 40px;
    }

    header h1 {
        font-size: 2em;
    }

    .card {
        padding: 25px;
    }

    .stat-value-minimal {
        font-size: 1.8em;
    }

    .export-actions {
        flex-direction: column;
    }

    .export-actions .btn {
        width: 100%;
    }
}