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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    padding: 30px;
    max-width: 500px;
    width: 100%;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 24px;
}

/* タブ */
.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    border-bottom: 2px solid #eee;
}

.tab-button {
    flex: 1;
    padding: 12px;
    border: none;
    background: transparent;
    cursor: pointer;
    font-size: 16px;
    color: #666;
    border-bottom: 3px solid transparent;
    transition: all 0.3s;
}

.tab-button:hover {
    color: #667eea;
}

.tab-button.active {
    color: #667eea;
    border-bottom-color: #667eea;
    font-weight: bold;
}

/* パネル */
.panel {
    display: none;
}

.panel.active {
    display: block;
}

/* 表示エリア */
.display {
    font-size: 64px;
    font-weight: bold;
    text-align: center;
    color: #333;
    margin: 30px 0;
    font-variant-numeric: tabular-nums;
    letter-spacing: 2px;
}

/* タイマー入力 */
.timer-inputs {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.input-group label {
    font-size: 14px;
    color: #666;
    font-weight: bold;
}

.input-group input {
    width: 80px;
    padding: 10px;
    font-size: 24px;
    text-align: center;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-variant-numeric: tabular-nums;
}

.input-group input:focus {
    outline: none;
    border-color: #667eea;
}

/* コントロールボタン */
.controls {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.btn {
    flex: 1;
    min-width: 100px;
    padding: 15px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-start {
    background: #4caf50;
    color: white;
}

.btn-start:hover:not(:disabled) {
    background: #45a049;
}

.btn-stop {
    background: #f44336;
    color: white;
}

.btn-stop:hover:not(:disabled) {
    background: #da190b;
}

.btn-reset {
    background: #2196f3;
    color: white;
}

.btn-reset:hover:not(:disabled) {
    background: #0b7dda;
}

.btn-lap {
    background: #ff9800;
    color: white;
}

.btn-lap:hover:not(:disabled) {
    background: #e68900;
}

/* ラップタイム */
.lap-times {
    margin-top: 30px;
}

.lap-times h3 {
    font-size: 18px;
    color: #333;
    margin-bottom: 15px;
    text-align: center;
}

#lap-list {
    list-style: none;
    max-height: 300px;
    overflow-y: auto;
}

#lap-list li {
    padding: 12px;
    margin-bottom: 8px;
    background: #f5f5f5;
    border-radius: 8px;
    font-size: 18px;
    font-variant-numeric: tabular-nums;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#lap-list li:first-child {
    background: #fff3cd;
    font-weight: bold;
}

/* タイマー終了時の視覚的通知 */
.timer-finished {
    animation: flash 0.5s infinite;
}

@keyframes flash {
    0%, 100% {
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    }
    50% {
        background: linear-gradient(135deg, #f44336 0%, #ff6b6b 100%);
    }
}

.timer-finished .container {
    animation: shake 0.5s infinite;
}

@keyframes shake {
    0%, 100% {
        transform: translateX(0);
    }
    25% {
        transform: translateX(-10px);
    }
    75% {
        transform: translateX(10px);
    }
}

.timer-finished .display {
    color: #f44336;
    animation: pulse 0.5s infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
}

/* レスポンシブ */
@media (max-width: 600px) {
    .container {
        padding: 20px;
    }

    h1 {
        font-size: 20px;
    }

    .display {
        font-size: 48px;
    }

    .timer-inputs {
        gap: 20px;
    }

    .input-group input {
        width: 70px;
        font-size: 20px;
    }

    .controls {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}

@media (max-width: 400px) {
    .display {
        font-size: 36px;
    }

    .input-group input {
        width: 60px;
        font-size: 18px;
    }
}