:root {
    --swu-maroon: #961113;
    --swu-maroon-dark: #7a0c0e;
    --swu-gray: #ADADAD;
    --swu-light-gray: #F2F2F2;
    --text-dark: #1a1a1a;
    --text-light: #ffffff;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --radius: 12px;
    --font-mono: 'IBM Plex Mono', monospace;
    --font-sans: 'Inter', sans-serif;
}

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-dark);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.app-header {
    background-color: var(--swu-maroon);
    color: var(--text-light);
    padding: 2rem 1rem;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.app-header h1 {
    margin: 0;
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.subtitle {
    margin: 0.5rem 0 0;
    opacity: 0.9;
    font-size: 0.9rem;
    font-family: var(--font-mono);
}

/* Container */
.container {
    max-width: 800px;
    margin: -30px auto 40px; /* Overlap header slightly */
    padding: 0 1rem;
    flex: 1;
    z-index: 10;
    position: relative;
    width: 100%;
    box-sizing: border-box;
}

/* Mode Selector */
.mode-selector {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.mode-btn {
    background-color: var(--card-bg);
    border: 2px solid transparent;
    padding: 0.8rem 1.5rem;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    color: var(--text-dark);
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    transition: all 0.3s ease;
}

.mode-btn.active {
    background-color: var(--swu-maroon);
    color: var(--text-light);
    box-shadow: 0 4px 15px rgba(150, 17, 19, 0.3);
}

.mode-btn:hover:not(.active) {
    background-color: #eee;
}

/* Calculator Card */
.calculator-card {
    background-color: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
    animation: fadeIn 0.4s ease-out;
}

.calculator-card.hidden {
    display: none;
}

.card-header {
    text-align: center;
    margin-bottom: 2rem;
}

.card-header h2 {
    margin: 0;
    color: var(--swu-maroon);
    font-size: 1.5rem;
}

.card-header p {
    color: #666;
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

/* Detailed Mode Styles */
.periods-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
}

.period-group {
    background-color: #fff;
    border: 1px solid #eee;
    padding: 1rem;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
}

.period-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    border-bottom: 2px solid var(--swu-maroon);
    padding-bottom: 0.5rem;
}

.period-header h3 {
    margin: 0;
    font-size: 1.1rem;
    color: #333;
}

.period-avg {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    background: var(--swu-light-gray);
    padding: 2px 6px;
    border-radius: 4px;
    font-weight: 600;
}

.grades-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1rem;
    max-height: 300px;
    overflow-y: auto;
}

.grade-input-wrapper {
    display: flex;
    gap: 0.5rem;
}

.grade-input {
    width: 100%;
    padding: 0.6rem;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-family: var(--font-mono);
    font-size: 1rem;
    text-align: center;
    transition: border-color 0.2s;
}

.grade-input:focus {
    outline: none;
    border-color: var(--swu-maroon);
}

.remove-btn {
    background: #ffeded;
    color: #ff4d4d;
    border: none;
    border-radius: 6px;
    width: 36px;
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
}

.remove-btn:hover {
    background: #ffd6d6;
}

.add-grade-btn {
    margin-top: auto;
    background: transparent;
    border: 1px dashed #aaa;
    color: #666;
    padding: 0.6rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.add-grade-btn:hover {
    border-color: var(--swu-maroon);
    color: var(--swu-maroon);
    background: #fff5f5;
}

/* Quick Mode Styles */
.quick-inputs {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: 400px;
    margin: 0 auto;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #444;
}

.input-group input {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-family: var(--font-mono);
    font-size: 1.1rem;
    text-align: center;
    box-sizing: border-box; /* Fix width overflow */
}

/* Results Section */
.results-section {
    text-align: center;
    margin-top: 1rem;
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    max-width: 800px; /* Match container */
    margin: 0 auto;
}

.calculate-btn {
    background-color: var(--swu-maroon);
    color: white;
    border: none;
    padding: 1rem 3rem;
    font-size: 1.1rem;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    margin-bottom: 2rem;
    box-shadow: 0 4px 15px rgba(150, 17, 19, 0.4);
    transition: transform 0.2s, box-shadow 0.2s;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(150, 17, 19, 0.5);
    background-color: var(--swu-maroon-dark);
}

.calculate-btn:active {
    transform: translateY(1px);
}

.results-display {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.result-box {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.result-label {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.result-value {
    font-family: var(--font-mono);
    font-size: 2.5rem;
    font-weight: 700;
    color: #333;
}

.result-box.highlight .result-value {
    color: var(--swu-maroon);
    font-size: 3.5rem;
}

.result-divider {
    width: 1px;
    height: 60px;
    background: #ddd;
}

.gpa-message {
    font-weight: 500;
    color: #555;
    min-height: 1.5rem;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    color: #888;
    font-size: 0.85rem;
    margin-top: auto;
}

/* Responsive */
@media (max-width: 600px) {
    .app-header h1 {
        font-size: 1.5rem;
    }
    
    .results-display {
        flex-direction: column;
        gap: 1.5rem;
    }
    
    .result-divider {
        width: 60%;
        height: 1px;
    }

    .container {
        padding: 0 0.5rem;
    }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Remove Arrows from Number Input */
input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
input[type=number] {
  -moz-appearance: textfield;
}
/* Semester Block */
.semester-block {
    background-color: #fcfcfc;
    border: 1px solid #eee;
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    position: relative;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}

.semester-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px dashed #eee;
}

.semester-header h3 {
    margin: 0;
    color: var(--swu-maroon);
    font-size: 1.2rem;
}

.remove-sem-btn {
    background: transparent;
    border: none;
    color: #ff4d4d;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0 0.5rem;
    line-height: 1;
    transition: color 0.2s;
}

.remove-sem-btn:hover {
    color: #cc0000;
}

.add-semester-btn {
    display: block;
    width: 100%;
    background-color: transparent;
    border: 2px dashed var(--swu-gray);
    color: #666;
    padding: 1rem;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 1rem;
}

.add-semester-btn:hover {
    border-color: var(--swu-maroon);
    color: var(--swu-maroon);
    background-color: #fffafa;
}

/* Results Updates */
#semesters-results {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    justify-content: center;
}

.sem-result-item {
    text-align: center;
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 8px;
    min-width: 120px;
}

.sem-result-item h4 {
    margin: 0 0 0.5rem;
    font-size: 0.85rem;
    color: #666;
    font-weight: 600;
}

.sem-result-item .sem-gpa {
    display: block;
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 700;
    color: #333;
}